镉对花生品质影响及胁迫响应机制研究

近年来，我国花生重金属镉超标的现象屡见不鲜，致使花生在我国出口创汇的能力受到了严重影响。因此，本项研究选用北方两种花生－锦花5号和阜花13号为供试材料，采用室外盆栽方式，初步探讨了镉胁迫对花生品质的影响及花生对镉胁迫的响应机制，揭示了花生易富集镉和对镉高耐性的原因。 1．在外源高镉处理下，两品种花生的产量随镉处理浓度的增加而降低；籽实Cd含量均随土壤中Cd含量的增加而显著增加（p＜0.05），在土壤低Cd处理时，花生籽实更易富集Cd；花生受Cd胁迫后，籽实的亮氨酸含量受Cd的影响较为严重；氨基酸组成比例在较低镉处理剂量下未受到影响。 2．受Cd污染的花生籽实，种皮Cd含量较高；蛋白质是络合镉的主要营养部位，而脂肪中镉的含量甚微，研究处理范围内均低于食品中Cd的限量值0.2 mg•kg-1 ；因此供试花生籽实不能作为人体对植物蛋白的来源，但可以作为人体对食用油脂的来源。 3．花生籽实中存在植物螯合肽PC4，它在花生中镉的耐性方面发挥着重要的作用。尽管非蛋白巯基（NPT）、半胱氨酸（Cys）、PC4和脯氨酸（Pro）含量受作物品种和外源镉处理剂量的影响，但它们对籽实中重金属镉的络合发挥着作用。此外，脯氨酸（Pro）还可以作为花生受镉胁迫的生物指示物。

禄春安息香种子和攀援孔药花全草的化学成分研究

本文对禄春安息香（Styrax macranthus）种子和攀援孔药花（Porandra scandens）全草的化学成分进行了研究，共获得30个化合物，其中2个为新化合物。 从禄春安息香种子95%乙醇提取物中分离并鉴定了12个化合物，其中2个新化合物鉴定为3-[7-methoxy-2-(3,4-methylenedioxy phenyl) benzofuran-5-yl] propyl 3-[7-methoxy-2-(3,4-methylenedioxyphenyl)benzofuran-5-yl] propanoate (1) 和去甲氧基-egonol-龙胆双糖甙 (2)；已知化合物分别为2-(3,4-二氧亚甲基苯基)-5-甲酰基-7-甲氧基-苯并呋喃 (3)、egonol (4)、去甲氧基-egonol (5)、去甲基-egonol (6)、egonol-葡萄糖甙 (7)、egonol-龙胆双糖甙 (8)、egonol-龙胆三糖甙 (9)、豆甾醇 (10)、二十四烷酸 1-甘油酯 (11) 和胡萝卜甙 (12)。生物活性测试发现，化合物2具有促进雌激素E2合成的作用。 从攀援孔药花全草95%乙醇提取物中分离并鉴定了19个化合物：(2S,3S,4R)-2-[(2R)-2-羟基-二十一烷酰基氨基]-二十一烷-1,3,4-三醇 (13)、(2S,3S,4R)–2–二十四烷酰基氨基-十八烷-1,3,4-三醇 (14)、胡萝卜甙 (12)、β-谷甾醇 (15)、(20S,22E,24R)-5α,8α-表二氧-麦角甾-6,22-二烯-3β-醇 (16)、6β-羟基-豆甾-4-烯-3-酮 (17)、十六烷酸 1-甘油酯 (18)、桦木酸 (19)、大黄素 (20)、二十二烷酸 1-甘油酯 (21)、对羟基苯甲醛 (22)、十七烷酸 1-甘油酯 (23)、金色酰胺醇乙酸酯(24)、十九烷酸 1-甘油酯 (25)、棕榈酸 (26)、(E)-p-香豆酸 (27)、(22E,24S)-24-麦角甾醇-7,22-二烯-3β,5α,6β-三醇 (28)、2-去氧-β-蜕皮激素 (29)和auranamide (30)。 综述了近十年来发现的2－芳基苯并呋喃类新木脂素的结构特征、来源、生物活性和化学全合成。 Phytochemical investigation on the seeds of Styrax macranthus and the whole plants of Porandra scandens led to the isolation of thirty compounds, two of which were new ones. Two new 2-aryl benzofuran derivatives, 3-[7-methoxy-2-(3,4-methylenedioxy phenyl) benzofuran-5-yl]propyl 3-[7-methoxy-2-(3,4-methylenedioxyphenyl)benzo furan-5-yl]propanoate (1) and demethoxy egonol gentiobioside (2), were isolated from the 95% aqueous ethanolic extract of the seeds of Styrax macranthus, together with 7-methoxy-2-(3,4-methylenedioxyphenyl) benzofuran-5-carbaldehyde (3), egonol (4), demethoxy egonol (5), demethyl egonol (6), egonol glucoside (7), egonol gentiobioside (8), egonol gentiotrioside (9), stigmasterol (10), 2,3-dihydroxypropyl tetracosoate (11), and daucosterol (12). In vitro test, compound 2 promote the synthesis of estrogen E2. Nineteen compounds were isolated from the 95% aqueous ethanolic extract of the whole plant of Porandra scandens for the first time. Their structures were identified as (2S,3S,4R)-2-[(2R)-2-hydroxy-heneicosanoylamino]-1,3,4- heneicosanetriol (13), (2S,3S,4R)-2-tetracosanoylamino-1,3,4-octadecanetriol (14), daucosterol (15), β-sitosterol (12), (20S,22E,24R)-5α,8α-epidioxy-ergosta-6,22-diene- 3β-ol (16), 6β-hydroxylstigmast-4-en-3-one (17), 1-glycerol-1-hexadecoate (18), betulinic acid (19), emodin (20), 1-glycerol-1-docosoate (21), p-hydroxybenzaldehyde (22), 1-glycerol-1-heptadecoate (23), aurantiamide acetate (24), 1-glycerol-1- nonadecoate (25), palmatic acid (26), (E)-p-coumaric acid (27), (22E,24S)- 24-metbylcbolesta-7,22-diene-3β,5α,6β-triol (28), 2-deoxycrustecdysone (29), and auranamide (30). The characteristic, natural resource, bioactivity, and the total synthesis of 2-aryl benzofurans were reviewed.

瓦山安息香中苯并呋喃促雌激素合成的机理研究

雌激素是人体内重要的激素之一，具有广泛的生理功能。雌激素缺乏与许多疾病相关，如卵巢功能低下，更年期综合征以及骨质疏松等；雌激素过剩也将导致某些疾病，如乳腺癌、卵巢癌、子宫内膜癌等。目前，如何降低肿瘤组织中的雌激素水平而达到治疗肿瘤的目的，已经得到广泛的研究，但促雌激素生成或调节卵巢功能药物或其相关研究则很少。 本实验室前期的研究发现，瓦山安息香属植物果实中的乙醇提取物具有促雌激素生成作用，通过活性追踪和结构鉴定，确认促E2 生成的主要成分为苯并呋喃类化合物。苯并呋喃类化合物的作用与芳香酶有关，但其确切的作用机理有待证实和深入研究。 为了探讨安息香苯并呋喃类化合物的促雌激素合成的作用机理，拟采用如下的实验方案： 1、细胞学方面，对小鼠3T3-L1 前脂肪细胞、人乳腺癌细胞MCF-7、MDA-MB-231 以及人卵巢癌细胞OVCAR-3、OVCAR-4、OVCAR-5、OVCAR-8、IGROV1 等细胞株，采用RT-PCR 和ELISA 方法研究芳香酶Aro基因的表达和雌二醇E2 的生成，芳香酶抑制剂Formestane 作为阳性对照，研究时效曲线和量效曲线，确定安息香苯并呋喃类化合物SP25 的有效浓度和作用时间。 2、RNAi 方面，设计合成了针对人芳香酶Aro基因的3 对RNAi 序列，转染入细胞，芳香酶促进剂Forskolin 和地塞米松、芳香酶抑制剂Formestane 作为阳性对照，采用实时定量PCR 技术，研究RNA 干扰后，安息香苯并呋喃类化合物SP25 对人芳香酶Aro基因表达水平瓦山安息香苯并呋喃促雌激素合成的机理研究的影响。 3、雌激素受体方面，设计一段ERE 的雌激素调控元件，构建重组荧光素酶报告基因载体，瞬时转染人乳腺癌细胞株MDA-MB-231，建立针对雌激素受体的报告基因筛选模型，观察安息香苯并呋喃类化合物SP25 对雌激素受体的选择性和亲和力，从受体水平考察安息香苯并呋喃类化合物SP25 促进雌激素生成的药理学机理。 实验结果显示： 1、分化后的小鼠3T3-L1 前脂肪细胞、人乳腺癌细胞MCF-7 、MDA-MB-231 以及人卵巢癌细胞OVCAR-3、OVCAR-4、OVCAR-8 等细胞株具有芳香酶基因的表达。睾酮向雌二醇的转化能够被芳香酶抑制剂Formestane 所阻断，其中OVCAR-3 最适合进行下一步的RNAi研究。 2、RNAi 实验结果显示，设计的3 对RNAi 序列中R2 的干扰效果最强，相应的阴性对照C2 与R2 的表达量相差118 倍（24 小时）和19 倍（48 小时），显示R2/C2 这组序列可用于进一步的RNAi 试验。以R2 干扰OVCAR-3 细胞株，药物作用24、48 小时后，芳香酶抑制剂Formestane 与R2 相对表达量相比分别为0.83 倍和0.04 倍；芳香酶促进剂Forskolin 与R2 相对表达量相比分别为3.61 和1.84 倍；芳香酶促进剂地塞米松与R2 相对表达量相比分别为5.76 倍和3.49倍；苯并呋喃类化合物SP25 与R2 相对表达量相比分别为8.13 倍和4.59 倍。实验证实安息香苯并呋喃类化合物SP25 能够促进因RNAi 而发生基因沉默的人芳香酶Aro表达水平的上调。 3、雌激素受体实验结果显示，构建成功重组pERE-pGL3-promoter 荧光素酶报告基因载体和基于报告基因系统的雌激素受体激动剂或拮抗剂的细胞筛选模型。实验结果表明安息香苯并呋喃类化合物SP25 与雌激素受体ERα和ERβ亲和力选择性之比约为3：1 ，SP25通过与雌激素受体ERα结合作用其受体，刺激芳香酶的表达。 本课题通过RNA 干扰、ELISA、荧光实时定量PCR、报告基因筛选模型等技术手段，从细胞水平、蛋白酶水平和基因表达水平、雌激素受体水平等方面系统地研究了从瓦山安息香属植物果实中提取的苯并呋喃SP25 促进促雌激素生成的机理研究。试验结果显示苯并呋喃类化合物SP25 促雌激素生成的主要作用机制是直接促进芳香酶基因表达水平，以及与雌激素受体a 结合，刺激芳香酶活性。 Estrogen is an important hormone that has versatile physiologicalfunctions. Lack of estrogen will lead to many diseases such as lower ovarianfunction, climacteric syndrome and osteoporosis. Excessive estrogen alsoinduces breast carcinoma, oophoroma and endometrial carcinoma and otherdiseases. To depress the estrogen level in tumor tissue to cure carcinomawas widely studied, but there is only few studies reported on the induction ofestrogen and on the regulation of ovary function. We found that the extracts from seeds of Styrax perkinsiae couldpromote the synthesis of estrogen. The active compounds benzofurans wereidentified. Effect of benzofurans may be related to aromatase, but the mechanism was not clear. To reveal the mechanism of these benzofurans to promote estrogensynthesis, the following protocols were adopted: 1 Cytology: 3T3-L1 preadipocytes,human ovary carcinoma celllines OVCAR-3,OVCAR-4,OVCAR-5,OVCAR-8,IGROV1 andbreast carcinoma cell lines MCF-7 and MDA-MB-231 were usedto determine Aro gene expression and estrogen production withRT-PCR AND ELISA methods. Formestane, an aromataseinhibitor, was used as positive control. And dose-curve,time-curve and the effective concentration of SP25 were also studied. 2 Designed 3 pairs of RNAi for human aromatase gene, andtransfected into cell. Aromatase inducer Forskolin andDexamethasone, and aromatase inhibitor Formestane were usedas positive controls. We studied the change of Aro expressionlevel with SP25 by using real-time PCR after RNA interfering. 3 Estrogen Receptor: We constructed the recombined Luciferasereport vector and establish a screening system for estrogenagonist and antagon. With this system, we studied the affinity ofSP25 and estrogen receptor. Results: 1 Differentiated 3T3-L1 preadipocytes¡¢human ovary carcinomacell lines:OVCAR-3, OVCAR-4, OVCAR-8 and breast carcinomacell lines MCF-7, MDA-MB-231 had detected aromatase geneexpression.And OVCAR-3 is more suitable for further aromatasegene function research. 2 In RNAi assay, R2 has a strong interfering effcet in OVCAR-3 cellline, and ratio of C2 (the negative control) to R2 were 118 times(24 hours) and 19 times (48 hours). This means sucessful inRNA interfering. After R2 acted on OVCAR-3 cell line, the ratiosof formestane to R2 were 0.83 and 0.04 times, 5.76 and 3.49times (Dex), 3.61 and 1.84 times (forskolin) and 8.13 and 4.59times (sp25) after drug treated 24 or 48 hours respectively.These results indicated that SP25 can directly induce aromatasegene up-regulation. 3 We had constructed pERE-pGL3-promoter recombined vectorand the Luciferase report gene screening system. Luciferasereport gene assay showed that sp25 had a higher affinity with strogen receptor alpha than estrogen receptor beta, this indicated that SP25 can act on estrogen receptor and induce aromatase. Our results revealed that the mechanisms of benzofuran to promoteestrogen were the upregulation aromatase gene expression and promotion ofaromatase activity and have partially elective affinity with estrogen receptoralpha.

