Performance of an improved logarithmic phase mask with optimized parameters in a wavefront-coding system

In two papers [Proc. SPIE 4471, 272-280 (2001) and Appl. Opt. 43, 2709-2721 (2004)], a logarithmic phase mask was proposed and proved to be effective in extending the depth of field; however, according to our research, this mask is not that perfect because the corresponding defocused modulation transfer function has large oscillations in the low-frequency region, even when the mask is optimized. So, in a previously published paper [Opt. Lett. 33, 1171-1173 (2008)], we proposed an improved logarithmic phase mask by making a small modification. The new mask can not only eliminate the drawbacks to a certain extent but can also be even less sensitive to focus errors according to Fisher information criteria. However, the performance comparison was carried out with the modified mask not being optimized, which was not reasonable. In this manuscript, we optimize the modified logarithmic phase mask first before analyzing its performance and more convincing results have been obtained based on the analysis of several frequently used metrics. (C) 2010 Optical Society of America

Study on Mechanics Parameters of Unloaded Rock Mass about the Underground Powerhouse of Jin-ping Hydroelectric Station

After the excavation of Jinping underground cavern, a strong expansion appears along the unloading direction of the rock mass, mainly in the type of tensile rupture, accompanied by shear destruction, unloading resulted in significant deterioration of mechanical properties of rock. Based on the in-site investigation of rock mass structure, via analyzing the acoustic testing data, we identify the unloading range of the side walls and the division of rock types, and carry out with the solution of rock mechanical parameters about different unloading zone, providing geological foundation for the supporting design of the following design of the side walls, at the same time, providing reference for the selection of mechanical parameters of other underground excavation engineering with similar geological conditions.

水分亏缺和凋落物水浸液对云杉幼苗生长和种子萌发的影响

在人类活动导致全球变暖的前提下，由于全球气温的升高，地表水分加速向空中蒸发。从20世纪70年代至今，地球上严重干旱地区的面积几乎扩大了一倍。这一增长的一半可归因于气温升高而不是降雨量下降，因为实际上同期全球平均降水量还略有增长。干旱对陆地植物和农林生态系统产生深远影响，并已成为全球变化研究的一个重要方面。位于青藏高原东部的川西亚高山针叶林是研究气候变暖对陆地生态系统影响的重要森林类型。森林采伐迹地、人工林下和林窗环境作为目前该区人工造林和森林更新的重要生境，其截然不同的光环境对亚高山针叶林更新和森林动态有非常重要的影响。凋落物产生的化感物质可通过影响种子萌发和早期幼苗的定居而影响种群的建立和更新，而人工林和自然林物种以及更新速度的差异性也都受凋落物的影响。 云杉是川西亚高山针叶林群落的重要树种之一,在维持亚高山森林的景观格局和区域生态安全方面具有十分重要的作用，其自然更新能力及其影响机制一直是研究的热点问题。本试验以云杉种子和2年生幼苗为研究对象，从萌发、根尖形态、幼苗生长、光合作用、渗透调节和抗氧化能力等方面研究了不同光环境下水分亏缺和凋落物水浸液对云杉种子和幼苗生长的影响。旨在从更新的角度探讨亚高山针叶林自然更新的过程，其研究成果可在一定程度上为川西亚高山针叶林更新提供科学依据，同时也可为林业生产管理提供科学指导。主要研究结论如下： 水分亏缺在生长形态、光合作用、抗氧化能力、活性氧化对云杉幼苗都有显著影响。总体表现为，水分亏缺导致了云杉幼苗的高度、地径、单株总生物量降低，增加了地下部分的生长；水分亏缺显著降低了云杉叶片中相对含水量、光合色素、叶氮含量，净光合速率和最大量子产量(Fv/Fm)，提高了幼苗叶片中膜脂过氧化产物（MDA）的含量；水分亏缺提高了幼苗叶片中过氧化氢(H2O2)含量，超氧荫离子（O2-）生成速率以及脯氨酸和抗氧化系统的活性（ASA, SOD, CAT, POD, APX和GR）。从这些结果可知，植物在遭受水分亏缺导致的伤害时，其自身会形成防御策略，并通过改变形态和生理方面的特性以减轻害。但是，这种自我保护机制依然不能抵抗严重水分亏缺对植物的伤害。 模拟林下低光照条件显著增加单株植物的地上部分生长，尤其是其叶片的比叶面积（叶面积/叶干重），同时其光合色素含量和叶片相对含水量也显著增加，这些改变直接导致植株光合速率和生物量的增加。同时，与高光照水平相比，低光照幼苗的膜脂过氧化产物（MDA）和活性氧物质均较低，显示出低光照比高光照水平对植物的更低的氧化伤害。尽管低光照也导致大部分抗氧化酶活性降低，但这正显示出植物遭受低的氧化伤害，更印证了前面的结论。 凋落物水浸液影响了云杉种子的萌发和根系的生长，更在形态、光合作用、抗氧化能力、活性氧物质以及叶氮水平上显著影响了云杉幼苗，其中，以人工纯林凋落物的影响更有强烈。具体表现在，种子萌发速率和萌发种子幼根的长度表现为对照>自然林处理>人工纯林；凋落物水浸液抑制种子分生区和伸长区的生长，人工林处理更降低了根毛区的生长，使根吸水分和养分困难。对2年生幼苗的影响主要表现在叶绿素含量、光合速率以及叶氮含量的降低；膜脂过氧化产物、活性氧物质和抗氧化酶系统的显著增加。同样的，人工纯林处理对云杉幼苗的影响显著于自然林处理。 在自然生态系统中，由于全球变暖气温升高导致的水分亏缺和森林凋落物都存在森林的砍伐迹地，林窗和林下环境中。我们的研究表明，与迹地或林窗强光照比较，林下的低光照环境由于为植物的生长营造了较为湿润的微环境，因此水分亏缺在林下对云杉幼苗造成的影响微弱。