花椒主效化感物质分离鉴定及化感作用研究

近年来，随着对作物重茬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。花椒（Zanthoxy piperitum.）为芸香科植物，是一种收益早、用途广、价值高的经济树种，是川西干旱河谷地区的重要经济作物，其连作障碍也倍受关注，系统研究花椒化感作用将有助于理解和最终解决花椒连作障碍问题。本文首先通过萃取、层析等方法分离花椒主效化感成分；通过外加不同浓度的花椒叶水浸液研究了对土壤氮素养分循环的影响；研究了花椒叶水浸液对苜蓿生理生化、光合作用、氮素养分吸收的影响，并对外施氮肥对这种化感影响的缓解作用做了研究；研究了花椒化感潜力对全球变化——UV-B增强辐射的响应。主要研究结果如下： 1．用不同极性的有机溶剂对花椒叶水浸液浓缩浸膏萃取、柱层析，结合生物活性检测，分离得到主效化感作用组分的一种化感物质——对甲氧基苯酚。采用该物质纯品进行生物活性检测，证明其具有化感作用。 2．花椒叶水浸液处理土壤30天后，土壤硝态氮、铵态氮、无机氮（硝态氮＋铵态氮）与对照相比，随着花椒叶水浸液浓度的增加呈现降低的趋势，其中土壤铵态氮含量显著降低，而硝态氮含量的变化则不显著，无机氮含量也显著降低。土壤脲酶和蛋白酶的活性与无机氮含量的变化趋势相同。随着花椒叶水浸液浓度的增加，氨化细菌数量显著降低，固氮菌的数量变化不显著，硝化细菌和反硝化细菌数量有减少的趋势。60天后，硝态氮含量、铵态氮含量、无机氮随水浸液浓度增加的变化趋势与30天时相似；随着花椒叶水浸液浓度的增加，氨化细菌、固氮菌的数量显著减少，硝化细菌数量、反硝化细菌数量仍呈减少趋势；土壤脲酶、蛋白酶活性与第30天的变化趋势相同。第60天与第30天的结果相比，相同水浸液浓度处理的硝态氮、铵态氮、无机氮均有下降的趋势，但除了25g.L－1水浸液处理的外，其它相同浓度的处理间差异均不显著；除了12.5 g.L的处理外土壤脲酶活性均呈增强的趋势；蛋白酶活性都有不同程度的增加；花椒叶水浸液处理的土壤硝化细菌和反硝化细菌数量呈增加趋势。 3．随着花椒叶水浸液浓度的增加，显著抑制了苜蓿根长、地上地下生物量、叶绿素含量、叶片中可溶性蛋白的含量，净光合速率。苜蓿体内四种抗氧化酶（POD、SOD、CAT、APX） 活性随着水浸液浓度的增加而降低，而丙二醛含量则增加。苜蓿氮初级同化相关酶硝酸还原酶（NR）、谷氨酰合成酶(GS)、谷氨酸脱氢酶（GDH）的活性随着水浸液浓度的增加受到不同程度的影响。总的来说，苜蓿硝酸还原酶、谷氨酰合成酶的活性受到抑制，而谷氨酸脱氢酶活性的变化则比较复杂，根呈先降低后增加的趋势，叶片则无显著变化。外施两种不同浓度的硝酸铵氮肥后，对12.5、25 g.L－1花椒叶水浸液处理的苜蓿化感作用有显著的缓解作用，表现在株高、生物量、光合作用等方面，大多达到与对照（0 g.L－1）未施氮肥无显著差异的水平，而对50 g.L－1水浸液处理的苜蓿幼苗，虽有一定的缓解作用，但这种作用均未达到与对照（0 g.L－1）未施氮肥时无显著差异的水平。 4． UV-B增强辐射处理花椒后，花椒的化感潜力显著增强。花椒叶片内UV-B吸收物质的含量和总酚含量均显著增加。 In recent years, with profound research on the reasons of continuous cropping obstacles, allelopathy received increasing attention to many scholars at home and abroad. Zanthoxy bungeanum as a Rutaceae plant is a high economic value species which gains early and uses widely. Zanthoxylum is an important economic crop in the arid valley of western Sichuan region, and its not even has received much concern for the continuous cropping obstacles. The systematic study of allelopathy of Zanthoxylum will contribute to the understanding and final settlement of this issue. The major allelopathic composition was separated through the extraction, chromatography combined with other methods. The impact on soil nutrient cycling was also studied through the addition of different concentrations of water extracts of Zanthoxylum. Furthermore, the effects of water extracts of Zanthoxylum leaves on alfalfa leaf physiological and biochemical indexes, photosynthesis, soil enzymes and nutrient uptake of nitrogen and the mitigation of allelopathy through using external fertilizer were studied to put forward scientific resolvent for Zanthoxylum continuous cropping obstacles .The response of allelopathic potential of Zanthoxylum to global change - UV-B enhanced radiation was studied . The main findings are as follows: 1. Through extraction with different polar organic solvents on concentrated water extract of Zanthoxylum leaf and then using column chromatography combined with detection of biological activity, one of the main allelopathic components- methoxy-phenol was isolated. The biological activity testing of the pure material of methoxy-phenol proved that it does have allelopathic potential. 