千金子和暖地大叶藓的化学成分研究

本论文由三部分共4 章组成。第一部分阐述了大戟科大戟属传统中药千金子（Euphorbia lathyris L.）化学成分、生物学活性以及千金子化学成分的HPLC、UPLC-MS、GC-MS 分析成果。第二部分介绍了民族药材暖地大叶藓（Rhodobryum giganteum (Schwaegr.) Par.）的化学成分研究和结构鉴定。第三部分概述了大戟属 植物中大环二萜酯的研究进展。 第一章包括1－3 节。在第1, 2 节中报道了千金子（Euphorbia lathyris L.）95% 乙醇提取物的化学成分分离鉴定。我们采用正、反相硅胶柱层析、重结晶等各种分离方法，凭借MS、IR、NMR、X-ray 等现代仪器手段,从中共分离鉴定22 个化合物。其中8 个是高活性化合物前体-续随子烷型大环二萜及3 个巨大戟烷型二萜，还有香豆素、生物碱、甾体等类型，其中完成对5 个大环二萜酯构型的确认，对2 个二萜酯构型进行了修正。第3 节中介绍对千金子化学成分的细胞毒性、α-葡萄糖苷酶抑制活性、P-gp 表达抑制活性的模型筛选结果。 第二章包括3 节，第1 节报道不同产地千金子高效液相色谱定量分析结果。第2 节介绍了各大环二萜酯的HPLC-MS/MS 的分析结果，并且对其质谱裂解规律、UPLC-MS 快速鉴定方法做了进一步讨论。第3 节介绍了千金子挥发油成分分析。采用传统水蒸气蒸馏方法提取千金子中的挥发油，并经气相色谱－质谱联用（GC-MS）技术共分离鉴定出 49 个化合物，占挥发油总量的90.48％。 第三章包括1, 2 两节，第1 节报道了暖地大叶藓化学成分。采用正、反相硅胶，凝胶柱层析等各种分离方法和MS、IR、NMR 等解析手段，共分离鉴定10个化合物，其中一个环肽化合物为新化合物。第2 节介绍了暖地大叶藓挥发油成分分析，共分离鉴定出 52 个化合物，占其挥发油总量的85.67％。 第四章概述了大戟科大戟属植物中大环二萜酯的研究进展。 This dissertation consists of three parts. In the first part, it is elaborated that the phytochemical investigation from the traditional Chinese medicine: seeds of Euphorbia lathyris L.. Biological activity and constituents analysis by HPLC、UPLC-MS、GC-MS were reported. In the second part, it is discussed that the chemical constituents were isolated and identificated from minority nationalitical herb－Rhodobryum giganteum (Schwaegr.) Par.. The third part is a review about the progress of studies on macrocyclic diterpenes from Euphorbia. The first part is composed of 1－3 sections. The section 1and 2 is focused on the isolation and identification of chemical constituents from seeds of E. lathyris. 22 compounds were isolated from the seeds of E. lathyris. by isolation methods of column chromatography (silica gel, including reversed phase) and recrystallisation on the basis of spectroscopic methods including IR, MS, NMR and X-ray. In 8 macrocyclic and 3 ingenane diterpenes, the relative configuration of 5 macrocyclic diterpenes were confirmed, in which 2 were amended. In the third section, cell cytotoxic activity, restraining activity of α-Glucosidase and multidrug resistance (MDR) reversing activity about P-gp were tested. 5 potential revsering reagents were found. The second part is composed of 1－3 sections. In first section it is described that the quality of the chemical constituents of E. lathyris from 5 sources , which were analyzed by high-performance liquid chromatography. In addition, the fractionation rules of some macrocyclic diterpenes were discussed and Ultra Performance Liquid Chromatography/ electrospray ionization mass spectrometry (UPLC-MS) was applied for quick determination of compounds in the second section. In the third section, chemical analysis of the essential oil from seeds of E. lathyris by GC-MS were reported. The essential oil from the seeds of E. lathyris L. in Sichuan was extracted by steam distillation and 49 compounds were isolated and identified from the essential oil by gas chromatography-mass spectrometer (GC-MS). These compounds are accounted for 90.46% of the total essential oil. The second part, including section 4 and 5, is about the phytochemical investigation of R. giganteum. In the former section, ten compounds were isolated and identified. Among them, a new peptide was characterized by spectroscopic analysis including IR, MS and NMR. In the other section, 52 compounds were isolated and identified from the essential oil by gas chromatography-mass spectrometer (GC-MS). These compounds are accounted for 85.67% of the total essential oil. The third part is a review about the progress of studies on macrocyclic diterpenes from Euphorbia.

川西亚高山云杉人工林天然更新与生境异质性研究

川西亚高山针叶林是四川森林的主体，是长江上游重要的生态屏障。云杉作为亚高山针叶林人工更新的主要树种，已经在该地区形成了大面积的人工纯林。目前，许多云杉人工林分已经进入更新成熟龄，而这些人工林的持续更新却成为日益凸现的问题。探讨这些云杉人工林的自我更新潜力及云杉种子种群更新特点，可为培育后续森林资源提供科学依据。 本文以川西米亚罗亚高山60a云杉人工林为研究对象，并以该区域内相对稳定的植被群落——天然林为对照，采用种子收集器、土壤种子库筛选、室内外种子萌发实验及野外幼苗调查等方法，从异质性微生境的角度研究了种子雨下落之后，不同微生境对种子库、种子萌发、幼苗建立及分布这一前期更新过程的影响，得出如下结果： 1、通过对川西亚高山60a云杉人工林和天然林6年内种子雨雨量、形态特征、散步动态等的持续观测和综合比较可以发现，云杉林结实特点由于林木自身的特征存在着巨大的变动，2002年和2006年两个种子结实大年内，60a人工林种子雨强度分别达到1088.2 ± 52.3粒/m2和704.3 ± 48.9粒/m2，远大于天然林579.9 ± 28.9粒/m2 和507.5± 30.7粒/m2；且云杉林结实质量优于天然林。60a人工林结实量大，种子质量也最好，相对天然林来说对种群的天然更新以及群落的演替都有最大的贡献潜力。应该说，在川西亚高山云杉人工林的天然更新过程中，种源不是影响天然更新的因素。在种子结实大年里，达到更新成熟的云杉人工林有着优于该地区相对稳定植被群落——天然林的种源优势。至少在种子结实大年，种子供应不是该区域人工林天然更新的限制因子。 2、相对于天然林种子库，人工林种子库在种子萌发前能够有较多的有活力种子。虽然这其中有种子雨输入量有差别的因素存在，但两种林分种子库对种子的保存率的不同才是造成这种差异的主要因素。在人工林中，不同地被类型形成的微生境显著地影响了种子库中种子的密度、垂直分布。有地被物存在的微生境能够将种子雨的大部分截留在地被层中，成为幼苗出现的主要场所；同时不同的地被物对种子的保存情况存在显著的差异，苔藓和凋落物层能都较好地保持其中的种子，到种子萌发前，这两种种子库类型能分别为天然更新提供366.1粒/m2和302粒/m2的有效种子。从这点来看，林下地被物上的种子库能够为天然更新萌发阶段提供数量可观的物质基础。 3、种子的萌发和幼苗的定居是天然更新过程中种子库向幼苗库转化的关键环节。总的说来，米亚罗人工林区60a云杉人工林种子向幼苗的转化率十分低下，凋落物、苔藓、草本、裸地四种主要地被物以及天然林内种子/幼苗的转化率分别仅为2.22%、2.14%、0.57%、0.67%、1.05%。这种低的转化率成为云杉林天然更新的限制性因子。但在现有更新条件下，微生境对这一环节仍然显示出十分显著的影响，表现为凋落物和苔藓对现有更新的新幼苗的保存率高于其它类型及天然林。苔藓和凋落物在种子萌发，幼苗保存，以及幼苗分布上都要优于其它地被物类型；另外，微地形对天然更新过程的影响也很显著，凹立地上更适宜于种子的汇集、萌发和定居。 Subalpine coniferous forests dominate most parts of the forested areas in western Sichuan, and they are important ecological barriers in the upper reaches of the Yangtze River. Picea asperata is one of the keystone spruce species for re-afforestation after felling of the natural forests and there have been a total of ca. 13 000 ha of plantations dominate by this species established. Nowadays, many P. asperata plantations have reached reproductive maturity. However, continued regeneration becomes to an important problem in these plantations. Understanding their self-regeneration potential and the regeneration characteristics of seed populations in spruce plantations of these plantations can have some insights on the management of these plantations and the establishment of following forest resources. A subalpine 60a P. asperata plantation distributed in Miyaluo artificial forest area was studied in this paper, at the same time. Synchronously, a 150a natural spruce forest was studied as comparison. Using seed collecting traps, sieving method for soil seed bank, seed germination experiments and seedling investigations in the field, the effects of heterogeneous microsites on early natural regeneration processes after seed rain were studied, which included seed banks, seed germination, seedling establishment and distribution. The main results are as follows. 1. Through a 6-year long term investigation of seed rain intensities, characteristic, dispersal dynamics of 60a P. asperata plantation, we could concluded that the seed setting properties of 60a P. asperata plantation have a great variation for the characteristics trees. In the mast seed year of 2002 and 2006, the seed rain intensities of plantation was 1088.2 ± 52.3 seeds/m2 and 704.3 ± 48.9 seeds/m2 respectively, which were much greater than that of natural spruce forest (579.9 ± 28.9 seeds/m2 in 2002, and 507.5± 30.7 seeds/m2 in 2006). Furthermore, the quality of seed rain in P. asperata plantation was better than that of natural spruce forest. Contrasting with natural spruce forest, 60a P. asperata plantation has a greater potential on natural regeneration of P. asperata population and succession of community for the reason of greater seed rain intensities and better seed quality. We can confirm that seed source was not a limiting factor which influences the natural regeneration progress of P. asperata population distributed in subalpine mountain zone, at least in the mast seed year. 2. Contrasting with natural spruce forest, P. asperata population had more viable seeds in seed bank before the germination. Although the difference of seed rain intensities of two forests has effect on this phenomenon, the difference of seed conservation ability in two forests was the main factor. In the P. asperata plantation, the seed densities and seed vertical distribution pattern were significant effected by the microsites, which posed by different ground cover types. In other word, Microsite with ground covers can obstruct most seeds and keep them in ground cover layer from seed rain, and these ground covers would be the main site for seed occurrence. There was a significant difference about seeds conservation ability among these ground covers. Litter and moss could better conserve P. asperata seeds which distributed in this two covers. Seed banks exist in litter and moss ground cover types could respectively provide 302seed/m2 and 366.1seed/m2 for natural regeneration before the seed germination. From this point of view, we could conclude that ground covers can ensure considerable numbers of seeds for the germination process. 3. Seed germination and seed establishment are key steps that the seeds invert to seedlings in natural generation process. In sum, the seed/seeding transform rate in 60a P. asperata plantation distributed in Miyaluo artificial forest area is very low. the seed/seeding transform rates in litter, moss, herb, soil surface and natural spruce forest were 2.22%、2.14%、0.57%、0.67%、1.05%, respectively. The low transform rate become to a limiting factor of P. asperata natural regeneration process. However, under the existing conditions of natural regeneration, microsit still had significant effect on this transform. The states of Seed germination, new seedling conservation, and older seedling distribution in litter and moss were better than in any other ground cover type or natural spruce forest. In addition, the micro-relief has significant effect on natural regeneration process. Concave site was more suitable for seed collection, seed germination and seedling distribution.