这可以从植物的形态、光合速率以及生物量积累，过氧化伤害和抗氧化酶系统表现出来。另一方面，凋落物水浸液在模拟林下低光照环境对植物的伤害也微弱于强光照环境，这与强光照环境高的水分散失导致环境水分亏缺有关；而人工纯林处理对云杉幼苗的伤害比对照和自然林处理显示出强烈的抑制作用。 Under the pre-condition of global warming resulted from intensive human activities, water in the earth’s surface rapidly evaporates due to the increase of global air temperature. From 1970s up to now, the area of serious drought in the world is almost twice as ever. This increase might be due to the increasing air temperature and not decreasing rainfall because global average rainfall in the corresponding period slightly is incremental. Drought will have profound impacts on terrestrial and agriculture-forest system and has also become the important issue of global change research. The subalpine coniferous forests in the eastern Qinghai-Tibet Plateau provide a natural laboratory for the studying the effects of global warming on terrestrial ecosystems. The light environment significantly differs among cutting blanks, forest gap and understory, which is particularly important for plant regeneration and forest dynamics in the subalpine coniferous forests. Picea asperata is one of the keystone species of subalpine coniferouis forests in western China, and it is very important in preserving landscape structure and regional ecological security of subalpine forests. The natural regeneration capacities and influence mechanism of Picea asperata are always the hot topics. In the present study, the short-term effects of two light levels (100% of full sunlight and 15% of full sunlight), two watering regimes (100% of field capacity and 30% of field capacity), two litter aqueous extracts (primitive forest and plantation aqueous extracts) on the seed germination, early growth and physiological traits of Picea asperata were determined in the laboratory and natural greenhouse. The present study was undertaken so as to give a better understanding of the regeneration progress affected by water deficit, low light and litter aqueous extracts. Our results could provide insights into the effects of climate warming on community composition and regeneration behavior for the subalpine coniferous forest ecosystem processes, and provide scientific direction for the forest production and management. Water deficit had significant effects on growth, morphological, physiological and biochemical traits of Picea asperata seedlings. Water deficit resulted in the decrease in height, basal diameter, total biomass and increase in under-ground development; water deficit significantly reduced the needle relative water content, photosynthetic pigments, needle nitrogen concentration, net photosynthetic rate and the maximum potential quantum yield of photosynthesis (Fv/Fm), and increased the degree of lipid peroxidation (MDA) in Picea asperata seedlings; water deficit also increased the rate of superoxide radical (O2-) production, hydrogen peroxide (H2O2) content, free proline content and the activities of antioxidant systems (ASA, SOD, POD, CAT, APX and GR) in Picea asperata seedlings. These results indicated that some protective mechanism was formed when plants suffered from drought stress, but the protection could not counteract the harm resulting from the serious drought stress on them. Low light in the understory significantly increased seedling above-ground development, especially the species leaf area (SLA), and photosynthetic pigments and relative needle content. These changes resulted in the increase in net photosynthetic rate and total biomass. Moreover, the lower MDA content and active oxygen species (AOS) (H2O2 and O2-) in low light seedlings suggested that low light had weaker oxidative damage as compared