Reversible accumulation of (1→3,1→4)‐β‐glucan endohydrolase in wheat leaves under sugar depletion

A (1→3,1→4)‐β‐D‐glucan endohydrolase [(1→3,1→4)‐β‐glucanase, EC 3.2.1.73] was detected in wheat (Triticum aestivum L.) leaves by Western analyses and activity measurements. This enzyme is able to degrade the (1→3,1→4)‐β‐glucans present in the cell walls of cereals and other grass species. In wheat, enzyme levels clearly increased during leaf development, reaching maximum values at full expansion and then decreasing upon leaf ageing. To test whether the abundance of (1→3,1→4)‐β‐glucanase might be controlled by the carbohydrate status, environmental and nutritional conditions capable of altering the leaf soluble sugar contents were used. Both the activity and enzyme protein levels rapidly and markedly increased when mature leaves were depleted of sugars (e.g. during extended dark periods), whereas elevated carbohydrate contents (e.g. following continuous illumination, glucose supply in the dark or nitrogen deficiency during a light/dark cycle) caused a rapid decrease in (1→3,1→4)‐β‐glucanase abundance or prevented its accumulation in the leaves. The physiological significance of (1→3,1→4)‐β‐glucanase accumulation under sugar depletion remains to be elucidated.

Content of zinc, iron and their absorption inhibitors in Nicaraguan common beans (Phaseolus vulgaris L.).

Protein-energy malnutrition and mineral deficiencies are two of the three forms of nutritional deficiencies that affect most developing countries due to inadequate access to food and diets based on a sole crop. Common bean (Phaseolus vulgaris L.) is the staple crop of Nicaragua and it has the potential to improve the nutritional status of the poorest group of the nation. Its high content of both protein and nonhaem iron provides many nutrients, but inhibitors also may prevent absorption of iron and zinc by the human consumer. A proper production chain must be followed to ensure the best grain quality for the consumer. To achieve food security, both production and high nutritional content must be maintained. Four nationally important accessions of common bean, with different harvesting dates, were selected to be submitted to two treatments: to evaluate the impact of storage conditions on the end quality of the grain. The duration of the study was six months with sampling every six weeks, and the two treatments were controlled one stored at 40°C and 75 RH %, and the other was stored in in-situ conditions. Proximate and mineral composition was evaluated as well as tannin, phytate and bioavailability. Significant differences among different accessions were found, being the most significant in protein, Fe and Zn content, tannins and phytate. Protein values ranged from 21-23%. Iron content was 61-81 mg/kg but only 3-4% was bioavailable. Zinc content was 21-25 mg/kg and 10-12% was bioavailable. The concentration of phytate ranged from 8.6-9.6 mg/g while tannin values ranged within 37.7-43.8 mg/g. Storage at high temperatures was demonstrated to have an impact on certain nutritional compounds and proved detrimental to final grain quality. Soluble sugar content and tannin content decreased after six months in both storage conditions, IDF decreased in the in-situ and SDF in the stress. The iron content and bioavailability in INTA Biofortificado were not as outstanding as expected, so experiments should be conducted to compare its iron uptake and delivery with other cultivars.

不同葡萄糖/果糖类型桃果实发育期间可溶性糖的变化规律和代谢

以成熟果实中不同葡萄糖/果糖（G/F）类型的6个桃品种（G/F≈1品种：‘冈山白’、‘山一白桃’和‘燕红’;高G/F品种：‘张黄7号’、‘龙246’和‘临白7号’）为试材，采用高效液相色谱法测定果实发育期果实和叶片中可溶性糖含量，并在盛花后74 d或101 d测定了‘冈山白’、‘山一白桃’、‘张黄 7号’和‘龙 246’新梢韧皮部中可溶性糖的含量;测定了果实发育过程中‘山一白桃’和‘临白7号’果实中的可溶性糖和淀粉代谢相关酶的活性。研究成熟果实中不同G/F类型桃果实内G/F差异的部位和时期;分析桃果实内G/F差异的可溶性糖代谢调控机理。 成熟果实中不同G/F类型桃果实中均以蔗糖作为主要碳水化合物积累形式，花后43–85 d蔗糖含量很低，随后持续快速积累直至果实成熟;花后43–85 d山梨醇有升高趋势，在果实成熟前40 d左右迅速降低;葡萄糖和果糖含量在果实发育早期较高，之后逐渐降低;但两类不同G/F桃在整个果实发育过程中G/F值与果实成熟时相似。叶片中贮藏的可溶性糖主要是蔗糖和山梨醇，在果实整个发育期间，G/F≈1品种叶片中G/F约1-3，而高G/F品种叶片中G/F约为2-7。G/F≈1品种‘冈山白’和‘山一白桃’与高G/F品种‘张黄 7号’和‘龙 246’韧皮部中山梨醇占总可溶性糖47-63％，显著高于蔗糖、葡萄糖和果糖的含量，G/F为0.8-0.91，且两类不同G/F桃品种间G/F值不存在显著差异。 成熟果实中G/F≈1类型的‘山一白桃’和高G/F值类型的‘临白7号’整个果实发育过程中，葡萄糖、山梨醇和淀粉的含量在这两个品种间一般没有明显差异;‘山一白桃’果实中的果糖含量显著高于‘临白7号’果实中的果糖;果实最后迅速生长期，‘山一白桃’果实中的蔗糖明显高于‘临白7号’。‘山一白桃’和‘临白7号’果实中的NAD+依赖型山梨醇脱氢酶（NAD+-SDH）活性低，两者有相似的变化趋势，一般无显著差异。‘临白7号’果实中的NADP+依赖型山梨醇脱氢酶（NADP+-SDH）和山梨醇氧化酶（SOX）活性一直高于‘山一白桃’，两者NADP+-SDH和SOX的活性分别在花后93-123 d和花后43-93 d有显著差异。‘临白7号’果实中的果糖激酶（FK）活性一般高于‘山一白桃’。花后43-93 d，‘临白7号’果实中的磷酸蔗糖合成酶（SPS）和蔗糖合成酶（SS）活性一般显著‘山一白桃’。果实最后迅速生长期，蔗糖快速积累，葡萄糖、果糖、山梨醇和淀粉含量迅速降低，同时伴随有SPS和SS活性的迅速升高。在整个果实发育过程中，两个品种果实中的淀粉酶活性较高，其果实中的淀粉含量和淀粉酶活性都有明显的下降趋势。 研究结果表明，整个果实发育过程中桃果实中均存在G/F≈1和高G/F现象，光合产物在韧皮部的运输对桃果实的G/F没有显著的影响，果实中G/F的差异主要由于果实内糖代谢差异所导致。‘临白7号’果实中山梨醇向果糖方向的转化能力与‘山一白桃’一般没有显著差异，由于不同时期较高的NADP+-SDH和SOX活性，使得山梨醇向葡萄糖方向的转化能力明显高于‘山一白桃’，同时，‘临白7号’果实中的FK活性一般高于‘山一白桃’，因此导致‘临白7号’果实中G/F高于‘山一白桃’。