岷江上游高山林线附近优势树种土壤种子库和幼苗更新特征的研究

岷江上游地区高山/亚高山植被分布的坡向性分异显著，阴阳坡高山林线不仅物种组成差异明显，并且分布海拔呈现出阴坡高阳坡低的格局．阳坡林线树种主要是圆柏属乔木，林线类型多为渐变型，海拔高度大约在3 400m~3 800m；阴坡林线树种主要是冷杉，林线类型多为骤变型，海拔高度约在3 800m~4 400m．本研究采用土壤种子库物理筛选、室内萌发实验及野外群落调查等方法，对岷江上游地区阴坡岷江冷杉和阳坡祁连圆柏两类林线树种不同海拔梯度上土壤种子库以及幼苗库特征进行了调查，从土壤种子库和幼苗更新特征的角度对林线乔木树种种群更新特征进行了分析，进而对该地区高山林线在阴阳坡分布差异的原因进行了探讨，结果显示： 1．土壤种子库 阴坡：阴坡高山林线附近岷江冷杉土壤种子的平均密度大约为50.96粒/m2，其中树线以上10m处土壤种子密度为1.00粒/m2，树线处大约19.33粒/m2，林线交错带内土壤种子密度最高为136.83粒/m2，郁闭林内种子密度小于林线交错带，只有30.50粒/m2，种子平均空壳率为52％，霉变率达34%，完好种子只有6%．土壤种子库垂直分布特征为地被物层含种子比重最大，大约在67.50%左右；其次为0~2cm层，约18.84%左右；2~5cm层所占种子比例最小，约13.66%左右．霉变种子数量与土壤深度呈负相关． 阳坡：阳坡祁连圆柏土壤种子的平均密度为60.16粒/m2．树线以上10m处密度为1.92粒/m2，树线位置大约108.16粒/m2，林线交错带内平均为75.80粒/m2，郁闭林内种子密度小于林线交错带，只有20.00粒/m2．种子平均空壳率为36％，完好种子占49%，霉变率较低，大约为10%．阴阳坡林线树种土壤种子库垂直分布特征为：地被物层含种子最多，其次为0~4cm层，4~10cm层所占种子比例最小，霉变种子数量与土壤深度也呈负相关． 2． 幼苗库调查 阳坡：在树线以上区域没有发现幼苗，林线交错带内幼苗密度平均达3 250株/hm2，郁闭林内仅2 750株/ hm2．整个样地内1～2a幼苗很少甚至没有出现，3～10a的幼苗相对较多．空间分布上，祁连圆柏幼苗在林线交错带内接近随机分布，郁闭林内则介于随机分布和均匀分布之间． 阴坡：在树线以上幼苗密度为1 250株/ hm2，全部为1~2a幼苗，林线交错带内幼苗密度平均达7 000株/ hm2，郁闭林内达6 250株/ hm2．林线附近岷江冷杉幼苗丰富度以及幼苗的出现频率明显高于祁连圆柏，年龄结构也较祁连圆柏完整．岷江冷杉幼苗空间分布除了树线处幼苗的分布为随机分布，其他海拔则为集群分布． 3．从不同土壤深度的种子总量和幼苗数量的相关性检验发现，当年生幼苗数量跟表层种子总量相关性极显著, 但是两年生幼苗的数量与底层种子数量相关性显著．土壤种子在土壤中的垂直分布格局从一定程度上可以反映种子库的年际特征．岷江冷杉土壤种子库较丰富，种子散布后的存活力随着时间的变化逐渐下降，属于季节性瞬时种子库；祁连圆柏土壤种子散布格局为集群型分布，成熟种子大部分散布在母株冠幅内，属于永久性土壤种子库． 4．在阴坡林线交错带及以上区域还存在较为丰富的乔木土壤种子，并且在树线以上区域还发现了少量的岷江冷杉幼苗．从样地乔木的年龄结构发现，在林线交错带内上部到树线位置主要以幼龄林为主，且年龄结构完整，基本符合入侵性林线特征；阳坡林线交错带内幼苗出现频率很低，树线以上区域虽然存在种子库，但是没有幼苗出现，在林线交错带内乔木径级差距很大，年龄结构异常不完整，这种特征的林线将会面临两个可能结果：一种是维持现有状态，保持平衡；另外一种就是退化，但阳坡林线的实际动态趋势还有待长期定点研究． Treelines on the upper region of Minjiang River differ between the north aspect and the south aspect in their appearances, altitudes and tree species. On the north aspect, trees of Abies form a sharp and abrupt treeline ranging from 3800m to 4400m, while on the south the treeline is generally lower(3 400~3 800m), more open and gradual and mostly composed of Sabina. In this study, we examined the altitudinal gradients of soil seed banks and seedling recruitments at the treeline ecotones of a N-aspect and a S-aspect by using soil sieving, germination experiment and field investigations, analyzed the characteristics of population regeneration of tree species at the transitional zone and presented a analysis of the causes to the aspect-related difference in treeline patterns in the study area. Major results of our study include: 1． Soil seed bank N-aspect: Of the 50 plots investigated, the average density of soil seeds is 50.96/m2, in which well-formed seeds account for 6%, empty seeds 52%, parasitized seeds34%, and seeds damaged by animals 8%. The size of soil seed bank varies along altitude, being 1.00 seeds /m2 at the 10m above the treeline and ca.19.33 seeds/m2 at the upper limit of treeline. The highest density (136.83 seeds/m2) occurs at the treeline ecotone. By contrast, the density of soil seed for the closed forest is only 30.50 seeds/m2. In terms of vertical strata, 67.50% of the total seeds are at the surface layer, 18.84% at the middle layer (0~2cm) and 13.66% at deeper layer (2~5cm). The number of parasitized seeds is negatively correlated to soil depth. S-aspect: Of the 50 plots investigated, the average density of soil seeds is 60.16 seeds/m2, and the well-formed seeds account for 49%, empty seeds 36%, parasitized seeds10%, and seeds damaged by animals 1%. The size of soil seed bank varies along altitude, with 1.92 seeds/m2 recorded at the10m above the treeline，108.16 seeds/m2 at the upper limit of treeline, and 75.80 seeds/m2 at the treeline ecotone, while that for the closed forest is 20.00 seeds/m2. The number of seeds decreases with the depth of soil. As is on the N-aspect, the size of soil bank, from large to small, follows the order of the surface layer, the middle layer (0~4cm) and the bottom layer (4~10cm). The number of parasitized seeds is also negatively correlated to the depth of the soil. 2． Seedling bank N-aspect: A mean maximum seedling abundance of 31 000 seedlings/hm2 was recorded near alpine treeline at growing season. The density of seedlings is 1 250 seedlings/ha (all being 1 or 2 years old) at the alpine meadow 10m away above treeline, 7 000 seedlings/ha at treeline ecotone and 6 250 seedlings/ha for closed forest．The spatial distribution of Abies faxoniana seedlings is random at the upper limit of the treeline but clumped at other altitudes． S-aspect: No seedlings were found at the alpine meadow 10m away from the treeline. The density of seedlings was 3 250 seedlings/ha at treeline ecotone and 2 750 seedlings/ha for the closed forest．Hardly any 1 year current and 2 year-old seedlings appeared at the plots. The spatial distribution of Sabina przewalskii seedlings is random at treeline ecotone and between “random” and “even” forest closed forest． 3．Correlation tests of seedling population and seed bank at different soil layers indicated that the emergents were strongly correlated to seed bank at surface layer while the number of two-year seedlings was significantly correlated to the seed bank at the bottom of soil layer, indicating that germination mainly occurs at the soil surface while the middle or bottom layer was the reserve for non-germination or dead seeds. It can thus be postulated that Abies faxoniana soil seed bank is of seasonal transient type. By contrast, the soil seed bank of Sabina przewalskii is of persistent type and the soil seeds and seedlings of this species occurred more frequently near the islands of adult trees. 4．A good many soil seeds of both tree species were found near the treeline ecotone and above at N- and S-aspects. A few young seedlings were found above the Abies treeline. Investigation of five altitudinal transects respectively on N- and S-aspects indicated that Abies faxoniana has a more complete age structure than the stands of Sabina przewalskii. The age of firs decreased from closed forest to the upper limit of treeline, which suggests that the Abies treeline is advancing to higher altitude. While on the south aspect, only few Sabina przewalskii soil seeds and nearly no seedlings were found above the treeline ecotone. The stands exhibit extremely great difference in diameter classes with significantly incomplete age structure. This would lead to two possible results for the treelines: maintaining an equilibrium state at the current position or degenerating. But more studies should be carried out at longer time scales or larger spatial scales to understand whether the Sabina treeline is degenerating.