2. Thirty days after treating soil with water extract of Zanthoxylum leaf, as compared with the control, the contents of soil nitrate, ammonium, nitrate plus ammonium nitrogen showed a trend of decrease with the increase of the concentration of water extract whereas the content of ammonium nitrogen showed a significant reduction, and the content of nitrate did not change significantly, the content of nitrate plus ammonium nitrogen also showed a significant (P <0.05) redction. The activity of soil urease and protease showed the same trend as the content of nitrate nitrogen plus ammonium nitrogen. With the increase in the concentration of water extract, the number of ammonification bacteria significantly reduced but nitrogen-fixing bacteria did not change significantly and there was a decreasing trend in the number of nitrifying bacteria and denitrifying bacteria. Sixty days after the treatment, with the increase in solution concentration of water extract of Zanthoxylum leaf, the content of nitrate、 ammonium nitrogen, nitrate plus ammonium nitrogen showed a similar change trend to 30 days’; the number of ammonification bacteria, nitrogen-fixing bacteria significantly reduced ; the number of nitrifying bacteria, denitrifying bacteria was still an downward trend; the activity of soil urease and protease showed the same trend as the 30th days’. Compared to the results of the 30th days’, the content of nitrate, ammonium, nitrate plus ammonium nitrogen showed a decrease trend between the treatment of same concentration, but there was no significant difference except the treatment of 25g.L-1 between the same concentration; the activity of soil urease showed enhanced trend except the treatment of 12.5 g.L-1; the activity of protease increased to varying degrees; the number of ammonification bacteria、 nitrifying bacteria and denitrifying bacteria were growing while nitrogen-fixing bacteria reduced.. 3. With the increase of the concentration of water extract of Zanthoxylum leaf, the water extract significantly inhibited the root length, aboveground biomass, content of chlorophyll and soluble protein in leaf and net photosynthetic rate. The activity of four antioxidant enzymes (POD, SOD, CAT, APX) reduced with the increase in concentration of the water extract but the content of MDA increased. The activity of enzymes related to primary nitrogen assimilation such nitrate reductase (NR), glutamyl synthetase (GS), glutamate dehydrogenase (GDH) were subject to different degrees with an increase in the concentration of water extracts. In general, the activity of nitrate reductase, glutamyl synthetase were inhibited, while change in the activity of glutamate dehydrogenase was more complex. The activity of glutamate dehydrogenase in leaf was first reduced and then increase,but did not change significantly in root. After using two external different concentrations of nitrogen fertilizer, there was a significant mitigation in inhibiton in plant height, biomass, photosynthesis, etc. in the treatment of 12.5,25 gL-1 of water extract of Zanthoxylum leaf, and most of these indexes showed no significant difference with the control (0 g.L-1, no external fertilizer was added) .Although there showed a certain degree of ease in the treatment of 50 g.L-1 , there was still a significant difference compared with the control (0 gL-1) in which no external fertilizer was used. 4.The allelopathic potential of Zanthoxylum positively responded to enhanced UV-B significantly. The content of UV-B absorbing compounds and the total phenol also significant increased.