to high light. Lower antioxidant enzymes activities in low light seedlings indicated the weaker oxidative damage on Picea asperata seedlings than high light seedlings, which was correlative with the changes in MDA and AOS. Litter aqueous extracts affected seed germination and root system of Picea asperata seedlings. Significant changes in growth, photosynthesis, antioxidant activities, active oxygen species and leaf nitrogen concentration were also found in Picea asperata seedlings, and plantation treatment showed the stronger effects on these traits than those in control and primitive forest treatment. The present results indicated that seed germination and radicle length parameters in control were superior to those in primitive forest treatment, and those of primitive forest treatment were superior to plantation treatment; litter aqueous extracts inhibited the meristematic and elongation zone, and plantation treatment caused a decrease in root hairs so as to be difficult in absorbing water and nutrient in root system. On the other hand, litter aqueous extracts significantly decreased chlorophyll content, net photosynthetic rate and leaf nitrogen concentration of Picea asperata seedlings; MDA, AOS and antioxidant system activities were significantly increased in Picea asperata seedlings. Similarly, plantation treatment had more significant effect on Picea asperata seedlings as compared to primitive forest treatment. In the nature ecosystem, water deficit resulted from elevating air temperature and litter aqueous extract may probably coexist in the cutting blank, forest gap and understory. Our present study showed that water deficit had weaker effects on low light seedlings in the understory as compared to high light seedlings in the cutting blank and forest gap. The fact was confirmed from seedlings growth, gas exchange and biomass accumulation, peroxidation and antioxidant systems. This might be due to that low light-reduced leaf and air temperatures, vapour-pressure deficit, and the oxidative stresses can aggravate the impact of drought under higher light. On the other hand, litter aqueous extracts in the low light had weaker effects on the Picea asperata seedlings than those at high light level, which might be correlative to the water evapotranspiration under high light. Moreover, plantation litter aqueous extracts showed stronger inhibition for seed germination and seedling growth than control and primitive forest treatments.

生姜化感作用机理及其栽培模式研究

近年来，随着对作物重茬（连年种植）障碍原因的深入研究，植物的化感作用越来越受到国内外众多学者的重视。而作为重要调料和药用植物的生姜，其连作障碍也备受关注，系统地研究生姜化感作用将有助于理解和最终解决生姜连作障碍问题。本文通过研究生姜不同部位、不同浓度的水浸液对与其间作的两个物种（大豆和四季葱）种子的萌发及幼苗生长的影响，从而证明生姜化感作用的存在；并通过温室盆栽实验研究了生姜的自毒作用（即研究生姜不同部位、不同浓度的水浸液对其幼苗的形态、生理生化、光合作用、土壤酶、土壤微生物多样性及土壤养分的影响），从而揭示生姜退化和衰老的机制，并为生姜筛选出合适的间作物种提供科学依据，对生姜连作障碍提出科学的解决方法。主要研究结果如下： 1. 与对照相比，生姜所有部位（根茎、茎、叶）、所有浓度（10、20、40、 80 g l-1）的水浸液均抑制了大豆种子和葱籽的萌发率、幼苗生长、水分吸收和脂肪酶活性，并且其抑制程度随着水浸液浓度的增加而增强，其生姜各部位水浸液抑制效应的强弱顺序为茎＞叶＞根茎。这一结果表明生姜根茎、茎、叶含有能够抑制大豆种子和葱籽种子萌发和幼苗生长的水溶性化感物质。根茎是生姜的主要收获部位，而生姜的残株（主要是茎和叶）应该从大田中处理掉以减轻其抑制效应。生姜水浸液中主要化感成分包括：根茎水浸液中主要是丁香酸和伞花内脂；茎水浸液中主要是阿魏酸，且其含量最高为73.4 ug/g；叶水浸液中除了阿魏酸，其他六种物质均检测出来，但含量较高的主要有丁香酸、伞花内脂和香豆酸。 2. 生姜茎和叶不同浓度的水浸液均显著抑制了生姜幼苗的株高、每株叶片数和叶面积，其抑制程度随着水浸液浓度的增加而有所增强，而生姜幼苗每株分枝数差异不显著；同时生姜水浸液也极大程度地影响了生姜幼苗的生物量（包括地下生物量、地上生物量和总生物量，均为鲜重）。在同一浓度下，茎水浸液对生姜幼苗形态指标及生物量指标均显示出最强的抑制作用，叶水浸液次之，根茎水浸液最弱。与对照相比，低浓度的生姜根茎水浸液提高了生姜幼苗叶片内四种抗氧化酶（SOD、POD、CAT、APX）活性，高浓度的根茎水浸液抑制了四种抗氧化酶活性，而茎和叶水浸液均随着浓度的增加而抑制了四种抗氧化酶活性，三种水浸液均随着浓度的增加降低了生姜幼苗叶片内叶绿素的含量，而增加了生姜幼苗叶片的相对电导率和丙二醛含量。同时，三种水浸液均随着浓度的增加降低了生姜幼苗的光合参数（包括胞间CO2浓度、气孔导度、蒸腾速率及净光合速率）。 3. 三种生姜水浸液对所测六种土壤酶活性均产生了不同程度的影响，其中影响最大的是酸性磷酸酶和蔗糖酶，在10 g l-1 时就达到了显著水平，并且所有酶均有随着水浸液浓度增加而增大的趋势；相同部位的水浸液随着浓度的增加，细菌和真菌的数量呈增加趋势，而放线菌的数量呈减少趋势；三种生姜水浸液均随着浓度的增加降低了土壤中有机质的含量，加剧了土壤中硝态氮含量的积累，根茎水浸液对土壤有效磷、速效钾和铵态氮均显示出低浓度提高其含量而高浓度降低其含量的趋势，而茎和叶水浸液则随着浓度的增加均降低了其含量。 