三种豆科灌木对干旱胁迫的响应与适应

干旱胁迫是全球范围内影响植物生存、生长和分布的重要环境因子。岷江上游干旱河谷区，由于生态环境的脆弱性和长期人类活动的干扰和过度利用，导致植被严重退化，水土流失加剧，山地灾害频繁，干旱化和荒漠化趋势明显。这种趋势若不能遏制，将严重阻碍区域社会经济的快速协调发展，并且威胁成都平原地区的发展和长江中下游地区的生态安全。因而开展干旱河谷生态恢复研究成为解决这些问题的关键。水分匮乏是限制干旱河谷生态恢复的关键因子，在全球气候变化的背景下，干旱胁迫在区域尺度上可能会更加严重，并使干旱河谷的生态环境更加恶化。因此，深入研究干旱河谷乡土植物对干旱胁迫的响应和适应机理，具有非常重要的理论和实践意义。 本论文以岷江上游干旱河谷的三种乡土豆科灌木，白刺花（Sophora davidii）、小马鞍羊蹄甲（Bauhinia faberi var. microphylla）和小雀花（Campylotropics polyantha）理论和实践意义。为研究对象，在人工控制条件下设计了4-5个连续性干旱胁迫处理，系统地研究了灌木幼苗的生长、生物量积累和水分利用效率（WUE）、形态结构和生理过程等对干旱胁迫的反应，揭示了幼苗的干旱适应能力及种间差异。主要研究结论如下： 1) 灌木生长和繁殖对干旱胁迫的反应 在干旱胁迫下，幼苗生长速率显著减小，叶片衰老和脱落比率增大，这些变化随着胁迫强度的增加具有累积效应。叶片比茎对干旱胁迫的反应更敏感。在严重干旱胁迫下，幼苗的有性繁殖被限制，但在中等程度干旱胁迫下，幼苗的有性繁殖能力被提高。 2) 灌木生物量积累及其分配和WUE对干旱胁迫的反应 在干旱胁迫下，灌木各器官的生物量都显著减小，但是生物量的分配侧重于地下部分，使得根茎比在干旱条件下增大。幼苗的耗水量（WU）随着干旱胁迫的增加而显著减少。白刺花和小马鞍羊蹄甲WUE在干旱胁迫下降低；小雀花的WUE在中等干旱胁迫下升高。 3) 灌木叶片结构特征对干旱胁迫反应 白刺花叶片具有较为典型的旱生型结构，而小马鞍羊蹄甲和小雀花则为中生型结构。在1至2年的干旱胁迫下，灌木叶片结构组成未发生本质性的改变，主要是细胞大小的变化。在中等和严重干旱胁迫下，叶肉组织厚度明显减小；并且气孔和表皮细胞面积也显著减小，气孔和表皮细胞密度显著增大；叶肉细胞层数、P/S值、表皮厚度等无显著变化。 4) 灌木对干旱胁迫的生理响应 气体交换参数和叶片相对含水量（RWC）在中等干旱胁迫下发生了明显的改变，而叶绿素荧光参数和光合色素含量在严重干旱胁迫下才发生显著变化。在干旱胁迫下，净光合作用速率（Pn）、气孔导度（gs）和RWC呈下降趋势，而叶片温度（Tl）呈增加趋势，蒸腾速率（Tr）的变化不明显。除了日最大Pn减小以外，干旱胁迫对气体交换参数的日变化无显著影响，但是对光合-光响应曲线有显著的影响，使有效光合时间缩短。在严重干旱胁迫下光系统受到损害而代谢减弱，PSⅡ中心的内禀光能转换效率（Fv/Fm）、量子产量（Yield）、光化学淬灭参数（qP）显著降低，而非光化学淬灭参数（NPQ）明显增加。气孔限制和非气孔限制对Pn的影响与干旱胁迫强度有关。在中度胁迫下，气孔限制起主导作用，在严重胁迫下非气孔限制起主导作用，40% FC水分条件可能是灌木由气孔限制向非气孔限制的转折点。 5) 灌木对干旱胁迫的适应能力及其种间差异 三种灌木对干旱胁迫具有较好的适应能力，即使在20% FC，幼苗未因干旱胁迫III而死亡；80% FC适宜于幼苗生长。白刺花生长速率慢，耗水量较少，具有较强的耐旱和耐贫瘠能力，并具有干旱忍受机制，能够在较干旱的环境中定居和生长。小马鞍羊蹄甲和小雀花，生长快，水分消耗量较大，尤其是小雀花，对干旱胁迫的忍受能力较弱，具有干旱回避机制，因而适宜于在较为湿润的生境中生长。综合分析表明，生长速率较慢的物种抗旱能力较强，其更适宜于作为干旱地区植被恢复物种。 Drought is often a key factor limiting plant establishment, growth and distribution inmany regions of the world. The harsh environmental conditions and long-termanthropogenic disturbance had resulted in habitat destruction in the dry valley ofMinjiang river, southwest China. Recently, it tended to be more severe on the vegetationdegradation, soil erosion and water loss, natural disaster, as well as desertification, whichimpact on regional booming economy and harmonious development, and would be verydangerous to the environmental security in the middle and lower reaches of Yangzi River.Therefore, ecological restoration in the dry valley is one of the vital tasks in China. Waterdeficit is known to affect adversely vegetation restoration in this place. Moreover, in thecontext of climate change, an increased frequency of drought stress might occur at aregional scale in the dry valleys of Minjiang River. The selection of appropriate plantingspecies for vegetation restoration in regard to regional conditions is an important issue atpresent and in further. The research on responses of indigenous species to drought stresscould provide insights into the improvement of the vegetation restoration in the dry valleys of Minjiang River. In this paper, the responses of three indigenous leguminous shrubs, Sophora davidii,Bauhinia faberi var. microphylla and Campylotropics polyantha, to various soil watersupplies were studied in order to assess drought tolerance of seedlings, and to compare interspecific differences in seedlings’ responses to drought stress. The results were as follows: 1 Growth and reproduction of shrubs in response to drought stress Seedling growth reduced significantly while leaf senescence accelerated underdrought stress, the cumulative responses to prolonged drought were found. The capacityfor reproduction was limited by severe drought stress, and improved by moderate droughtstress. Leaf responses were more sensitive than shoot to various water supplies. 2 WUE, biomass production and its partitioning of shrubs in response to drought stress Drought stress reduced significantly the total dry mass and their components ofseedlings, and altered more biomass allocation to root system, showing higher R/S ratiounder drought. Water use (WU) and water-use efficiency (WUE) of both S. davidii and B.faberi var. microphylla declined strongly with drought stress. The WU C. polyantha ofalso declined with drought stress, but WUE improved under moderate drought stress. 3 Anatomical characteristics and ultrastructures of leaves in response to drought stress There were xeromorphic for S. davidii leaves and mesomorphic for B. faberi var.microphylla and C. polyantha at the all water supplies. The foundational changes in leafstructures were not found with drought stress. However, mesophyll thickness, the areas ofstomatal and epidermis reduced slightly while the densities of stomatal and epidermisincreased under severe drought stress. Variations in these parameters could mainly be duoto cell size. Other structures did not displayed significant changes with drought stress. 4 Physiological responses of shrubs to drought stress The gas exchange parameters and leaf relative water content (RWC) were affectedby moderate stress, while chlorophyll fluorescence and chlorophyll content were onlyaffected by severe stress. Drought stress decreased net photosynthesis rate (Pn), stomatalconductance, light-use efficiency and RWC, and increased leaf temperature. Therespiration rates (Tr) were kept within a narrower range than Pn, resulting in aprogressively increased instantaneous water use effiecency (WUEi) under drought stress.Moreover, drought stress also affected the response curve of Pn to RAR, there was adepression light saturation point (Lsat) and maximum Pn (Pnmax) for moderate andsevere stressed seedling. However, diurnal changes of gas exchange parameters did notdiffer among water supplies although maximum daily Pn declined under severe stress.VISevere stress reduced Fv/Fm, Yield and qP while increased NPQ and chlorophyll content.Photosynthetic activity decreased during drought stress period due to stomatal andnon-stomatal limitations. The relative contribution of these limitations was associatedwith the severity of stress. The limitation to Pn was caused mainly by stomatal limitationunder moderate drought stress, and by the predominance of non-stomatal limitation undersevere stress. In this case, 40% FC water supply may be a non-stomatal limitation 5 Interspecific differences in drought tolerance of shrubs Three shrubs exhibited good performance throughout the experiment process, evenif at 20% FC treatment there were no any seedlings died, 80% FC water supply wassuitable for their establishment and growth. S. davidii minimized their water loss byreducing total leaf area and growth rate, as well as maintained higher RWC and Pncompared to the other two species under drought stress, thus they might be more tolerantto the drought stress than the other two species. On the contrary, it was found that C.polyantha and B. faberi var. microphylla had higher water loss because of their stomatalconductance and higher leaf area ratios. They reduced water loss with shedding theirleaves and changing leaf orientation under drought stress. Based on their responses, thestudied species could be categorized into two: (1) S. davidii with a tolerance mechanismin response to drought stress; (2) C. polyantha and B. faberi var. microphylla withdrought avoidance mechanism. These results indicated that slow-growing shrub speciesare better adapted to drought stress than intermediate or fast-growing species in present orpredicted drought conditions. Therefore, selecting rapid-growing species might leavethese seedlings relatively at a risk of extreme drought.

中国沙棘(Hippophae rhamnoides subsp. sinensis)天然群体的遗传变异分析

近十年，植物群体遗传学的研究飞速发展，然而与海拔相关的植物群体遗传结构和遗传变异研究却相对较少。到目前为止，还不清楚遗传变异与海拔之间是否有一个通用的格局。在山区，各种生态因子，如温度、降水、降雪、紫外线辐射强度以及土壤成分都随海拔梯度急剧变化，造成了即使在一个小的空间区域，植被类型变化显著，这种高山环境的异质性和复杂性为我们研究植物群体遗传结构和分化提供了方便。沙棘(Hippophea)属于胡颓子科(Elaeagnaceae)为多年生落叶灌木或乔木，雌雄异株，天然种群分布极为广泛。中国沙棘(H. rhamnoides subsp. sinensis)是沙棘属植物中分布较广的一个亚种，种内形态变异非常丰富，加之其具有独特的繁育系统和广泛的生态地理分布，是研究沙棘属植物遗传变异和系统分化的理想材料。本文从1,800 m 到3,400 m 分5 个海拔梯度进行取样，用RAPD 和cpSSR 分子标记研究了卧龙自然保护区中国沙棘天然群体的遗传结构和遗传变异。5 个取样群体依次标记为A、B、C、D 和E，它们分别代表分布在海拔1,800，2,200，2,600，3,000 和3,400 m 的5 个天然群体。RAPD实验用11 条寡核苷酸引物，扩增得到151 个重复性好的位点，其中143 个多态位点，多态率达94.7%。在5 个沙棘群体中，总遗传多样性值(HT)为0.289，B群体内的遗传多样性值为0.315，这完全符合沙棘这种多年生、远交的木本植物具有高遗传变异的特性。5 个群体内遗传多样性随海拔升高呈低－高－低变异趋势，在2,200 m海拔处的B群体遗传多样性达最大值0.315，3,400 m海拔处的E群体则表现最小仅0.098。5 个群体间的遗传分化值GST＝0.406，也即是说有40.6%的遗传变异存在于群体间，1,800 m海拔处的A群体与其它群体的明显分离是造成群体间遗传分化大的原因。UPGMA聚类图和PCoA散点图进一步确证了5 个群体间的关系和所有个体间的关系。最后，经过Mantel检测，遗传距离与海拔表现了明显的相关性(r = 0.646, P = 0.011)。cpSSR 实验中，经过对24 对cpSSR 通用引物筛选，11 对引物能扩增出特异性条带，只有2 对引物(ccmp2 和ARCP4)呈现多态性。4 个等位基因共组合出4 种单倍型，单倍型Ⅰ出现在A 群体的所有个体和B 群体的8 个个体中，C、D、E 三个群体均不含有，而单倍型Ⅱ出现在C、D、E 三个群体的所有个体及B 群体的18 个个体中，A 群体不含有。另外两种单倍型Ⅲ和Ⅳ为稀有类型，仅B 群体中的4 个个体拥有。这种单倍型分布模式和TFPGA 群体聚类图揭示了，C、D、E 群体可能来源于同一祖先种，而A 群体却是由另一祖先种发展起来的，B 群体则兼具了这两种起源种的信息，这可能是因为在历史上的某一时期，在中国沙棘群体高山分化的过程中，B 群体处某个或者某些个体发生了基因突变，具备了适应高海拔环境的能力，产生了高海拔沙棘群体的祖先种。 In recent ten years, studies about population genetics of plants developed rapidly,whereas their genetic structure and genetic variation along altitudinal gradients have beenstudied relatively little. So far, it is uncleared whether there is a common pattern betweengenetic variation and altitudinal gradients. In the mountain environments, importantecological factors, e.g., temperature, rainfall, snowfall, ultraviolet radiation and soil substratesetc., change rapidly with altitudes, which cause the vegetation distribution varying typically,even on a small spatial scale. The mountain environments, which are heterogeneous andcomplex, facilitate and offer a good opportunity to characterize population genetic structureand population differentiation.The species of the genus Hippophae L. (Elaeagnaceae) are perennial deciduous shrubs ortrees, which are dioecious, wind-pollinated pioneer plants. The natural genus has a widedistribution extending from Northern Europe through Central Europe and Central Asia toChina. According to the latest taxonomy, the genus Hippophae is divided into six species and12 subspecies. The subspecies H. rhamnoides ssp. sinensis shows significant morphologicalvariations, large geographic range and dominantly outcrossing mating system. Thesecharacteristics of the subspecies are favourable to elucidate genetic variation and systemevolution. To estimate genetic variation and genetic structure of H. rhamnoides ssp. sinensisat different altitudes, we surveyed five natural populations in the Wolong Natural Reserve at altitudes ranging from 1,800 to 3,400 m above sea level (a.s.l.) using random amplifiedpolymorphic DNA markers (RAPDs) and cpSSR molecular methods. The five populations A,B, C, D, and E correspond to the altitudes 1,800, 2,200, 2,600, 3,000 and 3,400 m,respectively.Based on 11 decamer primers, a total of 151 reproducible DNA loci were yielded, ofwhich 143 were polymorphic and the percentage of polymorphic loci equaled 94.7%. Amongthe five populations investigated, the total gene diversity (HT) and gene diversity within population B equaled 0.289 and 0.315, respectively, which are modest for a subspecies of H.rhamnoides, which is an outcrossing, long-lived, woody plant. The amount of geneticvariation within populations varied from 0.098 within population E (3,400 m a.s.l.) to 0.315within population B (2,200 m a.s.l.). The coefficient of gene differentiation (GST) amongpopulations equaled 0.406 and revealed that 40.6% of the genetic variance existed amongpopulations and 59.4% within populations. The population A (1,800 m a.s.l.) differed greatlyfrom the other four populations, which contributes to high genetic differentiation. A UPGMAcluster analysis and principal coordinate analyses based on Nei's genetic distances furthercorroborated the relationships among the five populations and all the sampling individuals,respectively. Mantel tests detected a significant correlation between genetic distances andaltitudinal gradients (r = 0.646, P = 0.011).Eleven of the original 24 cpSSR primer pairs tested produced good PCR products, onlytwo (ccmp2 and ARCP4) of which were polymorphic. Four total length variants (alleles) werecombined resulting in 4 haplotypes. The haplotype was present in all individuals of Ⅰpopulation A and 8 individuals of populations B, the other three populations (C, D and Epopulations) did not share. The haplotype was present in all individuals of populations C, D Ⅱand E and 18 individuals of populations B, population A did not share. The other twohaplotypes and were rare haplotypes, which were only shared in 4 individuals of Ⅲ Ⅳpopulation B. The distribution of haplotypes and TFPGA population clustering map showedthat the populations C, D and E might be origined from one ancestor seed and population Amight be from another, whereas population B owned information of the two ancestor seeds. Itwas because that gene mutation within some individual or seed in the location of population Bwas likely to happen in the history of H. rhamnoides, which was the original ancestor of thehigh-altitude populations.