氮肥对黄瓜根际土壤线虫群落组成、结构及其多样性的影响

土壤线虫是土壤动物的主要功能类群之一，在土壤养分分解和循环中起到重要的作用。本研究通过施用两种形态氮肥，硝态氮(NO-3–N)和铵态氮(NH+4–N)，对黄瓜整个生长期内根际土壤线虫的群落组成、结构及其多样性等的影响进行了比较研究。为增进土壤健康，提高土壤质量以及合理施用氮肥提供科学的理论依据。研究结果如下： 1. 氮肥处理后，不同浓度NO-3–N处理提高了根际土壤线虫数量，而NH+4–N处理（202.5 kg N/ hm2）抑制了线虫数量的增加。线虫群落结构相对较稳定，营养类群变化不大。且少量优势科/属会对土壤线虫群落特征起着至关重要的作用。 2. 在整个生长季节内，非寄生线虫的群体动态变化与寄生线虫的群体的动态变化具有相反的变化趋势。其中，NO-3–N处理和NH+4–N处理后植物寄生线虫出现频率的变化趋势相近，都是由高到低；非植物寄生线虫出现频率的变化趋势则都是由低到高。这说明非植物寄生线虫数量增长和空间占位对植物寄生线虫群体有一定的抑制作用。另外，也反映了适量氮肥在一定程度上能够减轻植物寄生线虫对黄瓜的危害。 3. 由多样性指数变化可知，NO-3–N和NH+4–N在低肥（67.5 kg N/hm2）和高肥（202.5 kg N/hm2）处理较中肥（135.0 kg N/hm2）处理，更不利于提高土壤线虫多样性地提高和线虫群落的稳定性。中肥不同形态氮肥处理与对照相比，H´指数在初花期和结果期显著增加了土壤线虫的H´指数，说明施入两种形态的氮肥能够提高线虫生物多样性程度。NH+4–N处理在初花期和结果期显著降低了土壤线虫种类的丰富性。土壤线虫生物多样性变化中，H´和SR指数在一定程度上能够反映施用无机氮肥对土壤线虫的多样性的影响，而J指数和λ指数效果不明显。NO-3–N和NH+4–N处理相比较，NO-3–N处理对黄瓜土壤线虫的多样性指数影响更大，促进了土壤线虫群体的多样化和种类的丰富度，更有利于提高土壤线虫的多样性，增加其稳定性。这些结果表明适量无机氮肥特别是NO-3–N的施用对黄瓜土壤线虫的生物多样性有一定的维护和提高作用。 4. 线虫数量与土壤质量指标的相关分析表明：线虫数量与有关土壤理化生指标，如土壤NO-3–N、NH+4–N、有机质含量等的正相关程度高，与总酚含量等显著负相关；与根际土壤微生物，细菌、真菌、放线菌数量等呈显著正相关。另外，线虫数量与土壤含水量未表现出显著相关关系。 Nematodes play a major role in decomposition and nutrient cycling in soil. Nematode community analyses are useful in assessing soil ecosystem status and function. The effects of two forms of mineral nitrogenous fertilizers (NO-3–N and NH+4–N) on nematode community composition, structure and diversity in rhizosphere of cucumber were investigated during different growing seasons of cucumber. Systematically research of effects of nitrogenous fertilizers could help to obtain better undstanding of a healthy soil and using nitrogenous fertilizers in reason. The main results are as follows: 1. The total numbers of nematode were more abundant in NH+4–N treatments than other teatments. However, NH+4–N teatment（202.5 kg N/hm2）dramatically inhibited it. All the tropic groups in the soil nematode communities were stable, and the dominant family or genus had an important function in the nematode community structure. 2. There was similar trend of the frequency of plant parasitic nematodes between NO-3–N and NH+4–N treatment, the similar trend of the frequency of non-plant parasitic nematodes was also found. But the frequency of plant parasitic nematodes exhibited a contrary trend to that of plant parasitic nematodes after different nitrogenous fertilizer treatments. The results showed that the increasing trend of the frequency and the niche of non-plant parasitic nematodes inhibited the plant parasitic nematodes, and indicated that right chemical fertilizers dosage could abate plant parasitic nematodes harm to cucumber. 3. The changes of the biodiversity index showed that the nitrogen treatment（135.0 kg N/hm2）promoted the stabilization of soil nematode diversity than other nitrogen treatments(67.5 kg N/hm2 and 202.5 kg N/hm2). In the treatment（135.0 kg N/hm2）,The changes in nematode diversity between the control plots and treated plots were compared by the biodiversity index (H´, J, SR, λ). Among these tested index, H´ and SR were effective in reflecting the effects of different nitrogenous fertilizers on the diversity of soil nematodes. In comparison with the NH+4–N treatment, the NO-3–N treatment promoted the stabilization of soil nematode diversity. 4. Correlation coefficients between nematode abundance and soil quality indices indicated that the total numbers of nematode were affected positively by NO-3–N, NH+4–N and the organic matter, and negatively by total phenolic acids; the total num- bers of nematode had positive correlation with bacteria, fungi and actinomycetes nu- mbers. Soil water contents had only a weak negative influence on it.