4. 与生姜单作相比，所有间作系统均在旺盛生长期和收获期不同程度地提高了土壤酶活性，同时也增加了土壤细菌数量及土壤微生物总数但不显著；所有间作系统在旺盛生长期和收获期均不同程度地影响了土壤真菌及放线菌数量（增加或减少），所有间作系统间的多样性指数差异不显著，除了旺盛生长期四种作物（生姜-大豆-四季葱-大蒜）的间作模式显著降低了多样性指数，其值仅为生姜单作的33.18%；生姜与大豆间作不仅提高了19.6%的生姜产量而且获得了较好的经济效益，并且，所有间作系统均显著抑制了生姜姜瘟病的发生。 5. 不同栽培模式不同程度地影响了收获期生姜的株高、分枝数、根茎产量及内在品质。其中处理2显著地促进了生姜的分枝（10.5%），同时处理2、3和4也促进了生姜的生长（株高分别增加了15.0%、11.4%和14.0%），并且这三个处理提高了生姜的产量；处理2和3能有效提高生姜块茎中维生素C（分别较单作生姜显著提高了3.29%和4.05%）、处理3显著提高了可溶性糖（8.2%）、姜辣素（4.6%）和蛋白质等有益物质的含量，降低硝酸盐有害物质的含量（处理2显著降低了14.0%），改善了姜块的外观和内在品质。并且，生姜与大豆间作具有最高的纯收入和产投比，分别较生姜单作提高了24.80%和8.8%。Recently, allelopathy has been more and more paid attentions by national and foreign scholars with profound research on reasons of crop replanted (continuous planted) obstacle. Ginger rhizome is valuable all over the world either as a spice or herbal medicine and ginger replanted obstacle is also paid attentions. Systematic research on ginger allelopathy will contribute to understanding and ultimate solving problem of ginger replanted obstacle. The effects of ginger aqueous extracts with different parts and concentrations on seed germination and early seedling growth of soybean and chive were studied in this article to testify that ginger existed allelopathy. Furthermore, ginger autotoxicity was also studied by pot experiment in greenhouse (namely research on effects of ginger aqueous extracts with different parts and concentrations on morphological indexes, physiological and biochemical indexes, photosynthesis, soil enzymes, soil microbial diversity and soil nutrients) to reveal mechanism of ginger degeneration and senescence, provide scientific basis for selecting appropriate intercropping species and put forward scientific resolvent for ginger replanted obstacle. The main results were as follows: 1. All aqueous extracts at all concentrations inhibited seed germination, seedling growth, water uptake and lipase activity of soybean and chive compared with the control, and the degree of inhibition increased with the incremental extracts concentration. The degree of toxicity of different ginger plant parts can be classified in order of decreasing inhibition as stem＞leaf＞rhizome. The results of this study suggested that rhizome, stem and leaf of ginger contained water soluble allelochemicals which could inhibit seed germination and seedling growth of soybean and chive. The rhizome is the main harvested part of ginger. The residue (mainly stems and leaves) of the ginger plant should be removed from the field so as to diminish its inhibitory effect. The main allelopathic components of three kind of aqueous extracts were as follows: Rhizome extract chiefly contained syringic acid and vmbelliferone and stem extract mainly contained frulic acid whose content was the highest (73.4 ug/g). The other six substances were detected except of frulic acid, but only contents of syringic acid, vmbelliferone and p-coumaric acid were higher. 2. Stem and leaf aqueous extracts of ginger with different concentrations significantly inhibited plant height, leaf numbers per plant and leaf area, and the degree of inhibition increased with the incremental extracts concentration. However, tiller number per plant of ginger seedling showed no significant difference. At the same time, ginger aqueous extracts also influenced biomass including under-ground biomass, above-ground biomass and total biomass (fresh weight) to a large extent. Under the same concentration, stem aqueous extract showed the mostly inhibitory effect on morphological indexes and biomass indexes of ginger