Acute biochemical responses of a submersed macrophyte, Potamogeton crispus L., to high ammonium in an aquarium experiment

Acute biochemical responses of Potamogeton crispus L. to high external ammonium were investigated in an aquarium experiment. Shoots of P. crispus were incubated in aquaria for 24 h or 48 h at five treatments of ammonium-0, 1, 5, 10 and 20 mg/L NH4-N. Soluble sugar content of the shoots declined markedly with increasing ammonium levels, whereas soluble amino acid content increased dramatically. Responses of two antioxidant enzymes as well as soluble protein content fit a lognormal distribution with increasing ammonium levels. High ammonium levels (NH4-N greater than or equal to 5 mg/L) caused significant acute biochemical changes in P. crispus, which potentially could lead to significant biochemical damage.

Salt tolerance of Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crust, was enhanced by exogenous carbohydrates

Microcoleus vaginatus isolated from a desert algal crust of Shapotou was cultured in BG-11 medium containing 0.2mol l(-1) NaCl or 0.2mol l(-1) NaCl plus 100mg l(-1) sucrose, extracellular polymeric substances (EPS) or hot water-soluble polysaccharides (HWP), respectively. Photosynthetic oxygen evolution rates, photosystem 11 activity (Fv/Fm) and dark respiration of NaCl-stressed cells were enhanced significantly by the added sucrose or EPS under salt stress conditions (0.2mol l(-1) NaCl). Compared with cells treated with salt alone, sodium contents in cells reduced significantly; the content of cellular total carbohydrate did not change, and intracellular sucrose, water-soluble sugar increased significantly following the addition of exogenous carbohydrates. Sucrose synthase (SS) activity of NaCl-stressed cells increased following the addition of sucrose, and sucrose phosphate synthase (SPS) activity of NaCl-stressed cells increased following the addition of exogenous sucrose, EPS or HWP compared with cells stressed with NaCl only. The results suggested that the extruded EPS might be re-absorbed by cells of M. vaginatus as carbon source, they could increase salt tolerance of M. vaginatus through the changes of carbohydrate metabolism and the selective uptake of sodium ions. (C) 2003 Elsevier Science Ltd. All rights reserved.

大气NH_3升高对不同供氮水平下小麦叶片光合生理特征的影响

以小麦品种‘小偃6号’(氮高效品种)和‘长旱58’(氮低效品种)为材料,采用开顶式气室和土培实验研究了大气NH3浓度升高对生长于高、低两种供氮介质下小麦植株不同生育期叶片净光合速率(Pn)、气孔导度(Gs)、叶绿素含量、叶绿素荧光参数(Fv/Fm、Fv/F0)和可溶性糖含量的影响。结果显示:两小麦品种高氨低氮处理植株的Pn、Fv/F0和可溶性糖含量均高于高氨高氮和低氨低氮处理,并在生育后期差异达显著水平(P<0.05),氮低效品种的Gs也符合上述规律且不同处理间差异显著(P<0.05);小麦各生育期高氨高氮处理下植株的Pn均显著低于低氨高氮处理,且两处理间灌浆期的叶绿素含量和灌浆期以前的可溶性糖含量的差异显著(P<0.05),而两处理灌浆期以前的叶绿素荧光参数Fv/Fm在各处理条件下均无显著差异;不同处理间及品种间各项光合特征指标差异缺乏规律性。可见,大气中NH3浓度升高有利于改善低供氮介质条件下小麦植株的氮营养状况,但不同氮效率品种间的响应存在差异。