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.

川西亚高山两种针叶树幼苗对增温和施氮的响应

人类活动引起全球大气中温室气体（CO2、CH4、NOx）浓度不断增加，致使地球表面温度在过去的100 年中已经增长了0.74 ± 0.18℃，预计到本世纪末将会增加1.1-6.4℃。此外，氮沉降也是当今社会的重要环境问题，随着经济发展的全球化, 高氮沉降也呈现出全球化趋势。全球气候变暖和氮沉降给陆地生态系统的地上、地下生物学和生物地球化学过程所带来巨大影响越来越引起人们的关注。 本文以川西亚高山针叶林的两个重要树种云杉和油松幼苗为研究对象，采用红外辐射增温（空气增温2.1℃，土壤增温2.6℃）和根部施氮（施氮量25 g N m-2yr-1）的方法，从生长形态、光合作用、抗氧化能力和矿质营养等方面研究这两种幼苗对气候变暖和氮沉降的响应。该实验为室外控制实验，包括四个处理：(1)不增温+不施氮（UU）；(2) 不增温+施氮（UF）；(3) 增温+不施氮（WU）；(4) 增温+施氮（WF）。本研究旨在从生理生化、物质代谢 、生长及形态等不同水平上研究模拟增温和施氮对两种树苗的联合效应，提高我们对全球变化下亚高山针叶林早期更新过程的理解，同时也为森林管理提供科学依据。具体研究结果如下： 单独增温处理显著提高了云杉和油松幼苗的地茎、叶重、茎重、根重以及总生物量；单独施氮处理也增加了两种幼苗的株高和总生物量。而增温和施氮联合作用对两种幼苗生长的影响并不相同，联合作用对云杉幼苗生长指标的正效应显著低于单独施氮处理，但是联合作用比单独增温或施氮更大程度的促进了油松幼苗生物量的积累。 单独增温和施氮都有利于提高云杉和油松叶片中叶绿素含量、净光合速率(A)、最大净光合速率(Amax)、表观量子效率（Φ）、最大光能转化效率（Fv/Fm）和量子产量（Y）。与对两种幼苗生长指标的影响相似，加氮和增温共同作用下油松幼苗的以上光合指标比在单独增温或施氮处理下有更大程度的提高；而联合作用下云杉幼苗叶绿素含量、净光合速率、最大净光合速率、表观量子效率、最大光能转化效率以及量子产量比单独施氮处理明显地降低。 增温和施氮都显著地降低了云杉和油松幼苗针叶组织中活性氧和丙二醛的积累。交互作用降低了云杉幼苗叶片的抗氧化酶活性、脯氨酸和ASA 的含量，却显著提高了油松幼苗SOD、POD、APX 等抗氧化酶的活性，并且对油松幼苗脯氨酸和ASA 积累的促进作用比单一因子更加明显。因此，增温和施氮共同作用下油松幼苗叶片中O2-产生速率、H2O2 及MDA 含量明显降低，而云杉叶片中只有O2-产生速率出现降低趋势。 增温和施氮都降低了云杉体内的P、Ca、Mg 元素的含量，增加了Cu、Zn、Mn 在各器官内的积累。对油松幼苗而言，增温和加氮单独作用也显著降低了Ca 含量增加了Cu、Zn、Mn 的积累，但是不同于云杉幼苗的是P、Mg 也显著增加。增温和施氮联合作用对云杉幼苗体内元素的影响与单一施氮处理或增温处理相似，不同的是比单一因子作用更为明显降低了P、Ca、Mg 含量，增加了植株中N、Cu、Zn、Mn 的含量，但是油松矿质元素含量在联合作用下并没有产生类似于云杉幼苗的双因子叠加效应。 总之，尽管单独增温或者施氮都有利于云杉和油松幼苗生长指标、光合能力以及抗氧化能力的提高。但是，增温和施氮对云杉幼苗生长生理的促进效应非但没有在交互作用下有更大的提高，反而低于单独氮处理。与此不同的是，增温和施氮联合作用比单因子作用更有利于油松幼苗生长及生理指标的提高。 With the continued increase in atmospheric concentrations of greenhouse gases (CO2、CH4、NOx), the mean global surface temperature has increased by about 0.74 ± 0.18℃ over the past century and is predicted to rise by as much as 6.4℃ during this century. Besides global warming, nitrogen deposition is another serious environmental problem caused by human activities, and high nitrogen load has become globalization as a result of global economy development. Global climate warming and nitrogen deposition have induced dramatic alternations in above - and below- ground biology and biogeochemistry process in terrestrial ecosystems, and more and more attention has been invited to those problems. This experiment mainly studies two important species Picea asperata and Pinus tabulaeformis in subalpine coniferous forest of western Sichuan, China. Infared heaters are induced to increase both air and soil temperature by 2.1℃ and 2.6 ℃, respectively. Ammonium nitrate solution (for a total equivalent to 25 g N m-2 year-1) is added to soil surface. There are four treatments in this study: (1) unwarmed unfertilized (UU); (2) unwarmed fertilized (UF); (3) warmed unfertilized (WU); (4) warmed fertilized (WF). This study is conducted to determine the influences of experimental warming and nitrogen fertilization on physiolchemistry, nutrition metabolism, growth and morphology in the two coniferous species seedlings. The current study is favorable for increasing our understanding on the early phase of regeneration behavior in subalpine coniferous forest, and it also provide scientific direction for forest management under future global changes. The results are as follows: Artificial warming alone significantly increased basal diameter, leaf mass, stem mass, root mass and total biomass for Picea asperata and Pinus tabulaeformis seedlings, and single nitrogen fertilization