seedling. Rhizome aqueous extract showed the leastly inhibitory effect and leaf aqueous extract was intervenient. Enhanced concentration of ginger aqueous extracts significantly reduced total chlorophyll content, accompanying with increases in memberane permeability (REL) and lipid peroxidation (MDA). Compared with the control, rhizome ginger aqueous extract of lower concentration (10 g l-1) increased the activities of major antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX) of ginger leaf tissue and higher concentration inhibited the activities of four antioxidant enzymes. However, stem and leaf aqueous extract inhibited the activities of four antioxidant enzymes with increase in concentration. Meanwhile, enhanced concentration of ginger aqueous extracts significantly reduced photo-parameters of ginger seedling (including CO2 concentration, stoma conductivity, net photosynthesis rate and transpiration rate). 3. Rhizome, stem and leaf ginger aqueous extract showed different effect on six soil enzyme activities, and acid phosphatase and invertase showed significant effect when aqueous extract concentration got 10 g l-1. Furthermore, six soil enzyme activities increased with increase in aqueous extract concentration. Bcterial and fungi number tended to increase while antinomyces tented to decrease with the increase in aqueous extract concentration of identical part. Ginger aqueous extracts reduced soil organic matter content with increased concentration, accompanying with NO3-—N accumulation in soil. Rhizome aqueous extract showed the same tendency for available P, available K and NH4+—N, namely lower concentration increased their contents in soil and higher concentration reduced their contents. While stem and leaf aqueous extracts reduced their contents with the increamental concentration. 4. All intercropping systems increased soil enzyme activities to different extent both at VGS and at HS compared to solo ginger. All intercropping systems increased the colony numbers of soil bacteria and total of soil microbe but not significantly either at VGS or at HS. All intercropping systems increased the colony numbers of soil fungi and actinomytes to a different extent (increase or decrease) both at VGS and at HS. For DI, difference between all cultivation patterns and S-G was not significant either at VGS or at HS except that G-S-C-G whose value was only 33.18% of S-G at VGS significantly decreased. G-S not only increased ginger yield by 19.6% but also obtained better economic benefit. Furthermore, all intercropping systems significantly inhibited occurrence of bacterial wilt of ginger. 5. Different cultivated pattern influenced plant height, tiller numbers, rhizome yields and intrinsic quality of ginger. Treatment 2 significantly facilitated tiller occurring (10.5%). Treatment 2, 3 and 4 promoted ginger growth (plant height respectively increased 15.0%、11.4% and 14.0%) and enhanced rhizome yields. Treatment 2 and 3 effectively increased vitamin C content (significantly increased 3.29% and 4.05% compared to solo ginger). Treatment 3 significantly increased contents of beneficial substances such as soluble sugar (8.2%), gingerols (4.6%) and protein. Treatment 2 significantly decreased contents of deleterious substance namely nitrate (14.0%) and improved appearance and intrinsic quality of ginger rhizome. Furthermore, treatment 2 (ginger/soybean intercropping) could obtain better economic benefit and showed the highest net income and ratio of benefit and cost whose values respectively increased by 24.80% and 8.8% compared to solo ginger.

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.