不同前茬对设施黄瓜产量和品质及土壤酶活性的影响

试验研究了在延安日光温室不同前茬作物条件下,黄瓜随着生长季节的变化其产量和品质及土壤呼吸和酶活性的动态变化。结果表明,前茬为豇豆的黄瓜产量和土壤碱性磷酸酶活性较高,前茬为番茄的黄瓜可溶性糖含量和土壤呼吸强度较高,前茬为四季豆的黄瓜维生素C含量较高,前茬为翻青玉米的黄瓜硝酸盐含量和土壤脲酶活性较高,前茬为翻青黑豆的土壤蔗糖酶活性较高。从提高黄瓜产量的角度出发,豇豆-黄瓜是最佳模式,而从改善黄瓜品质的角度出发,番茄-黄瓜和四季豆-黄瓜是最优模式

黄土高原南瓜高糖低硝酸盐施肥模式研究

采用N、P、K3因素最优设计,在陕北黄土高原进行了南瓜氮、磷、钾用量及其肥效反应模式田间试验,研究不同施肥量对南瓜硝态氮、可溶性糖两项营养品质的影响,旨在探讨南瓜品质高糖低硝酸盐的N、P、K肥效反应模式,提出优化的施肥方案。结果表明,N肥单因素对南瓜硝态氮和可溶性糖含量影响最大,K肥单因素对南瓜硝态氮和可溶性糖含量影响不显著,N与P交互作用对南瓜高糖低硝酸盐影响显著,K肥施用量一定时,氮肥与磷肥的施用量不易过大。根据南瓜N、P、K肥效反应模式,筛选出南瓜品质硝态氮含量在200mg·kg-1以下、可溶性糖含量在7%以上的较佳施肥量为施氮95～120 kg·hm-2,施磷40～70 kg·hm-2,施钾35～80 kg·hm-2,N∶P2O5∶K2O=1∶0.42∶0.37。

花椒水浸液及酚酸类化感物质对作物种子萌发和幼苗生长的影响效应

花椒（Zanthoxylum piperitum）是川西干旱河谷地区的重要经济作物，化感作用是花椒连作障碍的原因之一。系统研究花椒化感作用有助于深入理解并最终解决花椒连作障碍。本文通过研究花椒叶、林下土壤浸提液及单一纯化感物质对花椒幼苗生长、苜蓿种子萌发及幼苗生长的影响作用，从生理生化角度揭示浸提液及纯化感物质的作用方式。通过室外和室内模拟实验，对浸提液及纯化感物质的化感效应进行比较，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。主要结果如下： 1.花椒叶及林下土壤浸提液对地下生物量影响作用强与对地上生物量的化感效应，两种浸提液的化感效应强度不同，叶浸提液作用表现更显著。其中在Y6、Y8 、T6和T8处理时，花椒幼苗地下生物量分别降低了31.2%、32.1%、31.6%和31.7%。 2.两种浸提液均能显著影响花椒幼苗体内的保护性酶活性，总体说来，在高浓度下抑制各种抗氧化物酶活性，幼苗体内丙二醛含量增加，幼苗受害严重；在较低浓度下，各种保护性酶活性有所增加，丙二醛含量减少，幼苗伤害减轻。同时，不同月份里，各种酶的活性高低显著不同，9月份的活性显著低于7月份的酶活性。对于养分含量的影响，Y8、T8的影响强度最大，分别使碳元素含量降低了27.8%和30.8%，使钾元素含量降低了34.7%和25.6%。 3.花椒叶及林下土壤浸提液对苜蓿种子萌发及幼苗生长有化感作用，表现在最终萌发率、不同物质代谢及保护性酶活性的差异上。两种浸提液对苜蓿种子萌发过程中蛋白质的含量均无显著性影响，对淀粉和可溶性糖的影响作用类似，高浓度处理无明显化感效应，较低浓度处理显著降低二者在萌发苜蓿种子中的含量。Y2、Y4与T4处理分别使可溶性糖含量减少了32.3%、29.1%和18.8%，Y2与T2处理分别使淀粉含量降低了29.3%和26.8%。 4.苜蓿种子在4种单一化感物质最高浓度即10-3 mol•L-1处理下，萌发率显著降低，半数萌发时间推迟，随着处理浓度降低，抑制作用逐渐减弱，当降低到10-6 mol•L-1时，又能够表现出对苜蓿种子萌发的促进作用。 5.纯化感物质在10-6 mol•L-1时使苜蓿幼苗叶片的保护性酶活性显著升高，丙二醛含量显著降低；在10-3 mol•L-1时使苜蓿叶片中保护性酶活性显著降低，丙二醛含量增加，膜脂过氧化程度加重。 Zanthoxylum piperitum is one of the most important cash crops and has been extensively cultivated in Eastern Tibetan Plateau, especially in the fragile dry valley areas. Allelopathic effects could be a reason for Z. piperitum’s continuous cropping impediment. Systemmatically research of the effect of Z. piperitum allelopathy could help to comprehend the continuous cropping impediment. The allelopathic effects on seedlings growth and seed germination of aqueous extracts of Zanthoxylum piperitum and phenolic allelochemicals were studied, and the action mechanism of the two substances was also discussed from physiology. Indoor and outdoor experiments were set to compare the difference between aqueous extracts and pure allelochemicals. The main results showed that: 1. The aqueous extracts of leaf and soil had significant allelopathic effects on aboveground and underground biomass, but the effect on underground biomass was stronger than the effect on underground evidently. Treated with Y6、Y8 、T6 and T8, the underground biomass was reduced 31.2%、32.1%、31.6% and 31.7% respectively. 2. The activity of activities of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase were significantly reduced, while the content of MDA was increased and the seedlings were suffered stronger, when treated by the high concentration; but at the low concentration, these were reversed. And then, at the different month, the activities of antioxidant enzyme were significantly distinct. As for the contents of nutrient element, Y8、T8 had the more intensive effects than other treatments. 3. The results showed that the two types of aqueous extracts had significant allelopathic effects on seed germination, substances metabolize and the activity of antioxidant enzyme. But the aqueous extracts had no effects on the content of protein, while had the similar effects on the content of starch and soluble sugar. At Y2、Y4 and T4, the content of soluble sugar decreased 32.3%、29.1% and 18.8% respectively. 4. Treated with 10-3 mol•L-1 of the four allelochemicals, the seed germination of alfalfa was significantly inhibited. Ferulic acid, coumarin and vanillic acid at 10-3 mol•L-1 significantly reduced the activities of antioxidant enzyme, while the content of MDA in alfalfa seedling was significantly increased. The restrain effects became weakened with the treat concentration falled. However, ferulic acid, coumarin and vanillic acid could increase the activities of antioxidant enzyme at 10-6mol•L-1.