化感物质香豆素对苜蓿种子萌发及幼苗初级氮同化的影响

香豆素类物质是苯丙酸内酯（环酯）类化合物，绝大部分高等植物通过次生代谢途径都能合成。研究表明，香豆素类物质是花椒体内最重要的化感物质，系统研究香豆素类物质的作用机理有助于理解和最终解决花椒连作障碍。本文通过研究香豆素对几种植物种子特别是苜蓿种子萌发、苜蓿幼苗初级氮同化的影响，从生理生化角度揭示香豆素的作用方式，为花椒连作障碍的解决和化感作用机制的深入理解提供依据。主要研究结果如下：1. 研究了香豆素对6 种常见作物种子萌发的影响，并对一组数据采用4个不同的指标进行评价，对生物测定化感作用中存在的问题进行了讨论。结果发现1.0mM的香豆素对采用的6 种作物的种子萌发均表现出一定的化感作用，4 个指标的敏感程度依次为S (发芽速度)＞AS(累积发芽速度)＞CRG(发芽指数)＞GT(最终发芽率)。种子萌发实验是化感作用研究中最重要、应用最广泛的生物测定方法之一，应根据不同的研究目的合理采用指标和实验方法。2. 采用培养皿试纸法进行种子萌发试验，研究了香豆素水溶液在苜蓿种子萌发过程中对其吸水、电导率及抗氧化保护酶活性的影响。结果表明，影响苜蓿种子发芽的香豆素浓度阀值为0.3mM。香豆素在1.0mM 的浓度下降低了苜蓿种子吸水阶段Ⅱ的吸水速度，使其外渗物质增多，电导率增大，并显著抑制了超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性，同时种子体内丙二醛（MDA）的含量显著增大。高浓度香豆素破坏了膜的结构、影响了抗氧化保护酶的活性是香豆素降低苜蓿发芽率的原因之一，也可能是影响花椒-苜蓿间作的关键因素之一。3. 不同浓度（0、25 μM、50 μM、0.1 mM、1.0 mM）化感活性物质香豆素对10 日龄苜蓿幼苗初级氮同化的影响的结果表明25 µM～50 µM 的香豆素加快了苜蓿幼苗对硝态氮的吸收。高浓度的香豆素导致苜蓿根系和叶片内可溶性蛋白含量降低、鲜重减小、地下鲜重/地上鲜重（R/S）的比值升高，根系中初级氮同化的关键酶硝酸还原酶（NR）、谷氨酸胺合成酶（GS）、谷氨酸脱氢酶（GDH）的活性降低，叶片中NR、GS 的活性减低、叶绿素含量减少，而GDH 的活性升高。香豆素影响苜蓿幼苗氮代谢和氨同化的关键酶，导致体内养分的缺失是香豆素抑制苜蓿幼苗生长的机理之一。Coumarins are lactones of o-hydroxycinnamic acid, and are allelopathiccompounds that originate in the phenylpropanoid pathway. They are synthesized byalmost all higher plants. According to previous studies, coumarins were mostimportant allelochemicals in Chinese prickly ash. Systematically research of theeffect of coumarin could help to comprehend the continuous cropping impediment.The effects of coumarin on seed germination and primary nitrogen assimilation ofalfalfa were studied. The main results showed that:1. We compared four common germination indices (S, AS, CRG, GT)preciously calculated with the same date. The results showed that, at theconcentration of 1.0 mM, coumarin inhibited seeds germination. Among all indices,the S index was most sensitive, followed by the AS and CRG indices. Andsuggestions on the expression of bioassay results were also provided.2. At concentrations above 0.3 mM, coumarin inhibited seed germination in aconcentration-dependent manner. During seed imbibitionⅡ, coumarin at 1.0 mMsignificantly reduced the activities of superoxide dismutase (SOD), catalase (CAT),peroxidase (POD), while the content of malonyldialdehyde (MDA) in alfalfa seedssignificantly increased. The higher concentration coumarin destroyed structure ofmembrane and influenced activities of antioxidant enzymes, which might be one ofthe reasons that coumarin decreased germination rate of alfalfa, and one of the keyfactors influencing Chinese prickly ash-alfalfa intercropping.3. Alfalfa plants were exposed to different concentration of coumarin (0、25μM、50 μM、0.1 mM、1.0 mM) grown for 10 days on control medium. Coumarin, in the range of 25 μM～50 μM, significantly stimulated the net nitrate uptake.Increasing coumarin concentration led to a decrease of protein contents in theleaves and roots. The root to shoot (R/S) FW ratio was increased by increasingcoumarin concentration. Under high coumarin concentration, the activities of nitratereductase (NR) and glutamine synthetase (GS) were repressed in the roots andleaves. Glutamate dehydrogenase (GDH) was inhibited in the roots, while enhancedin the leaves. Chlorophyll contents in the leaves were also decreased under highcoumain concentration. Coumarin decreased alfalfa growth by (i) nutritionaldeficiencies shown by the decrease of nitrate, (ii) lowered N compound synthesisvia inhibition of nitrate reduction and ammonium assimilation.

水分梯度上不同灌木生长对干旱河谷土壤理化和生物学性质的影响

岷江上游干旱河谷区水土流失强烈，地质灾害频繁，生态环境十分脆弱，而土壤条件恶劣（水分不足和养分缺乏）是阻碍该区植被恢复的关键因子，因此研究水分和乡土灌木生长对土壤的影响对该区的生态恢复具有指导意义。本文通过定点模拟实验，选取三种优势豆科灌木为研究对象，分别是白刺花（Sophora davidii）、小马鞍羊蹄甲（Bauhinia faberi var. microphylla）和小雀花（Campylotropics polyantha），设置5 个水分梯度，分别为100%、80%、60%、40%和20%田间持水量（FC），对栽种植物与不种植物下土壤理化性质和酶活性进行测定分析，系统比较和研究了不同水分条件和不同乡土灌木生长对干旱河谷区土壤结构、养分循环、酶活性以及微生物量的影响。主要结果如下：1. 无论生长植物与否，土壤的毛管持水量和毛管孔隙度都随着水分含量的减少而降低，最大持水量、总孔隙度和容重变化不大，相应地，土壤中的非毛管孔隙随含水量的减少而升高。各水分条件下，种植植物的毛管持水量和毛管孔隙度低于无植物生长的土壤，非毛管孔隙度相应地高于无植物土壤。土壤含水量在100%－40% FC 时，三种豆科灌木的毛管持水量和毛管孔隙度存在差异，而20% FC 条件下，三种豆科灌木土壤的物理性质基本相同。2. 水分胁迫影响土壤中养分的矿化和积累，主要表现在降低了水溶性碳和铵态氮的含量，中等程度胁迫时（60% FC）促进了有机碳和硝态氮的富集，对速效钾和有效磷没有明显作用。种植豆科灌木后各水分梯度上都增加了有机碳、铵态氮、速效钾和有效磷的积累。增加程度上三种豆科灌木间有一定差异，对于土壤有机碳总量，种植白刺花和小马鞍羊蹄甲明显高于小雀花，同样的情况还出现在铵态氮和速效钾上，但是对于有效磷，种植小雀花后的增加程度则明显高于白刺花和小马鞍羊蹄甲。种植豆科灌木不仅增加了土壤养分的相对含量，也改变了其在水分梯度上的变化趋势及其变化幅度，这种作用主要体现在碳元素和氮元素上。3. 无植物生长时脲酶活性随水分含量的减少而升高，水分胁迫对磷酸酶和过氧化氢酶的作用不显著，蔗糖酶也保持在相对较高的水平。种植植物后，蔗糖酶、磷酸酶活性与无植物时相比有较大幅度的提高，种植白刺花的脲酶活性也升高，其升高的程度在不同水分含量时不同。种植植物还降低了酶活性在水分梯度上的变幅，使之在水分梯度间的差异显著性降低。脲酶活性在指示土壤性质改变方面是较敏感的指标，其它三种酶在不同植物间的差异不明显。4. 在无植物生长时，中等程度的水分胁迫（60% FC）提高了土壤微生物量碳含量，过高或过低的土壤水分均不利于微生物碳的积累。种植小马鞍羊蹄甲后微生物量碳在水分梯度上的变化趋势与无植物生长时一致，而种植白刺花和小雀花后微生物量碳随着水分含量的减少而降低。不同种类植物的微生物量碳在水分梯度上的变化特征也不同，100% FC 条件下三种植物间没有差异，80%和60% FC 条件下小马鞍羊蹄甲显著高于白刺花和小雀花，40%和20% FC 条件下白刺花和小马鞍羊蹄甲也显著高于小雀花，说明不同种类植物随着干旱胁迫程度的加深微生物量碳的降低幅度不同，在极度干旱时，白刺花和小马鞍羊蹄甲土壤依然保持了较高的微生物活性，而小雀花土壤微生物量则明显下降。The dry valley of the upper reaches of the Minjiang River is seriously degradedmountain ecosystem. It was endangered by extremely soil lost and frequentlygeological disaster. Previous studies showed that short of water and nutrients in soilwas the principal limiting factors of vegetation restoration in this area. The typical soiland three dominant leguminous shrubs Sophora davidii, Bauhinia faberi var.microphylla and Campylotropics polyantha in upper reaches of arid Minjiang Rivervalley were considered as experimental material. Two-month old seedlings of eachspecies were exposed to five water supplies (100%, 80%, 60%, 40% and 20% waterfield capacity (FC)) in a temperature and light-controlled greenhouse. Afterthree-month water treatment, soil physiochemical variables and soil microbialactivities were determined by conventional methods. The main results showed that:1. Soil capillary capacity and capillary porosity decreased along water supplyregimes in all treatments, while saturated water capacity, total porosity and bulkdensity kept in a relatively stable level, as a result, the non-capillary porosity andcapacity increased with decrease of water supply. Compared to non-planted soil, theplant-soil systems had a higher non-capillary porosity and capacity, suggestingappropriate oxygen was present in soil to maintain the living of microorganism. Soilof three type shrub species shared the same capillary capacity and capillary porosityunder 20% FC.2. Water soluble carbon and NH4+-N decreased in response to water stress, whiletotal organic carbon and NO3--N promoted by moderate water stress and inhibited by 100% and 20% FC. Total organic carbon, NH4+-N, rapidly available K and availableP increased after the planting of leguminous shrubs in five water supply regimescompared to non-planted soil. For TOC, NH4+-N and rapidly available K, thepromotion effect was higher in S. davidii and B. faberi var. microphylla than C.polyantha planted soil, while available P displayed the opposite side. The planting ofshrubs also reduced the variance of observed traits along water supply gradients.3. Drought stress increased urease activity in non-planted soil, while insignificantdifferences were observed in phosphatase and catalase activity among five watersupply regimes. The planting of leguminous shrubs facilitated the β-glucosidase andphosphatase activity compared to the non-planted soil. It also reduced the variance ofenzyme activity along water supply gradients. Urease was more sensitive to waterstress than other three enzymes.4. Soil water content significantly affected microbial biomass carbon andCmic:Corg. S. davidii and B. faberi var. microphylla showed more drought toleranceability than C. polyantha, attributing not only to their relatively smaller variance ofmicrobial biomass carbon along soil water supply gradients, but also to the highlevel of microbial activity under severe water stress. S. davidii and B. faberi var.microphylla benefited reproduction of soil microorganism at 60%-80% FC, whilesevere drought limited it due to the competition of water and nutrients between plantand soil microorganism.