are also favorable for growth of the two species and stimulate plant hight and total biomass. The two species seedlings respond differently to the combination of elevated temperature and nitrogen addition. Warming combined with nitrogen fertilization weakens the positive effects of nitrogen addition for growth of Picea asperata seedlings. However, the combination of elevated temperature and nitrogen fertilization further increase biomass accumulation of Pinus tabulaeformis seedlings. Both elevated temperature alone and nitrogen fertilization alone can increase photosynthetic pigments contents, net photosynthetic rate (A), maximum net photosynthetic rate (Amax), apparent quantity yield (Φ), maximum photochemical efficiency of photosystem II (Fv/Fm) and effective quantum yield (Y). Similarly with growth parameters, the combination of warming and nitrogen addition induced more increment of these above photosynthetic parameters for Pinus tabulaeformis seedlings. However, these photosynthetic parameters of Picea asperata seedlings under the combination of warming and nitrogen addition are lower than those under nitrogen fertilization alone. The levels of active oxygen species (AOS) and malodiadehyde (MDA) in needles of the two coniferous species seedling are obviously decreased by experimental warming or additional nitrogen. Warming combined with nitrogen fertilizer reduces the activities of SOD, CAT and APX, and the contents of proline and ASA of Picea asperata seedlings, but the combination significantly increases activities of these antioxidant enzymes in needlels of Pinus tabulaeformis seedlings and further improves the accumulation of proline and ASA compared to either artificial warming or nitrogen addition. Therefore, the rate of O2 - production, the contents of H2O2 and MDA in needles of Pinus tabulaeformis seedlings are remarkably reduced by the combination of warming and nitrogen addition, but the combination only significantly decreased the rate of O2 - production of Picea asperata seedlings. Elevated temperature or nitrogen fertilization decrease the contents of P, Ca, Mg but increase Cu, Zn, Mn contents for Picea asperata seedlings. For Pinus tabulaeformis seedlings, elevated temperature alone and nitrogen fertilization alone decreased Ca, but increased P, Mg, Cu, Zn, Mn contents. The effects of the combination of warming and nitrogen addition on these element contents in needles of Picea asperata seedlings are added or multiplied the effects of warming and nitrogen addition alone, resulting in less contens of P, Ca, Mg and more contents of Cu, Zn, Mn than either elevated temperature or nitrogen fertilization. Howere, these adding or multipluing single-factor effects on contents of these elements are not observed in the case of Pinus tabulaeformis seedlings. In conclusion, growth parameters, photosynthetic capacities and antioxidant abilities of Picea tasperata and Pinus abulaeformis seedlings are improved by experimental warming or nitrogen fertilization. Interestingly, the positive effects of warming and nitrogen addition on growth and physiological performances are not multiplied by the combination of elevated temperature and nitrogen fertilization, even dempened for Picea asperata seedlings. However, for Pinus tabulaeformis seedlings, growth and physiological performances are further improved by the combination.