青杨组(Populus section Tacamahaca Spach)不同种对增强UV-B的反应差异

人类向大气中排放的大量氮氧化合物和氟氯烃类化合物(CFC’s)引起臭氧分子的分解，导致到达地球表面的紫外辐射增加，特别是UV-B辐射增强。本项目以青杨组杨树为模式植物，从形态和生理方面研究了来自不同UV-B背景下的康定杨与青杨在增强UV-B下的反应及其反应差异,并探讨了干旱、施肥对它们抗UV-B能力的影响。杨树具有分布广、适应性强、在生态环境治理和解决木材短缺方面均占有重要位置，研究成果可为生态系统的恢复与重建提供理论依据和科学指导。主要研究结果有以下： 1. 在温室中经过增强UV-B处理，杨树的外部形态及生理活动受到了一定程度的影响。增强UV-B导致康定杨、青杨的生物量、叶面积及节间长度降低，叶片增厚，SOD活性升高，膜伤害增加，而对叶片数目、R/S、叶绿素A、叶绿素B及整个叶绿素含量没有影响。两种杨树对UV-B胁迫的响应存在差异：在增强UV-B条件下，青杨的植株高度、生物量、叶面积、脯氨酸含量、长期用水效率受到的影响大于康定杨，相比而言，康定杨在比叶面积、叶片厚度、可溶性糖含量、UV-B吸收物质的含量及SOD和GPX活性方面增加的程度大于青杨。这些区别说明，来自于高海拔的康定杨比来自于低海拔的青杨对增强UV-B 具有更强的耐性。我们认为二者在叶片厚度、比叶面积、UV-B吸收物质含量及SOD、GPX活性差异是导致对增强UV-B耐性不同的原因。 2. 干旱与增强UV-B对杨树的生长和生理特性均产生了影响，而且两种胁迫共同作用时干旱表现减弱或加剧了UV-B对杨树某些形态和生理特性的影响。 据试验结果，干旱显著地降低了杨树的株高、叶片数目、叶面积，增加了叶片厚度，促进ABA的积累，提高了CAT活性。对于干旱，两种杨树之间也表现出了一定的差异性。可溶性蛋白质和脯氨酸在青杨叶片中得到显著积累，而在康定杨中没有变化。此外，CAT、长期用水效率在康定杨中受到的影响更加明显。长期用水效率的不同变化趋势说明两种杨树对水分胁迫采用了不同的用水策略，康定杨采用的是节水用水策略，提高用水效率，而青杨采用的是耗水的用水策略。根据干旱对叶面积、脯氨酸、ABA含量、CAT活性及长期用水效率等方面的影响，我们认为来自高海拔地区的康定杨比来自低海拔的青杨有更大的耐旱性，这是对生长环境长期适应的结果。在高海拔地区，因霜冻常带来土壤水分不可利用，降低了根系对水分的吸收，树木容易受到的生理性干旱。另外，高海拔的地区低的气温使植株对严寒有较强的耐性，减少了水分的需要。 生长于增强UV-B下的康定杨和青杨植株表现为高度降低，叶面积缩小，比叶面积增加；叶片栅栏组织、海绵组织均受到增强UV-B的影响，其厚度的增加导致整个叶片变厚。增强UV-B还显著提高了杨树的APX活性、UV-B吸收物质含量，而对叶片数目、ABA、可溶性蛋白质含量及CAT活性没有产生影响。试验中也观察到了两种杨树对增强UV-B响应的差异：与康定杨相比，在增强UV-B下青杨株高、叶面积降低的程度更大一些，SOD活性显著提高。另外UV-B吸收物质受到的影响不同。根据这些差别，高海拔的康定杨(3500 m)比来自低海拔的青杨(1500 m)增强UV-B有较强的耐性。 与水分充足情况下UV-B对植株的影响相比，干旱对杨树抗增强UV-B产生了一定的影响，表现为加剧或减弱UV-B对植物的影响，但这种影响与形态、生理指标有关。当干旱与增强UV-B共同作用时，杨树植株的株高、叶面积进一步降低、叶片进一步增厚。就脯氨酸的积累的而言，在没有水分胁迫时，增强UV-B促使它显著增加，而在干旱处理下这种效果变得不明显。干旱对增强UV-B的影响还与杨树的种类有一定的关系。在康定杨中，干旱减弱了增强UV-B对栅栏组织与海绵组织的影响，且在植株高度、叶面积上表现出累加效应，而在CAT上交互作用显著；但在青杨中干旱则加剧增强UV-B对栅栏组织与海绵组织的影响，在植株高度、叶面积及比叶面积上表现出显著的交互作用。据碳同素分析，在水分充足的条件下，无论是康定杨，还是青杨，增强UV-B均导致其长期用水效率的提高，然而当两种胁迫共同作用时，长期用水效率则表现出差异，在青杨中，长期用水效率得到进一步增高，而康定杨中干旱的效应被增强UV-B所减轻。 3. 田间试验表明，杨树的生长、生理特征都受到养分和增强UV-B的影响。施肥对杨树的影响表现为：提高了叶面积、生物量及SOD的活性，降低了抗坏血酸含量。对于施肥作用，两种杨树的反应也有区别：在康定杨中施肥显著增加了的叶片长度、宽度及光合色素的含量，降低了净光合速率、气孔导度及胞间CO2浓度；在青杨中，则SOD、GPX、APX活性表现增加。从试验看出，施肥对来自于高海拔地区的康定杨(3500 m)的影响较大，对来自低海拔的青杨(1500 m)影响较小，这与它们对原产地的生境适应有一定关系。在康定杨生长的高海拔地区，低温度和湿度不能为地上凋落物或土壤中的根分解提供理想的条件，造成当地土壤的低养分状况，所以当肥料施用以后，效果显著。 经过增强UV-B处理，杨树叶片中UV-B吸收物质含量、GPX的活性得到提高，而脯氨酸、丙二醛、可溶性蛋白质、叶绿素及类胡萝卜素含量没有受到影响。对于增强UV-B两种杨树受到的影响也有所不同：在青杨中增强UV-B导致叶面积缩小，生物量、净光合速率降低，APX的活性及长期用水效率的提高，而对康定杨的这些指标没有产生显著影响，相反抗氧化酶的活性明显高于青杨。这些差异性是由于两种杨树对原产地不同UV-B背景的长期适应结果。康定杨长期生长在较高UV-B环境中，对UV-B有较强的耐性。而青杨适应于较低的UV-B环境，对增强UV-B较为敏感。 试验中施肥也影响了植株对增强UV-B的反应，不过这种影响与杨树的种类及测定指标有一定的相关性。例如，在缺肥的情况下，青杨的长期用水效率和康定杨的叶绿素含量都受到增强UV-B的显著影响，而施肥以后这种影响变得不显著。在缺肥的条件下，GPX、APX在青杨中的活性、GPX在康定杨中的活性对增加UV-B反应不敏感；而施肥以后则变化显著，同样胞间CO2浓度在康定杨也有类似的变化。 For past decades, Ultraviolet radiation, especially UV-B reaching the Earth’s surface increased because of depletion of ozone layer resulted from emission of NxO and CFC’s from human activities. In this experiment, different species of Populus section Tacamahaca Spach from different UV-B background were selected as a model plant to assess the effects of enhanced UV-B radiation. Morphological and physiological traits induced by enhanced UV-B were observed and the different responses between P. kangdingensis and P. cathayana were discussed, furthermore the influences of drought and fertilizer on responses induced by enhanced UV-B were studied. Since poplars play an important role in lumber supply, and are important component of ecosystems due to their fast growth and wide adaptation, the study could provide a strong theoretical evidence and scientific direction for the afforestation, and rehabilitation of ecosystem. The results are as follows: 1. The experiment conducted in a greenhouse indicated that morphological and physiological traits of two poplars were affected by enhanced UV-B