青藏高原东缘川西云杉林皆伐后灌木生长、繁殖与更新的研究

植物群落及其环境在干扰后的演替格局和过程的研究，是群落和生态系统动态研究的一个热点。选取青藏高原东缘山原区川西云杉林皆伐后，从草地过渡到灌丛的关键阶段的4 个皆伐迹地（恢复时间为8 a、10 a、16 a 和21 a），研究皆伐及自然恢复过程对林下典型灌木银露梅（Potentilla glabra）和唐古特忍冬（Lonicera tangutica）的生长与繁殖能力的影响以及灌木植物在迹地上的更新情况，分析灌木在不同生境中的适应对策和适应能力的差异,为揭示青藏高原东缘山原区迹地植被从草甸到灌丛演替的过程和特点及促进迹地演替与植被恢复进程提供理论依据和技术支撑。研究主要结论如下：1）皆伐后银露梅生长和繁殖能力显著提高，但对唐古特忍冬的影响不明显。皆伐后银露梅丛基径、高度和各部分生物量都显著增加（P < 0.05），但唐古特忍冬只有叶生物量和地下生物量增加，总生物量和其余构件生物量无显著变化。皆伐后，银露梅的结实数量、结实株数、不结实株数和结实株/不结实株比例显著增加（P < 0.05）。自然恢复过程中，银露梅和唐古特忍冬生长能力以及银露梅的结实量都表现出降低的趋势。随着迹地自然恢复时间的增加，银露梅和唐古特忍冬的基径、高度、丛叶片数和各部分生物量有减少的趋势。银露梅的结实株数增加, 但结实数量减少。2）皆伐对银露梅和唐古特忍冬生物量分配模式影响不一致。原始林和迹地中（除CT85）银露梅的生物量大小关系皆为：地下>茎>侧枝>叶。唐古特忍冬在原始林中的生物量大小关系为：茎＞地下部分＞侧枝＞叶,而皆伐后生物量的分配情况改变，生物量大小关系变为：地下部分＞茎＞侧枝＞叶。随着自然恢复时间的增加，银露梅减少了地下生物量的分配，而唐古特忍冬增加了地下生物量的分配。3）皆伐和恢复时间的增加改变了迹地物种组成，促使阳性乔、灌木在迹地上定居。4 个迹地上共出现了灌木15 种，乔木3 种，没有出现天然云杉和冷杉幼苗。随着恢复时间的增加，迹地上的灌木物种由原始林下的耐阴物种逐步发展为以针刺悬钩子（Rubus pungens）为主的阳性灌木。4）影响灌木幼苗密度和幼树密度的因子不一致。灌木幼苗密度与灌木层盖度显著负相关，与苔藓层盖度显著正相关。幼树密度与草本层盖度正相关，与苔藓层盖度、灌木层盖度和高度负相关。5）研究发现在青藏高原东缘山原区皆伐15～20 a 后，迹地仍以草本植物为主，推测皆伐后至少20 a 以上迹地才可能向灌丛阶段过渡，比高山峡谷地区的演替进程至少推迟了20 a。银露梅和唐古特忍冬在皆伐后自然恢复过程中表现出不同的生长与繁殖策略是由两个物种的生物学特性的差异引起的。银露梅比唐古特忍冬更适应迹地退化环境。促进青藏高原东缘山原林区迹地森林恢复一方面是尽量减少人为活动的破坏，另一方面，可以通过在迹地中播种适当的乡土乔、灌木种子（如白桦、银露梅）等人工措施，以加快演替进程。The succession pattern and process of plant community and their environments is a hot spotin community and ecosystem dynamic study. Four clearcuts were chosen in Rangtang(recovery time of 8 a、10 a、16 a and 21 a), which represented the key stage of thecommunity evolved from grass stage to shrub stage in the eastern margin of theQinghai-Tibetan Plateau. The growth and reproduction of the Potentilla glabra andLonicera tangutica and the natural regeneration of shrub plants in the primary Piceabalfouriana forest and 4 clearcuts were studied to explore how clear cutting andnatural recovery process affected the understory shrub species during the 21 years inthe eastern margin of the Qinghai-Tibetan Plateau. The main results were below.1) The growth and reproduction of P. glabra significantly increased after forestclear cutting.. But it was not so significant as to the L. tangutica. The organismbiomass and total biomass of P. glabra were increased obviously after clear cutting（P< 0.05）. But only leaves and underground biomass of L. tangutica increasedsignificantly after clear cutting（P < 0.05）. The number of fruit and growth of P. glabraincreased significantly after clear cutting too（P < 0.05）. The ramet height, basaldiameter , organism biomass and friut number of P. glabra and L. tangutica reducedas the increase of recovery time.2) The biomass allocation patterns varied between P. glabra and L. tangutica inthe primary forest and clearcuts. The biomass allocation of P. glabra both in primary forest and clearcuts was followed as: underground part > stem > branch > leaves.However, the biomass allocation of L. tangutica had changed after the clear cutting.The biomass allocation of L. tangutica in the primary forest was followed as: stem >underground part > branch > leaves and it was underground part > stem > branch >leave in clearcuts. The biomass allocation of P. glabra and L. tangutica varied amongclearcuts. Aboveground biomass was increased while underground biomass decreasedfor P. glabra with the increase of recovery period. However, the L. tangutica showedthe reverse changing pattern.3) Clear cutting and recovery time had changed the species composition of theclearcuts. There were 15.shruby species and 3 tree species in the four clearcuts. Nospruce and fir seedlings were found. In the early stage after clear cutting, there wereonly understory shrub species from the primary Picea balfouriana forest. The sunnyspecies, especieally Rubus pungens invaded intensly as the increase of recovery time.4) There was a significant negative relationship between density of seedlingswith shrub layer coverage and positive correlation with moss coverage. The saplingshad significantly positive correlation with herb layer coverage and negativecorrelation with moss coverage, shrub layer coverage and height.5）Comparing to studies in Miyalou, a nearby high mountain and canyon area,the secondary sucession in this subalpine plateau areas lagged at least 20 years.P. glabra and L. tangutica showed different growth and reproduction strategies toclear cutting and natural recovery , which may associated with the difference of theirbiological characters. P. glabra was more adaptive to the clear cutting than the L.tangutica. Two suggestions were probably recommended to promote the recoveryprogress in the subalpine plateau areas based on the results of this study. Limitanthropogenic disturbance, and meanwhile sow native tree and shrub seeds inclearcuts.