中国青藏高原青稞抗穗发芽资源评价与α-淀粉酶基因的克隆及表达

穗发芽（PHS，preharvest sprouting）是影响禾本科作物生产的重要的灾害之一。收获时期如遇潮湿天气容易导致穗发芽发生。发生穗发芽的种子内部水解酶（主要是α-淀粉酶）活性急剧升高，胚乳贮藏物质开始降解，造成作物产量和品质严重降低。因此，选育低穗发芽风险的品种是当前作物育种工作中面临的重要任务。 青稞(Hordeum vulgare ssp. vulgare)主要分布于青藏高原，自古以来就是青藏高原人民的主要粮食。近年来，由于青稞丰富的营养成分和特有的保健品质、在燃料工业中的潜力以及在啤酒酿造工业中的利用前景，在发达国家日趋受到重视，掀起综合研究利用的热潮。我国拥有占全世界2/3 以上的青稞资源，具有发展青稞产业的得天独厚的条件。然而，由于青稞收获期间恰逢青藏高原雨季来临，常有穗发芽灾害发生，使青稞生产损失巨大。目前对青稞穗发芽研究很少，适用于育种的穗发芽抗性材料相对缺乏，不能很好的满足青稞穗发芽抗性育种的需要。本研究以青藏高原青稞为材料，对其穗发芽抗性的评价指标和体系进行构建，同时筛选青稞抗穗发芽品种并对其抗性进行评价，还利用分子生物学手段对青稞穗发芽抗性的分子机理进行了初步探讨。主要研究结果如下： 1. 本试验以来自于我国青藏高原地区的青稞为材料，对休眠性测定的温度范围进行探讨，并对各种穗发芽抗性测定方法的对青稞的适用性进行评测。通过探讨温度对13 个不同基因型的青稞籽粒发芽和休眠性表达的影响，对筛选青稞抗穗发芽资源的温度条件进行探索，并初步分析了其休眠性表达的机理。在10，15，20，25，30℃的黑暗条件下，选用新收获的13 个青稞品种为材料进行籽粒发芽实验，以发芽指数（GI）评价其休眠性。结果发现，不同品种对温度敏感性不同，其中温度不敏感品种，在各温度条件下均表现很低的休眠性；而温度敏感品种，其休眠性表达受低温抑制，受高温诱导。15℃至25℃是进行青稞休眠性鉴定的较适宜的温度范围。通过对供试材料发芽后的α-淀粉酶活性，发现温度对青稞种子的休眠性表达的影响至少在一定程度上表现在对α-淀粉酶活性的调控上。随后，对分别在马尔康和成都进行种植的34 份青稞穗发芽指数（SI），穗发芽率（SR），籽粒发芽指数（GI）和α-淀粉酶活性（AA）进行了测定和分析，发现它们均受基因型×栽培地点的极显著影响，且四个参数之间具有一定相关性。GI 参数由于其变异系数较低，在不同栽培地点稳定性好，且操作简便，是较可靠和理想的穗发芽评价参数。SI 参数可作为辅助，区别籽粒休眠性相似的材料（基因型）或全面评价材料（基因型）的穗发芽抗性特征。AA 参数稳定性较差，并且检测方法复杂，因此不建议在育种及大量材料筛选和评价时使用。此外，青稞穗发芽抗性受环境影响较大，评价时应考虑到尽可能多的抗性影响因素及其在不同栽培条件下的变异。 2. 对来自青藏高原的青稞穗发芽抗性特征及其与其它农艺性状间的关系进行研究。通过测定穗发芽指数（SI）、籽粒发芽指数（GI）和α-淀粉酶活性（AA），表明113 份青稞材料的穗发芽抗性具有显著差异。SI、GI 和AA 参数的变幅分别为1.00~8.86、0.01~0.97 和0.00~2.76，其均值分别为4.72、0.63 和1.22。根据SI 参数，六个基因型，包括‘XQ9-5’，‘XQ33-9’，‘XQ37-5’，‘XQ42-9’，‘XQ45-7’和‘JCL’被鉴定为抗性品种。综合SI、GI 和AA 参数，可以发现青稞的穗发芽抗性机制包含颖壳等穗部结构的抗性和种子自身的抗性（即种子休眠性），且供试材料中未发现较强的胚休眠品种，除‘XQ45-7’外，所有品种在发芽第四天均能检测出α-淀粉酶活性。穗部结构和种子休眠的抗性机制因基因型不同而不同，在穗发芽抗性中可单独作用或共同作用。农家品种和西藏群体分别比栽培品种和四川群体的穗发芽抗性强，而在不同籽粒颜色的青稞中未发现明显差异。相关性检验发现，青稞的穗发芽抗性，主要是种子休眠性，与百粒重、开花期、成熟期、穗长、芒长和剑叶长呈显著负相关关系，与株高相关性不显著。农艺性状可以作为穗发芽抗性材料选育中的辅助指标。本试验为青稞穗发芽抗性育种研究提供了必要的理论基础和可供使用的亲本材料。 3. α-淀粉酶是由多基因家族编码的蛋白质，在植物种子萌发时高度表达，与植物种子的萌发能力密切相关。在大麦种子发芽时，高等电点α-淀粉酶的活性远大于低等电点的α-淀粉酶。为了研究不同穗发芽抗性青稞品种中编码高等电点α-淀粉酶Amy1 基因结构与抗性间的关系，我们以筛选得到的抗性品种‘XQ32-5’（TR1）、‘XQ37-5’（TR2）、‘XQ45-7’（TR3），易感品种‘97-15’（TS1）、‘9657’（TS2）以及强休眠大麦品种‘SAMSON’（SAM）为材料，对其Amy1 基因的编码区序列进行克隆和结构分析，并对它们推导的氨基酸序列进行比较。结果显示，青稞Amy1 基因具有三个外显子、两个内含子，编码区中有13 个核苷酸变异位点，均位于2、3 号外显子，2 个变异位点位于2 号外显子。SAM 和TS1 分别在2 号外显子相应位置有5 个相同的碱基(GAACT)的插入片段。相应α-淀粉酶氨基酸序列推导发现，所有核苷酸变异中有8 个导致相应氨基酸残基的改变，其余位点为同义突变。青稞Amy1 基因编码区序列品种间相似度高达99%以上，部分序列变异可能与其穗发芽抗性有关。随后，我们又通过SYBR Green 荧光定量技术对该基因在不同发芽时间（1d~7d）的相对表达水平进行了差异性检测。结果发现，7 天内不能检测到SAM 的Amy1 基因表达，5 个青稞品种间的Amy1 基因的相对表达量均随着发芽时间延长而上升，但上升方式有所不同。弱抗品种该基因表达更早，转录本增加速率更大，且在4~5 天可达到平台期。发芽7 天中，抗性品种总转录水平明显低于易感品种。本研究结果表明，青稞Amy1 基因的转录水平是与其穗发芽抗性高度相关。 我国青藏高原青稞，尤其是农家品种的穗发芽抗性具有丰富的变异，蕴藏着穗发芽抗性育种的宝贵资源。本研究为青稞穗发芽抗性育种建立了合理抗性评价体系，筛选出可供育种使用的特殊材料，阐明了农艺性状可辅助穗发芽抗性育种，同时还对穗发芽抗性与α-淀粉酶基因的结构和表达关系进行分析，为青稞穗发芽抗性资源筛选奠定了基础。 Preharvest sprouting (PHS) is a serious problem in crop production. It often takes place when encountering damp, cold conditions at harvest time and results in the decrease of grain quality and great loss of yield by triggering the synthesis of endosperm degrading enzymes (mostly the α-amylase). Therefore, PHS is regarded as an important criterion for crop breeding. In order to minimize the risk of PHS, resistant genotypes are highly required. Hulless barley (Hordeum vulgare ssp. vulgare) is the staple food crop in Qinghai-Tibetan Plateau from of old, where is one of the origin and genetic diversity centers of hulless barley. Recently, interest in hulless barley has been sparked throughout the world due to the demonstrations of its great potential in health food industry and fuel alcohol production. Indeed, hulless barley can also be utilized to produce good quality malt if the appropriate malting conditions are used. In China, overcast and rainy conditions often occur at maturity of hulless barley and cause an adverse on its production and application. PHS resistant genotypes, therefore, are highly