radiation. Enhanced UV-B radiation not only reduced biomass, leave area and internode length, but also increased leaf thickness and SOD activity as well as MDA concentration and electrolyte rate. However, no significant changes in leaf numbers, root shoot ratio, and total chlorophyll and chlorophyll component were observed. There were different responses to enhanced UV-B radiation between two species. Compared with P. kangdingensis, cuttings of P. cathayana, exhibited lower height increment and smaller leaf area. In addition, there were significant differences in free proline, soluble protein, and UV-B absorbing compounds, and the activity of SOD and GPX, long-term WUE between them. Differences in plant height, biomass, leaf area, free proline concentration, and long-termed WUE showed that P. cathayana were more affected by enhanced UV-B radiation than P. kangdingensis. In contrast, more increase of specific leaf mass, leaf thickness, and soluble sugar, and UV-B absorbing compounds, and activity of SOD and GPX were observed in P. kangdingensis. According to these results, we suggested that P. kangdingensis from high elevation, which adapted to higher UV-B environments, had more tolerance to enhanced UV-B than P. cathayana from low elevation, which adapted to lower UV-B environment. We believe it was the difference of leaf thickness, specific leaf mass, and UV-B absorbing compounds as well as the activity of SOD and GPX resulted in lower adaptation of P. cathayana to enhanced UV-B radiation. 2. Growth and physiological traits of two poplars were affected by both drought and enhanced UV-B radiation. Moreover, it was observed that when two stresses applied together drought could exacerbate UV-B effects or decrease sensitivity to UV-B. In the experiment, drought significantly decreased plant height, leaf numbers, leaf area, and increased leaf thickness, and ABA, and CAT activity of two poplars. There were significant interspecific differences to drought stress. Exposed to drought, soluble protein and proline concentration were increased in P. cathayana but not in P. kangdingensis. However, more changes in CAT and long-term WUE were observed in kangdingensis. Different change in long-term WUE suggests that two poplars adapted different water-use strategies. P. kangdingensis employ a conservative water-use strategy, whereas P. cathayana employ a prodigal water-use strategy. Based on the differences in leaf area, accumulation of free proline and ABA, CAT activity as well as long-term WUE, we believed that P. kangdingensis from high elevation had a greater tolerance to drought than P. cathayana from low elevation，which is the result of adaptation to local environment. In high elevation area, trees are prone to suffer from physiological drought because of un-movable water caused by frost. Besides lower temperature enable the plants had greater adaptability to frost as a results the requirement of water is reduced Enhanced UV-B radiation decreased shoots height, leaf area, and increased specific leaf mass and thickness of palisade and sponge layer as well as APX activity and UV-B absorbing compounds in both species. Whereas, leaf numbers, ABA content, soluble protein and CAT activity showed no differences to enhanced UV-B radiation. Interspecific differences were also observed. Compared with P. kangdingensis, P. cathayana showed lower shoot height and smaller leaf area, higher SOD activity. Besides, variation in UV-B absorbing compounds was found. These differences suggested that P. kangdingensis from high elevation (3500 m) was more tolerant to enhanced UV-B radiation than P. cathayana from low elevation (1500 