模拟增温与UV-B 辐射增强对云杉种子萌发和幼苗生长的影响

臭氧层损耗导致的地球表面UV-B辐射增强以及温室气体增多引起的气候变暖是当今两大全球环境问题。UV-B辐射增强和气候变暖对陆地植物和生态系统产生深远影响，并已成为全球变化研究的重要议题。作为世界第三极的青藏高原，UV-B 辐射增强以及气候变暖现象尤为突出。本试验所在林区是青藏高原东缘的主要林区，具有大面积的亚高山人工针叶成熟林，在全球变化背景下该森林的天然更新潜力如何是急待回答的重要问题。基于此，本研究围绕森林树种的种子和幼苗这一更新的重要阶段，开展了气候变暖、UV-B辐射增强和联合胁迫对云杉种子萌发及幼苗定居影响的研究，旨在全球变化背景下，探讨全球变暖、UV-B 辐射增强和联合胁迫是否对西南地区大面积人工亚高山针叶林更新的种子萌发和幼苗定居阶段产生影响。 本文以青藏高原东缘亚高山针叶林主要树种云杉为研究对象，研究云杉种子萌发及幼苗的生长和生理对UV-B辐射增强与气候变暖的响应。采用UV-B荧光灯（UV-lamp）来模拟增强的UV-B 辐射，此外，采用开顶式有机玻璃罩（OTCs）来模拟气候变暖。本试验包括四个处理：（1）大气UV-B 辐射+大气温度（C）；（2）大气UV-B 辐射+模拟气候变暖（W）；（3）增强的UV-B辐射+大气温度（U）；（4）增强的UV-B辐射+模拟气候变暖（U+W）。 根据本试验结果，UV-B辐射增强对云杉种子萌发没有显著影响，它对萌发云杉幼苗的影响主要体现在幼叶展开以后。根据两年的试验结果，增强的UV-B辐射降低了云杉幼苗抗氧化酶活性，降低了抗氧化物质的含量，此外，造成了膜质的过氧化，表现为MDA在针叶中的积累。增强的UV-B照射处理萌发云杉幼苗两年后，幼苗的生长受到显著抑制。我们的结果显示，OTCs分别提高了空气（10 cm）和土壤（5 cm）温度1.74℃和0.94 ℃。增温显著地促进了云杉种子提前萌发，提高了萌发速率和萌发比率，而且，明显地促进了幼苗的生长，表现为株高和生物量累积的显著增长。此外增温还有利于云杉幼苗根的伸长生长以及生物量的累积，这可以使云杉幼苗更好地利用土壤中的水分和营养元素。 根据本试验结果，温度升高显著地促进了增强UV-B辐射下云杉萌发幼苗的生长，这说明，温度升高缓解了UV-B辐射增强对云杉萌发幼苗的负面影响。这种缓解作用可能是温度升高对UV-B辐射增强处理下幼苗的抗氧化系统活性改善的结果。温度升高还缓解了高UV-B辐射对云杉幼苗根生长的抑制作用，这也可能是增温缓解伤害的原因之一。此外，根据我们的试验结果，增温与UV-B辐射增强联合作用（U+W）下云杉萌发幼苗的生长状况好于大气温度与大气UV-B辐射联合（C）处理，表现为株高、地径、根长和生物量积累均高于C处理，因此可以推断，UV-B辐射增强与气候变暖同时存在对萌发幼苗在两年之内的生长没有产生抑制作用，也就是说，气候变暖的缓解作用完全弥补了UV-B辐射增强的有害作用。 同样，增强的UV-B辐射显著影响了云杉幼苗的光合作用，表现为净光合速率（Pn）和表观量子效率（Φ）的提高，此外，根据我们的试验结果，它还造成了PSII的光抑制。增强的UV-B辐射显著抑制了云杉幼苗对营养元素的吸收，表现为大量营养元素、碳、钙、镁和锌含量的降低，但是，它却显著促进了铁在植株体内的积累。增温显著地提高了净光合速率，但是，它对光系统II（PSII）的光化学效率影响不大。温度升高缓解了UV-B增强对云杉幼苗光合作用的伤害，表现为净光合速率、表观量子效率以及PSII光化学效率的提高。此外，温度升高还缓解了UV-B辐射增强对离子吸收的抑制作用。 Enhanced UV-B radiation due to the reduction of O3 layer and global warming induced by increased greenhouse gases in the air have become the two pressing aspects of global climate changes. Moreover, enhanced UV-B radiation and warming have profound and long-term impacts on terrestrial plants and ecosystems, and the studies focusing on the two factors have attracted many attentions. Qinghai-Tibetan Plateau is the third in elevation in the world, and enhanced UV-B radiation and climate warming are especially prominent in this region. Our research located in the main forest belt in the eastern Qinghai-Tibetan Plateau where large areas of subalpine coniferous forests distributed. Based on that, we carried out a research to study the effects of enhanced UV-B radiation and climate warming on seed germination and seedlings growth of seedlings which are the important basic stage in forest regeneration. This research was arranged by a complete factorial design and included two factors (UV-B radiation and temperature) with two levels. The UV-lamps were used to manipulate the supplemental UV-B radiation and open-top chambers (OTCs) were adopted to increase temperature. The four treatments were: (1) C, ambient UV-B without warming; (2) U, enhanced UV-B without warming; (3) W, ambient UV-B with OTCs warming; (4) U+W, enhanced UV-B with OTCs warming. The main results were exhibited as follows: 1. Based on our results in this research, OTCs increased temperature on average 1.74℃ in air (10 cm above ground) and 0.92 ℃ in soil (5 cm beneath ground). Furthermore, OTCs also slightly reduced soil moisture and relative air humidity, however, the differences was not statistically significant. 2. Our results showed that enhanced UV-B had no significant effects on the seeds germination of P. asperata. Enhanced UV-B affected sprouts of P. asperata until the needles unfolded. During two years, enhanced UV-B inhibited the efficiency of the antioxidant defense systems, and as a result, it induced oxidant stress and the accumulation of MDA in needles. After two years of exposure to enhanced UV-B, the growth of P. asperata sprouts was markedly restrained compared with those under ambient UV-B radiation and temperature (C). Warming significantly stimulated the germination speed and increased the germination rate of P. asperata seeds. In the next place, it prominently facilitated the growth of P. asperata sprouts, represented as improvements in stem elongation and biomass accumulation. Furthermore, warming also increased root growth of P. asperata sprouts, which could made sprouts more efficient to use water and nutrient elements in soil. In this research, warming alleviated the deleterious effects of enhanced UV-B on P. asperata sprouts. It markedly stimulated the growth of P. asperata sprouts exposed to enhanced UV-B. The ease effects of warming on the abilities of the antioxidant defense systems might account for its amending effects on growth. After two years of exposure to enhanced UV-B radiation and warming, the growth of P. asperata sprouts was better than those under ambient UV-B radiation without warming (C), which could be seen from the higher plant height, basal diameter, root length and total biomass accumulation compared with C. 3. Enhanced UV-B radiation significantly influenced the photosynthesis processes of two-year old P. asperata seedlings. Our results showed that enhanced UV-B reduced the net photosynthetic rate (Pn) and the apparent quantum efficiency (Φ), and induced photoinhibition of photosynthetic system II (PSII). Enhanced UV-B significantly decreased the concentration of nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg) and zinc (Zn), however, it increased the accumulation of iron (Fe) in the whole plant of P. asperata seedlings. Warming significantly stimulated Pn of P. asperata seedlings but it had no prominent impacts on the photochemical efficiency of PSII. In our research, warming also alleviated the harmful effects of enhanced UV-B on photosynthesis and absorption of ions of P. asperata seedlings. It increased Pn, Φ and the photochemical efficiency of PSII in seedlings exposed to enhanced UV-B. Moreover, warming also increased the absorption of ions of the seedlings exposed to enhanced UV-B radiation.

岷江柏种子的形态和发芽特征与贮藏生理动态研究

岷江柏(Cupressus chenggiana S. Y. Hu)是我国川甘地区特有的珍稀濒危乔木，一般生长在干旱的河谷区，在涵养水源和保护水 土等方面起着重要的作用。本文选择4个岷江柏种群，采用了野外调查和室内实验相结合的研究方法，调查岷江柏种群结实状况， 分析种子和球果形态特征，阐明种子发芽的基本特征，研究岷江柏种子贮藏过程中几个生理指标的动态变化特点，目的是为岷江柏 种苗繁育、自然更新能力评估以及珍稀濒危机制分析提供理论依据。研究得出如下结论：1.岷江柏球果呈椭球形，长为1.5～ 2.2cm,宽为1.5～1.9cm，质量为1.7～4.2g，球果鳞片数量为8～11片，球果内种子数量一般在40～70粒。岷江柏种子为椭圆形，长 为3.58～4.02mm，宽为3.10～3.15mm，厚为0.96～1.11mm，千粒重为3.1～3.5g。岷江柏的结实率很低，并且有显著的地理差异和 大小年差异。2. 岷江柏种子发芽温度范围是5℃～30℃,其中种子的适宜发芽温度范围是10℃～25℃。种子最适发芽温度随着贮藏 时间的增加而变化。在适宜温度范围内，种子发芽周期为20d。温度对种子的发芽势和T50有显著影响，对种子发芽率没有显著影响 ；光照有利于种子发芽；岷江柏种子的发芽特征是岷江柏保护种子资源、防止物种濒危的一种环境适应，有助于岷江柏种子提高发 芽率和幼苗的存活率。岷江柏种子是一种耐贮藏的正常性种子，在短期贮藏过程中，贮藏温度和种子含水量对于种子生理指标和种 子发芽没有显著影响。3. 岷江柏种子在短期贮藏过程中，千粒重没有显著变化；含水量都经历了先下降，再稳定的过程；粗脂肪 含量和可溶性糖含量逐渐降低；可溶性蛋白含量和丙二醛含量逐渐增加；脯氨酸含量在贮藏1～7个月时变化差异不明显，但是贮藏 7～10个月后显著增加。岷江柏种子的各个生理指标之间的相关性差异不显著。4. 岷江柏球果和种子的形态特征存在显著的地理差 异。岷江柏种子的发芽能力的地理性差异不大，种群间差异不大。岷江柏种群的地理差异由种群特征、生境特征和气候特征共同决 定。5. 在岷江柏的人工繁育中，对于刚刚采集的种子，发芽温度在15℃～25℃比较适合，其中以25℃最佳；而对于短期贮藏(4～ 10个月)后的种子，发芽温度在10℃～25℃均可，以15℃～20℃为最佳。野外播种的最适时间为4～6月，6～9月的间歇性干旱和降 水波动可能是限制岷江柏自然更新的因素之一。在短期贮藏过程中，种子可以采用常规室温贮藏，可以节约成本。Cupressus chenggiana is a specific and endangered plant in Sichuan and Gansu provinces of China, and it usually grows in dry valley and plays an important role in water supply and soil and water conservation in the dry valley of alpine and canyon region of southwest China. The research selected four Cupressus chenggiana populations and used the methods of the field investigation and the lab experiments. The fruiting characters of Cupressus chenggiana populations, the morphological characters of seeds and cones, the germination characters of seeds and the store physiological dymatics of several factors of seeds have been studied in order to give some theoretical advices on the artificial propagation and the ability of natural regeneration and the endangered principle of Cupressus chenggiana in the paper. The main results may be clarified as follows: 1. The cones of Cupressus chenggiana are ellipsoidal, length ranged from 1.5 to 2.2cm, with ranged from 1.5 to 1.9 cm, weight ranged from 1.7 to 4.2g, the number of cone squama ranged from 8 to 11, and the seed number of per cone ranged from 40 to 70. The seeds of Cupressus chenggiana are elliptical, length ranged from 3.58 to 4.02 mm, width ranged from 3.10 to 3.15 mm, thickness ranged from 0.96 to 1.11 mm, and the weight of 1000 seeds ranged from 3.1 to 3.5g. The fruiting rate of Cupressus chenggiana is very low, and the fruiting period of Cupressus chenggiana has the geographical differences and the big or small year differences. 2. Seed germination temperature is between 5℃ and 30℃, while the suited temperature is between 10℃ and 25℃. The optimum temperature of seed germination will change as the store time of seeds changes logner. The cycle of seed germination can persist 20 days in the range of the suited temperature. The germination temperatures have significant influences on the germination potential and T50, but have no significant infuluences on the germination rate. The photoperiod is in favor of seed germination. The characters of Cupressus chenggiana seed germination represent a kind of environmental adaptability to protect the seed sources and endangered species, and it can give help to increase the germination rate of seeds and the livability of seedings. The seeds of Cupressus chenggiana are a kind of orthodox seeds that can endure the long time storage. In the short time storage, the store temperatures and the moisture contents of seeds have no significant infuluences on the physiological factors and the germination of seeds, but the store time has significant influences on the physiological factors of seeds. 3. In the short store course of Cupressus chenggianna seeds, the 1000 seed weight has no significant variation; The moisture content descends at the beginning of the storage, but has no significant variation later; The crude fat content and the soluble sugar content descend gradually; The soluble protein content and MDA content increase gradually; The praline content has no significant variation after 1～7 months storage, but increase significantly after 7～10 months storage. The correlations of different physiological factors are not significant. 4. The morphological characters of cones and seeds of four populations exist significant differences. The germination of Cupressus chenggiana seeds has no significant geographical variation. The geographical variation of Cupressus chenggiana populations can be ascribed to the population characters, climate and environment. 5. In the course of artificial propagation of Cupressus chenggiana, it is favored that the germination temperature of newly collected seeds is between 15℃ and 25℃, while the optimum temperature is 25℃. After the short storage ranged from 4 months to 10 months, it is favored that the germination temperature is between 10℃ and 25℃, while the optimum temperature is ranged from 15℃ to 20℃. The field sowing optimum time is between April and June, and the interval drought and fallrain fluctuation between July and September may be one of the reasons that restrict natural regeneration of Cupressus chenggiana. In the short storage, seeds can be stored in the condition of room temperature.