牦牛粪便对青藏高原东部高寒草甸土壤养分系统的影响

川西北高寒草甸位于青藏高原东部地区，是我国四大牧区之一，也是长江和黄河等江河源区的重要水源涵养功能区。近几十年来，大量牦牛粪便被牧民作为生物能源、肥料或者食用菌产业的原料而利用，为草原生态系统的养分平衡增加了生态风险。鉴于在青藏高原地区针对牦牛粪便的相关研究尚未见报道，本文从粪便和土壤养分相互变化趋势的角度出发，研究了粪便在夏秋两季的分解状况和粪便其下及其周围土壤的养分变化。通过此研究，将有助于了解牦牛粪便在自然状态下的分解速率以及粪便对土壤养分及土壤微生物生物量的影响，为粪便对草地土壤生态系统的贡献提供概念性认识，同时也为高寒草甸草地这种脆弱生态系统的可持续管理提供理论依据。 针对牦牛粪便自身养分释放及其对土壤在时间和空间尺度上的影响，本文通过模拟牛粪堆积，在不同时间和固定区域内对牛粪和土壤进行了夏秋两季的采样测定，分析了牛粪及土壤NO3--N、NH4+-N、速效K、无机P、有机C、全N 和全P 含量随时间的变化趋势。得到如下结果： 1. 在研究区域内，牛粪对草地生态系统具有较强的养分（N、P）贡献能力。据初步统计，其估值大致为氮素699~932 kg ha-1，P 素为110~147 kg ha-1。牛粪（湿重、干重）在夏秋季节的分解速率具有较大差异，夏季显著快于秋季。夏季牛粪湿重、干重在2 个月左右之后分别降为初期的14%和24%，而秋季同期分别降为35%和52%。牛粪养分（NO3--N、NH4+-N、速效K、无机P、有机C、全N 和全P）的分解速率在夏季也要显著快于秋季。秋季经过2 个月左右的分解之后，牛粪以上含量分别降至初始态的32%、60%、36%、64%、58%、63%和43%，远高于夏季的同期水平。 2. 在不同季节，牛粪周围的土壤养分（NO3--N、NH4+-N、速效K 和无机P）含量变化随时间改变呈现相同的趋势。但是，牛粪周围不同远近下土壤养分随时间的动态变化幅度略有不同。粪下土壤养分含量随时间变化波动较大，距粪便越远，随时间变化的变幅越为平缓。总体来说，在夏季由于粪便分解较快，对土壤养分的持续作用时间不及秋季，秋季粪便分解变慢，表现出养分的缓释特征。其次，牛粪对粪下土壤影响的持续时间也长于对周围土壤的作用时间。 3. 粪便对土壤养分（NO3--N、NH4+-N、速效K、无机P）影响的范围在不同季节具有差异。夏季要高于秋季，但对周围土壤养分影响的持续时间低于秋季。在夏季短期内，牛粪对土壤NO3--N 和速效K 含量的影响范围能够超过30cm，而对NH4+-N 和无机P 的影响范围则介于10cm 和30cm 之间。在2 个月左右之后，牛粪对周围土壤养分的影响能力基本消失。在秋季，牛粪对周围土壤养分影响范围难以达到30cm 处。粪便在夏季对其下土壤和周围土壤的有机C、全N 和全P 含量并无显著影响，但在秋季能显著增加其下土壤有机C、全N 和全P 含量。 4. 牛粪在秋季对土壤SMB-C、SMB-N 和SMB-P 含量的影响能够持续2 个月以上，由于秋冬季节牛粪分解缓慢，因此推断这种效应持续时间至少能够1 年左右。另一方面，牛粪在秋季对土壤SMB-C、SMB-N 和SMB-P 含量的影响范围主要集中在其下土壤，而周围的影响效应并不明显。 The grassland on the eastern fringe of Qinghai-Tibetan Plateau was one of the four greatest pasture zones in our country and the main water conservation function zones in the hesastream of Yangtse River and Huanghe river. Rencent years, lots of dung in this area was used as biological energy, fertilizer or material of fungoid growing, leading to high risk of nutrient banlance in grassland ecosystem. In view of the researches on the impact of yak dung in this area are relatively rare, the present study focused on the relationship of dung and soil nutrient transformation in sunmer and autumn, which could profoundly illuminate the mechanism of dung decomposition and the effect of dung on soil chemical properties and soil microbe biomass. The present study also contributed to a basic understand and provided scientific management in the high-frigid ecosystem. Decomposition of yak dung and its effect on soil chemical properties in eastern grassland of Qinghai-Tibetan Plateau were determined. The study simulated the real dung pats, took dung and soil samples at different time and fixed-point in summer and autumn. The samples were analysed for NO3--N, NH4+-N, available K, inorganic P, total organic C (TOC), total N (TN), total P (TP). It was concluded that: 1. In study area, the yak dung supplied to ecosystem substantial nutrient. It is estimated that the N contribution of dung was approximately 699~932 kg ha-1, P contribution was approximately 110~147 kg ha-1. The rate of yak decomposition was more rapid in summer than autumn, the wet and dry weight of yak decreased to 14% and 24% respectively after 2 months when dung excreted in summer, with 35% and 52% in autumn. The content of NO3--N、NH4+-N、available K、inorganic P、TOC、TN and TP in dung decomposed more rapid in summer too. After 2 months when dung excreted in autumn, the content of above nutrient decreased to 32%、60%、36%、64%、58%、63% and 43% respectively，which were significantly higher than summer. 