m). Compared with morphological and physiological changes induced by enhanced UV-B radiation under well-watered conditions, drought exacerbated or decreased these changes. However, these effects vary with parameters measured. When two stresses applied together, shoot height and leaf area further decreased while leaf thickness further increased. Under well-watered conditions, enhanced UV-B radiation significantly increased proline content, but such effect was not observed under drought conditions. The effect of drought on enhanced UV-B radiation was related to species. For example, drought reduced the effects of enhanced UV-B radiation on palisade parenchyma and sponge mesophyll in P. kangdingensis, and additive effects in shoot height and leaf area and interactive effect CAT activity were observed. In contrast, for P. cathayana drought significantly exacerbated the effects of enhanced UV-B radiation on palisade parenchyma and sponge mesophyll; there were noticeable interaction in shoot height, leaf area and specific leaf mass. As far as long-term WUE is concerned, it was increased by enhanced UV-B radiation under well-watered conditions in both species. While different effect was observed between two species in combination of two stresses. Long-term water use efficiency was further increased in P. cathayana whereas the effect was less significant in P. kangdingensis. 3. The field experiment showed that growth and physiological traits of poplars were affected by nutrition and enhanced UV-B radiation. Fertilization significantly increased leaf area, biomass and SOD activity, reduced Ascorbic acid concentration. There was interspecific difference in response to fertilization. For P. kangdingensis, fertilization significantly increased leaf width, leaf length and photosynthetic pigments content while net photosynthetic rate and stomatal conductance, intercellular CO2 concentration were significantly decreased. However, for P. cathayana, these parameters were unaffected except the increase of SOD, GPX and APX activity. From above, it could concluded that P. kangdingensis from high elevation was more affected by fertilization than P. cathayana, This difference was due to adaptation to local environment., The low temperature and moisture where P. kangdingensis was collected can not provided optimum to decompose roots and litter fall as a result the nutrition in soil was poor. Exposed to enhanced UV-B radiation, for both species UV-B absorbing compounds and GPX activity were significantly increased while proline, MDA, soluble protein, chlorophyll, carotenoids were not affected. Different responses were also observed between the two species. Enhanced UV-B radiation caused significant decreases in leaf area, biomass, net photosynthetic rate and increase in APX activity and long-term WUE in P. cathayana but not in P. kangdingensis. In addition, activity in antioxidant enzymes was much higher in P. kangdingensis than in P. cathayana. In the experiment fertilization affected responses of cuttings to enhanced UV-B radiation, but it concern species and parameters measured. Long-term WUE in P. cathayana and chlorophyll in P. kangdingensis were significantly increased by enhanced UV-B radiation under non-fertilization treatments while the increase was not found under fertilization treatment. In contrast, under no fertilization treatment enhanced UV-B radiation did not affected GPX and APX activity in P. cathayana and GPX in P. kangdingensis while significant increase appeared after application of fertilization. Similar effect of enhanced UV-B radiation on intercellular CO2 concentration in P. kangdingensis was observed.