岷江干旱河谷三种蔷薇植物繁殖更新研究

繁殖更新是植物生活史的重要阶段，在退化生态系统中，植物繁殖更新能力往往较差，是植被恢复的限制环节，因而也成为恢复研究重点和核心。本研究选择岷江干旱河谷广泛分布的三种蔷薇：多苞蔷薇（R. multibracteata）、黄蔷薇（R. hugonis）和川滇蔷薇（R. soulieana）为研究对象，通过野外调查，在查明其生长、繁殖更新状况的基础上，采用控制和模拟实验，对种子和幼苗阶段进行了深入研究，综合分析更新潜力，并提出相对应的促进更新和植被恢复措施。主要结论如下： 1）三种蔷薇在岷江干旱河谷广泛分布，生长和繁殖状况良好，结实量大。各生长指标：株高、基径和冠幅，繁殖指标：结实数量、重量和单果重量都具有显著的空间差异性。基径对多苞蔷薇结实量影响最大；而冠幅对黄蔷薇结实量影响最大。海拔和纬度是对蔷薇生长和繁殖影响最大的环境因素，随着海拔和纬度的升高，植株生长更高大，结实量增加；坡度和坡向对其生长和繁殖也有一定影响，随着坡度 和坡向增加，蔷薇生长和结实受到抑制。 2）三种蔷薇在岷江干旱河谷更新现状不佳, 但更新潜力大。活力种子比率低，动物取食以及两年生幼苗的大量死亡是蔷薇更新的主要限制因素。多苞蔷薇和黄蔷薇的结实率低，川滇蔷薇较高。三种蔷薇种子产量大，但种子质量较差，更新具有充足的种源。三种蔷薇都能形成持久种子库，种子库中种子总量大，但有效种子少，黄蔷薇被动物啃食的比例很高，多苞蔷薇和川滇蔷薇也有一部分种子受到动物破坏。三种蔷薇幼苗库组成特征表现为，当年生幼苗所占比例很高，年龄较大幼苗所占比例小。 3）三种蔷薇都具有不同程度休眠，未经处理种子的发芽率极低。黄蔷薇休眠程度最深，为深度生理休眠；多苞蔷薇为中度生理休眠；川滇蔷薇为非深度生理休眠。三种蔷薇种子在形态上发育成熟，种皮具有透水性。蔷薇果果肉和瘦果中含有抑制物质，其浸泡液抑制了油菜种子萌发，果肉抑制作用更强，果肉和瘦果浸泡液的抑制程度分别为：川滇蔷薇>黄蔷薇>多苞蔷薇。切割和硫酸腐蚀提高了川滇蔷薇种子的发芽能力，而对多苞蔷薇和黄蔷薇没有影响。完全去除瘦果果皮和种皮提高了多苞蔷薇种子发芽率，但对黄蔷薇没有影响。赤霉素和烟水对蔷薇种子萌发没有促进作用。三种蔷薇打破休眠所需低温层积时间分别为：黄蔷薇>多苞蔷薇>川滇蔷薇。对于多苞蔷薇和川滇蔷薇，层积前对种子进行硫酸腐蚀或暖温层积能缩短低温层积时间，提高发芽率。对于多苞蔷薇，变温层积中暖温层积和低温层积具有一定的负补性，即延长暖温层积可以缩短种子萌发对低温层积的需要。 4）多苞蔷薇种子形态特征和种子休眠与萌发在不同海拔梯度间存在较大差异。种子采集时间、采集季节和干藏影响多苞蔷薇和川滇蔷薇的种子休眠。多苞蔷薇果实大小、种子大小和千粒重、种皮厚度随海拔升高而增加，而种子饱满率和活力随海拔升高而降低，种子休眠程度也随海拔升高而增加。种皮厚度与种子大小、千粒重成正相关关系，硫酸腐蚀后的种子经过不同时间的低温层积后，种子发芽率与种皮厚度、种子大小、千粒重、海拔成正相关关系。2006 年采集川滇蔷薇和多苞蔷薇种子休眠程度较2005 年低。种子休眠随种子年龄增加而减弱。高温和干旱能减轻多苞蔷薇和川滇蔷薇种子休眠。 5）三种蔷薇的生长和生物量积累在干旱胁迫条件下受到抑制，而生物量分配、叶片形态特征和水分利用特征等都发生了变化。三种蔷薇的根、茎、叶各器官生物量以及总生物量等在干旱胁迫下明显减小，叶片脱落数量增加。在干旱胁迫条件下，较多的生物量分配到地下部分，从而这使R/S 明显增加。比叶面积（SLA）和冠层面积比（LAR）对干旱胁迫的反应不敏感，仅有部分物种在干旱胁迫条件下发生了变化，并且其变化特点在不同年龄幼苗之间有一定差异。干旱胁迫对WUE 的影响在不同物种间存在差异。多苞蔷薇和黄蔷薇的WUE 随着干旱胁迫的增加而增大， 而川滇蔷薇的WUE 则随干旱胁迫增加而减小。在干旱胁迫条件下，多苞蔷薇和黄蔷薇叶片脱落量和生物量减小幅度较川滇蔷薇大，表明其抗旱能力较强。在干旱胁迫条件，三种蔷薇两年生幼苗的生物量减小幅度较当年生幼苗小，表明两年生幼苗的抗旱能力更强。 6）两种植被恢复措施中，幼苗移栽比播种具有更好的植被恢复效果。播种后，蔷薇种子的发芽率较高，但出苗率都很低，即使出苗，幼苗也几乎在一月内全部死亡。 三种微生境条件下（灌木、半灌木和裸地），种子出苗和幼苗成活没有差异。移栽幼苗总体死亡率都比较低，小于20％。特别是两年生幼苗死亡率更低，小于2％。移栽后的幼苗生长状况良好，在整个生长季中，各生长指标不断增加。生境对幼苗的存活率没有显著影响，但对于幼苗的生长和生物量积累有一定影响，裸地更有利于幼苗生长和生物量积累。与当年生幼苗相比，两年生幼苗具有更高的成活率。总之，三种蔷薇在干旱河谷分布广泛、生长繁殖状况良好，结实量大，具有丰富种源，繁殖更新潜力大，但繁殖更新状况不佳；种子散布后动物对种子的取食、种子的深度休眠过程、种子出苗以及当年生幼苗的存活和定居是更新的主要限制环节。水分是影响结实、种子休眠解除和萌发，幼苗存活和定居的最主要的限制因素。在植被恢复中，应在种子成熟季节大量采集种子，在室内打破休眠后进行人工播种，培育两年生幼苗，通过幼苗移栽方式进行植被恢复。川滇蔷薇应栽种在相对湿润的过渡区，而多苞蔷薇和黄蔷薇可以应用于核心区植被恢复。 Regeneration is an important phase in plant life cycle. It has been a key component of ecological restoration in degradation ecosystem in which plants commonly has poor regeneration. In this paper, we investigated the natural growth, propagation and regeneration status of native three rose species, Rosa multibracteata, R. hugonis and R. soulieana, and analysis the limitation in seed germination and seedling establishment stages. Advice on facilitating the use of these plants in restoration based on the results has been proposed. The results were as follows: 1) Three rose plants widely distributed in the dry valley of the Minjiang River, and made a good performance in growth and propagation. There were significant spatial differences in each growth parameter, such as ramet height, basal diameter, crown diameter and propagation parameters including hip number of a clump, hip mass of a clump and a hip mass. Basa diameter was the most important growth parameter influencing fruit number for R. multibracteata and crown diameter was for R. hugoni. Altitude and latitude had the greatest effect on the growth and propagation of rose plants among environmental conditions. Each parameter of growth and propagation increased with the increase of altitude and latitude. In addition, the increase of slope and aspect limited the growth and propagation. 2) Three rose plants had poor natural regeneration, but great regeneration potential. Low seed viability, predation and higher mortality of current year old seedlings were the limitation in regeneration. R. multibracteata and R. hugonis had higher fruiting rates than R. souliean. All three plants produced a great number of seeds, while their viability was poor. Three rose plants had persistent seed banks, with high total seed number but very low viable seed density. Predation was most severe in R. hugonis, and it also existed to some degree in R. multibracteata and R. soulieana. The seedling age-structure was characteristic of current-year seedlings predominating and few older seedlings were observed. 3) Three rose seeds were dormant and untreated seeds germinated with very low germination percentages. The rose seeds had morphological mature embryos, and achenes were permeable. Some inhabit substances existed in hips and achenes for the extracts of hips and achenes inhibited germination of Brassica campestris. The inhibition effect of the extracts of three rose hip and achenes was R. soulieana>R. hugonis>R. multibracteata. Mechanical and H2SO4 scarification increased R. soulieana germination but had no effect on germination of R. hugonis and R. multibracteata seeds. Full removal of pericarp and testa improved the germination of R. multibracteata but did not affect R. hugonis germination. GA3 and smoke water had no positive effect on rose seed germination. The periods of cold stratification required to released seed dormancy was R. hugonis > R. soulieana >R. multibracteata. H2SO4 scarification and warm stratification shortened cold stratification to release dormancy for R. soulieana and R. multibracteata. Warm stratification had complementary effect for cold stratification, i.e. the longer warm stratification seeds received, the shorter cold stratification were required to obtain the same germination percentage. Three rose seeds had different kinds of dormancy; R. hugonis has deep physiological dormancy, R. multibracteata with intermediate physiological dormancy and R. souliean non-deep physiological dormancy. 4）The seeds traits and dormancy of R. multibracteata showed significant difference across altitudes. Year and season of seed collection had significant effect on seed dormancy for both R. souliean and R. multibracteata. Hip size, seed size, seed weight, seed coat thickness and seed dormancy level increased with the increase of the altitude. There were positive relations between seed coat thickness with seed size and seed weight. Germination percentage of seeds treated with H2SO4 scarification following different periods of cold stratification showed positive relation with seed coat thickness, seed size, seed weight and altitude. Seeds of R. souliean and R. multibracteata collected in 2006 had low dormancy level than those collected in 2005. Seed dormancy decreased with increasing seeds age. High temperature and drought were associated with low dormancy level. 5) Seedling growth, the total dry mass and their components of seedlings were reduced, while leaf senescence accelerated under drought stress. More biomass allocation to root system resulted in higher R/S ratio under drought. Water-use efficiency (WUE) of R. multibracteata and R. hugonis increased, while it declined for R. soulieana under drought stress. R. soulieana seedlings had poor drought-resistance capacity it had more senescent leaves, and its reduction of biomass was stronger than two other rose plants under drought. The reduction degree of one year old seedlings under drought stress was slighter than that of current year seedlings. Therefore, one year old seedling was more drought-resistent compared to current year seedlings. 6）Planting seedlings may have better effect in comparison with direct seeding. Most seeds germinated after seeding, but seedling emergence was very low. More than 80 % seedlings from direct seeding died within a months after emergence. Seedling emergence and survival rate did not show difference among microhabitats. Mortality rates of seedlings artificially planted in microhabitats were general lower than 20 %, and the mortality rate of one year old seedlings was lower than 2 %. Each grow parameter including plant height, leaf number and branch number continually increased after planting. Microhabitat type had effect on the growth parameter and biomass production, but it did not influence the seedling survival. Bare land tended to facilitate seedling growth. One year old seedlings had higher survival rate than current year seedlings. In conculsion, the three rose had wide distribution in the dry valley of the Minjiang River. They produced many seeds and had tolerance to drought stress to some degree. But they had poor regeneration in habitats may be caused by predation, seed dormancy，and high mortality in current year seedlings. We recommend that rose plants should be utilized in restoration by planting two-year old seedlings in spring. A large quantity of seeds should be collected artificially in autumn, release seed dormancy in room, and then cultivate two-year old seedlings by seeding in particular container. R. soulieana seedling probably be planted in transition area, and R. multibracteata and R. hugonis can be used in core area of the dry valley of the Minjiang River.