2. The content of NO3--N、NH4+-N、available K and inorganic P in soil around dung had the same transformation trend in each season, whereas it was distinguishing at different gradient of distance from dung, the nutrient in soil below dung had the most significant change while the more far from dung, the less change in soil. It was concluded that the yak dung had prolong impacts on soil in autumn compared with summer, besides, it aslo showed that the yak dung had protract effect on soil below dung compared with soil around dung. 3. The yak dung had expansive impact on soil around dung in summer whereas had relatively short effect compared with autumn. In short-term at summer, there was a significant increase about the content of NO3--N and available K around 30cm radius from dung pat while the content of NH4+-N and inorganic P between 10cm to 30cm. After 2 months, the impact almost disappeared. In autumn, the effect was hard to reach 30cm. The yak dung had no significant effects on the content of TOC、TN and TP in soil below or around dung in summer whereas there was a obvious increase in soil below dung pat in autumn. 4. The duration of effect of yak dung on soil microbial biomass(SMB) C、N and P was at least 2 months, maybe even more than 1 year. On the other hand, the impact of dung on SMB-C、SMB-N and SMB-P mainly acted on soil below dung while no obious effect on soil around dung.

不同小麦品质类型与生态环境关系的研究

小麦（Triticum aestivum L.）是世界上种植面积最大，总产量最高，食物加工种类最丰富的粮食作物，占世界人口35 ％－40 ％的人们以此为主要食物。因此小麦产量的高低和品质的优劣直接影响人们对食物需求的安全和满意程度，也影响着人类的营养平衡以及面粉和食品加工业的发展。随着生活水平的提高，人们对于小麦的品质越来越重视。培育优质专用小麦新品种，制定优质专用小麦品种品质生态区划，从而在不同程度上实现小麦的区域化种植和产业化经营具有重要的意义。 影响小麦品质的因素主要是遗传因素和环境因素，其中环境因素又包括各种自然生态因素和人为因素。研究表明，小麦品质的环境间的差异大于品种间的差异，气候条件是影响小麦品质的最重要的因子，小麦品质的地域间的差异反映出了小麦的品质区域分布规律。为了满足市场对不同品质小麦的需求，对小麦进行区域化研究具有重要的理论和现实意义。本研究结合四川的地理、气候特点，研究不同品质类型与生态环境的关系，为在复杂的生态环境内进行品质区划提供依据。 本研究首先根据四川省小麦种植区域的生态特点，在四川省多个典型生态区：川南丘陵的荣县、川西南高原的西昌、川西平原的双流布点种植，采用的小麦试验材料为不同品质类型：中筋小麦川育12、川育14、川育16由本所提供；弱筋小麦川麦32和强筋小麦川麦36由四川省农科院作物所提供。通过研究品质性状与品种及各个生态因子包括地点、土壤土质差异等的关系，明确不同生态环境中适宜种植的小麦品种类型，强筋小麦、中筋小麦更适合于在荣县、双流地区种植，弱筋小麦更适合于在西昌地区种植，为品种品质区划奠定基础。 其次，选择了本课题组育成的稳定中间品系，对其品质性状SDS沉降值进行了多年测定。分析了品质性状SDS沉降值与多种气候因子的相关性，结果表明SDS沉降值与日均温、日照时数成正相关，与降水量成负相关，为品质育种提供了理论依据。 此外，以中筋小麦新品种小麦川育14为材料，应用三元二次正交旋转回归模型设计试验，研究主要栽培因子播期、密度和施肥量对产量的影响，并建立函数模型。经计算机模拟寻优，筛选出了高产高效栽培组合措施，并确定了置信域。结合四川省不同的地理情况，在平原和丘陵地区分别进行实验，并各自建立了高产高效栽培组合措施，为川育14品种的推广提供了理论指导。 