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.

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.

青杨组(Populus Section Tacamahaca Spach)不同种对非生物胁迫的响应差异

土壤是人类赖以生存的自然环境和农业生产的重要资源，目前土壤受到干旱和盐胁迫的危害越来越严重。杨树具有适应性强、生长快和丰产等特性，本论文以青杨组杨树为模式植物，研究杨树对土壤干旱和盐胁迫的生态生理及蛋白质组学反应，研究成果可为我国干旱半干旱地区营造人工林、防止沙漠化提供理论依据，也为恢复与重建盐污染地区退化生态系统提供科学指导。主要研究结果如下： 1 青杨不同种对逐步干旱胁迫的响应差异 将来自喜马拉雅山东缘高海拔的康定杨和低海拔的青杨枝条扦插在温室中，用来检测它们对逐步干旱胁迫的响应。研究结果表明来自不同海拔的杨树对逐步干旱胁迫的适应性反应是不一样的。株高、叶片发育、叶片相对含水量、丙二醛、过氧化氢等指标的显著性变化在青杨中比在康定杨中来得早些，而且随着干旱胁迫程度的增加，这些参数的变化越来越明显，尤其是当青杨受到严重干旱胁迫的时候；而可溶性蛋白、可溶性糖、游离脯氨酸、抗氧化酶活力变化在康定杨中来得早一些。与青杨相比，在干旱胁迫下，康定杨仍能保持较好的植株生长和叶片发育；康定杨也能在逐步干旱条件下积累更多的可溶性蛋白、可溶性糖、游离脯氨酸及抗氧化酶活力，但是在丙二醛和过氧化氢含量方面增加的更少些。而且，我们的研究结果表明高海拔的康定杨有更强的耐干旱能力，杨树对干旱胁迫的适应能力与干旱发生的速度、强度、持续时间及两种杨树的海拔有关。 2 干旱胁迫下青杨不同种的蛋白质组学分析 来自青杨和康定杨雌株的枝条扦插在温室中，用来研究它们对干旱胁迫的蛋白质组学反应。采用TCA-丙酮/酚提取法提取总蛋白，并进行双向电泳分析。在每个处理的重复图像中都能检测到1,000 个以上的蛋白点。在青杨中有58 个蛋白在干旱处理后发生显著变化，其中22 个蛋白通过肽指纹图谱成功鉴定。康定杨中有69 个蛋白的表达量发生了显著变化，其中有25 个蛋白通过肽指纹图谱成功鉴定。这些被鉴定的蛋白主要参与了光合作用、氧化还原平衡、信号传导、能量代谢、蛋白质合成等过程。尽管被鉴定的蛋白只占叶片总蛋白的很少一部分，但这些被鉴定的干旱响应蛋白可能对维持植株内部平衡方面有重要作用。 3 青杨的盐胁迫响应 青杨植株分别用 0、50 和100 mM NaCl 溶液进行处理。叶片相对含水量、叶绿素a、b 含量、CO2 同化速率和气孔导度的降低表明叶绿体受到了盐胁迫的影响。过氧化氢、丙二醛含量及电导率的升高表明细胞受到了伤害。可溶性糖、游离脯氨酸含量及抗氧化酶含量的上升增加了植株耐盐胁迫的能力。在每个处理的重复图像中都能检测到1,000 个以上的蛋白点。其中有38 个盐响应蛋白被成功鉴定，有16 个蛋白(点4、10、11、14、15、21、24、26、27、28、33、34、35、36、37 和38)出现在盐胁迫的植株中；3 个蛋白(点10、11 和35)只出现在重度盐胁迫处理中；而1 个蛋白(点1)只出现在对照处理中。2 个蛋白(点1 和2)表达量下降，其余蛋白点表达量都增加。被鉴定的蛋白一部分参与了生理生化反应，而另一部分则在信号传导、蛋白质合成等方面有重要作用。盐胁迫下的生理生化变化及蛋白质组学的联合研究有利于青杨对盐胁迫的适应性分析。 Soil is the indispensable environment for human survival and important resource for agriculture development. Nowadays soil is threatened by drought stress and salt stress. Poplars (Populus spp.) possess some characters such as strong acclimilation, fast growth and great production of biomass. In this study, different species of Populus section Tacamahaca spach were used as model plants to investigate the ecophysiological and proteomic responses to drought stress and salt stress. Our results can provide theoretical evidence for the afforestation and prevention of desertification in the arid and semi-arid areas, and also can supply scientific direction for the reconstruction and rehalibitation of ecosystems contaminated by salinity. The results are as follows: 1 Adaptive responses to progressive drought stress in two contrasting poplar species originating from different altitudes Cuttings of Populus kangdingensis C. Wang et Tung and Populus cathayana Rehd., originating from high and low altitudes in the eastern Himalaya, respectively, were examined during one growing season in a greenhouse to determine the effects of progressive drought stress. The results manifested that the adaptive responses to progressive drought stress were different in these two species from different altitudes. Significant changes in height increment, leaf development, relative water content (RWC), malondialdehyde (MDA) and hydrogen peroxide (H2O2) appeared earlier in P. cathayana than in P. kangdingensis, whereas changes in soluble protein, soluble sugar, free proline and antioxidant enzymes appeared earlier in P. kangdingensis. In addition, changes in these parameters became more and more significant when the drought stress progressed, especially under severe drought stress in P. cathayana. Compared with P. cathayana, P. kangdingensis was able to maintain a superior height increase and leaf development under drought stress. Also, P. kangdingensis possessed greater increments in soluble protein, soluble sugar, free proline and antioxidant enzymes, but lower increments in MDA and H2O2 than did P. cathayana when the cuttings were exposed to progressive drought stress. Our results suggest that P. kangdingensis originating from the high altitude has a better drought tolerance than does P. cathayana originating from the low altitude. Furthermore, this study manifested that acclimation to drought stress are related the rapidity, severity, duration of the drought event and the altitude of two contrasting species. 2 Proteomic responses to drought stress in two contrasting poplar species originating from different altitudes The cuttings from a female clone of P. kangdingensis and P. cathayana were used to determine proteomic response to drought stress, respectively. Total proteins of the leaves were extracted by a combination of TCA-acetone and phenol, and separated by two-dimensional gel electrophoresis. More than 1,000 protein spots were reproducibly detected on each gel. 58 differentially expressed spots were detected under drought stress in P. cathayana and 22 drought-responsive proteins were identified by peptide mass fingerprint. 69 differentially expressed spots were detected under drought stress in P. kangdingensiss and 25 drought-responsive proteins were identified by peptide mass fingerprint. The identified proteins are involved in several processes, i.e., signal transduction, protein processing, redox homeostasis, CO2 fixation and energy metabolism. Although the proteins identified in this investigation represent only a very small part of the poplar leaf proteins, some of the novel drought-responsive proteins identified here may be involved in the establishment of homeostasis in response to drought stress in the woody plants. 3 Responses to salt stress in P. cathayana Cuttings from a female clone of P. cathayana were treated by Hoagland’s solution: 0, 50, 100 mM NaCl, respectively. Salinity significantly decreased the relative water content of leaves, the contents of chlorophyll a and chlorophyll b, CO2 assimilation rate (A) and stomatal conductance (gs) in both salt stress treatments，which suggested the chloroplast was affected by salt stress. The observed increases of H2O2 and malondialdehyde contents and electrolyte leakage suggested that salinity caused cellular damage, whereas the increases in compatible solutes and in the activities of antioxidant enzymes enhanced the salt tolerance. More than 1,000 protein spots were reproducibly detected on each gel, and 38 salt-responsive proteins were successfully identified by peptide mass fingerprint (PMF). 16 spots (spot 4, 10, 11, 14, 15, 21, 24, 26, 27, 28, 33, 34, 35, 36, 37 and 38) absent in the control sample were induced by the salt treatment, and three spots (spot 10，11 and 35) were present only in the severely salt-stressed treatment. The %vol of the differentially expressed proteins generally increased with progressing salt stress, except for the decreased %vol of two proteins (spot 1 and 2) under salt stress and the presence of spot 1 only in the control sample. Some of the novel salt-responsive proteins identified here may be involved in physiological, biochemical response to salt stress in P. cathayana, the other identified proteins play a role in numerous cellular functions, including signal transduction and protein processing. An integrated physiological, biochemical and proteomic approach was used here to systematically investigate salt acclimation in poplar.