required for the hulless barley breeding programs. However, few investigations have been made so far on this issue. The objectives of this study were: 1) to assessment of methods used in testing preharvest sprouting resistance in hulless barley; 2) to evaluate the variability and characteristics of PHS resistance of hulless barley from Qinghai-Tibet Plateau in China; 3) to select potential parents for PHS resistance breeding; 4) to primarily study on the molecular mechanism of PHS resistance of hulless barley. Our results are as followed: 1. We investigated the temperature effects on seed germination and seed dormancy expression of hulless barley, discussed appropriate temperature range for screening of PHS resistant varieties, and analyzed the mechanism of seed dormancy expression of hulless barley. The dormancy level of 13 hulless barley were evaluated by GI (germination index) values calculating by seed germination tests at temperature of 10，15，20，25，30℃ in darkness. There were great differences in temperature sensitivity among these accessions. The insensitive accessions showed low dormancy at any temperature while the dormancy expression of sensitive accessions could be restrained by low temperature and induced by high temperature. The temperature range of 15℃ to 25℃ was workable for estimating of dormancy level of hulless barley according to our data. Analysis of α-amylase activity showed that the temperature effects on seed germination and the expression of seed dormancy be achieved probable via regulating of α-amylase activity. Furthermore, we evaluated the differences in sprouting index (SI), sprouting rate (SR), germination index (GI) and α-amylase activity (AA) between Maerkang and Chengdu among 34 accessions of hulless barley from Qinghai-Tibetan Plateau in China. These PHS sprouting parameters were significantly affected by accession×location, and they had correlation between each other. GI was the most reliable parameter because of its low CV value, good repeatability and simple operation. SI could assist in differentiating between accessions of similar dormancy or overall evaluation of the resistance. AA was bad in repeatability and had relatively complex testing method, therefore, not appropriate for breeding and evaluation and screening of PHS resistant materials. Besides, since PHS resistance of hulless barley was greatly influenced by its growth environment, possibly much influencing factors and variations between cultivated conditions should be considered. 2. In this study, large variation was found among 113 genotypes of hulless barley (Hordeum vulgare ssp.vulgare) from Qinghai-Tibetan Plateau in China, based on the sprouting index (SI), germination index (GI) and α-amylase activity (AA) which derived from sprouting test of intact spikes, germination test of threshed seeds and determination of α-amylase activity, respectively. The range of SI, GI and AA was 1.00~8.86, 0.01~0.97 and 0.00~2.76，the mean was 4.72, 0.63 and 1.22 espectively. Six resistant genotypes, including ‘XQ9-5’, ‘XQ33-9’, ‘XQ37-5’, ‘XQ42-9’, ‘XQ45-7’ and ‘JCL’, were identified based on SI. Integrating the three parameters, it was clear that both hulls and seeds involved in PHS resistance in intact spikes of hulless barley and there was no long-existent embryo dormancy found among the test genotypes. All the genotypes, except ‘XQ45-7’, had detectable α-amylase activity on the 4th day after germination. There was PHS resistance imposed by the hull and seed per se and the two factors can act together or independent of each other. Besides, landraces or Tibet hulless barley had a wider variation and relatively more PHS resistance when compared with cultivars or Sichuan hulless barley. No significant difference was found