容器苗质量评定指标的研究

In this paper,the assessing indices of container seedlings quality were synthesized in accordance with growth and physiological factors. The results showed that the seedling quality might be determined by the dormancy state of terminal bud,nutrient condition of plant,and the state of root system. The critical quality indices should include stem diameter at soil surface,dry weight of terminal bud,and soluble sugar content. Moreover,some indices such as root system vitality and dry weight of plant were also important.

Diversity and nutritional properties of Pakistani dates: implications for sustainable value chain and decent living perspectives of rural households

Date palm (Phoenix dactylifera L.) occupies almost three percent of the total worldwide cultivated area, with an annual production of seven million tonnes (t). Pakistan is an ideal place for the cultivation of date palm due to its sandy loam soil and semi-arid climate. In 2012, Pakistan produced 600,000 t of dates, on an area of 95,000 ha. Baluchistan province is the country’s top date producer, followed by Sindh, Punjab and Khyber Pakhtunkhwa (KPK) provinces. More than 300 date varieties are known to exist in Pakistan and some commercially important cultivars are: Karbalaen, Aseel, Muzawati, Fasli, Begum Jhangi, Hillawi, Dashtiari, Sabzo, Koharaba, Jaan Swore, Rabai and Dhakki. Six districts from the four provinces of Pakistan (Jhang, Muzaffargarh and Bahawalpur (Punjab), Dera Ismail Khan (KPK), Khairpur (Sindh) and Panjgur (Baluchistan)) with largest area under date palm cultivation were selected to conduct socio-economic surveys including the income sources of date palm growers. A structured questionnaire with open-ended and closed questions was used for face-to-face interviews of 170 date palm growers. At each location after selection of a first farmer through a local guide, the former was requested to provide names and addresses of three other date growers in his area. From these three names, one was randomly selected for the next sampling. Additionally, date palm fronds and fruits of all available cultivars were collected for morphological and nutritional analyses. Soil samples were collected from the groves for subsequent chemical and physical analyses. Almost all farmers used dates as a food item for their families and some were using low quality dates as a feed for their livestock. Apart from dates, other date palm components (trunk, spadix, frond, inflorescence and seed) were used by date palm growers as a raw material for making many by-products for their families. Date palm had a major contribution in the income of households, 24% received 91-100% of their income from date palms. More than half of the surveyed farmers had date palm groves, but scattered plantations, home gardens and intercropping systems with cereal and other fruits were also present. Dhakki, Muzawati, Aseel, and Karbalaen were the most important commercial cultivars grown in the provinces of KPK, Baluchistan, and Sindh. Aseel, Karoch, Haleni, Karbalaen, and Muzawati cultivars had the most firm fruit and good total soluble sugar, calcium and magnesium contents. The amount of magnesium found in dates of studied cultivars ranged from 0.143 to 0.876 mg g-1. A great variation in frond morphology was recorded among the cultivars. Fruit length and fruit weight was highest in Dhakki date, making it visually more attractive for customers in addition to its good nutritional properties. The seed weight of the studied cultivars ranged from 0.7-2.0 g, while Desi dates had largest seed, making them less attractive for marketing. However, in terms of nutritional value and fruit size, most of the investigated varieties can compete with globally important commercial dates.