among hulless barley of different seed colors. The correlation analysis showed PHS resistance was negatively related to hundred grain weight, days to flowering, days to maturity, spike length, awn length and flag length but not related to plant height. This study provides essential information and several donor parents for breeding of resistance to PHS. 3. Alpha-amylase isozymes are encoded by a family of multigenes. They highly express in germinating seeds and is closely related to seed germination ability. In barley germinating seeds, the activity of high pI α-amylase is much higher than low pI α-amylase. The aim of this study was to determine the relationship between preharvest sprouting resistance of hulless barley and the gene structure of Amy1 gene which encodes high pI α-amylase. The coding region and cDNA of Amy1 gene of three resistant accessions, including ‘XQ32-5’ (TR1), ‘XQ37-5’ (TR2), ‘XQ45-7’ (TR3), two susceptible accessions ‘97-15’ (TS1), ‘9657’ (TS2) and one highly dormant barley accession ‘SAMSON’ (SAM) was cloned. Analysis of their DNA sequences revealed there were three exons and two introns in Amy1 gene. Thirteen variable sites were in exon2 and exon3, 2 variable sites were in intron2. SAM and TS1 had a GAACT insert segment in the same site in intron2. Only 8 variable sites caused the change of amino acid residues. There were 99% of similarity between the tested hulless barley and some of the variable sites might be related with preharvest sprouting resistance. Then, we investigated the expression level of Amy1 gene in the 7-day germination test. Results of quantitative real-time PCR indicated that the relative expression trends of Amy1 gene were the same but had significant differences in the increase fashion between hulless barleys and no detectable expression was found in SAM. Susceptible accessions had earlier expression and faster increase and reached the maximum on day 4 ~ day 5. Besides, total transcripts level was found lower in resistant accessions than susceptible accessions. This study indicated that α-amylase activity was highly related to the transcription level of Amy1 gene which not correlated to missense mutation sites. In conclusion, hulless barley, especially the landraces from Qinghai-Tibetan Plateau in China possesses high degree of variation in PHS performance, which indicates the potential of Tibetan hulless barley as a good source for breeding of resistance to PHS. This study provides several donor parents for breeding of resistance to PHS. Our results also demonstrate that agronomic traits may be used as assistants for PHS resistance selection in hulless barley. Besides, analysis of high pI α-amylase coding gene Amy1 revealed the relative high expression of was Amy1 one of the mainly reason of different PHS resistance level in hulless barley.

Dependence of isoscaling parameters on nucleon-nucleon cross section and momentum-dependent interaction

Influences of the isospin dependence of the in-medium nucleon-nucleon cross section and the momentum-dependant interaction (MDI) on the isotope scaling are investigated by using the isospin-dependent quantum molecular dynamics model (IQMD). The results show that both the isospin dependence of the in-medium nucleon-nucleon cross section and the momentum-dependent interaction affect the isoscaling parameters appreciably and independently. The influence caused by the isospin dependence of two-body collision is relatively larger than that from the MDI in the mean field. Aiming at exploring the implication of isoscaling behaviour, which the statistical equilibrium in the reaction is reached, the statistical properties in the mass distribution and the kinetic energy distribution of the fragments simulated by IQMD are presented.