Wheat is one of the most important crops in the world. About 35%-40% people all over the world, take the wheat as their most important food. So the quality, as well as the quantity of the wheat makes a direct effect on people’s demands of food and their satisfaction. It also effects on human’s healthy, and the development of the Food processing industry. With the development of the living standard, people pay more attention to the quality of wheat. So, we set a special ecology zoning for wheat. It is significant to carry out planting the wheat in special zoning in varying degrees. The main factors affecting wheat quality are heredity and environment including many ecological factors and the factors in cultivation. As to the quality，the difference between ecology and cultivation is more important than the difference between special wheat. In so many factors, climate is the most important one. From the difference in quality between different zones，we can conclude the rule of distribution abort quality of wheat. Finding out the intersection of numerous wheat not only can meet the demand of food production，but also has important signification in theory and realism。In our research, according to the complex geography in Sichuan province, we study the relationship between numerous kinds of quality characters in wheat and the ecology. So, we can set a foundation for more research. In this research, firstly, we plant wheat in some typical ecological regions of SICHUAN province: RONGXIAN（south of SC）、XICHANG（south of SC）, SHUANGLIU(west of SC). The materials of the experiments: ChuanYu12, ChuanYu14, ChuanYu16(from our institute), Chuanmai32, Chuanmai36 (from the Chinese academy of agriculture sciences of Sichuan. Through the research on the relationship between the quality of wheat and those ecology factors, we can make a definition that which area is perfect matched with which kind of wheat. And it can satisfy the demand of people. Secondly, select many sorts of wheat from our research group. All of them are selected and bred more than 3 years(2003-2005). And we make every-year determination as well. We’ve gotten SDS value from those 9, and various data on factors of climate. We also got to know the relation ship between those numbers. Thirdly, use Chuanyu14 as material, the mathematical model of the relation between the production of wheat and main agricultural measures such as date, density and fertilizer. The model was established by association of three elements two return, rotate and regression. We set a suitable model and get a suitable method which can make high harvest. Based on various kinds of geographical regions in Sichuan province, we set different models which can be used in plain and hill. So, we can plant Chuan Yu 14 in Sichuan province under the result in research.

簇毛麦（ Dasypyrum villosum）矮秆突变体的研究

株高是农作物的重要农艺性状之一，适度矮化有利于农作物的耐肥、抗倒、高产等。20世纪50年代，以日本的赤小麦为矮源的半矮秆小麦的培育和推广，使得世界粮食产量显著增长，被誉为“绿色革命”。迄今为止，已报到的麦类矮秆、半矮秆基因已达70多个，但由于某些矮源极度矮化或者矮化的同时伴随不利的农艺性状，使得真正运用于育种实践的矮源较少。因此，发掘和鉴定新的控制麦类作物株高的基因，开展株高基因定位、克隆及作用机理等方面的研究，对实现麦类作物株高的定向改良，具有重要的理论意义和应用价值。簇毛麦(Dasypyrum villosum，2n＝14，VV)是禾本科簇毛麦属一年生二倍体异花授粉植物，为栽培小麦的近缘属。本课题组在不同来源的簇毛麦杂交后代中发现了一株自然突变产生的矮秆突变体。观察分析了该突变体的生物学特性，对矮秆性状进行了遗传分析，对茎节细胞长度、花粉的活力进行了细胞学观察，考察了该突变体内源赤霉素含量及不同浓度外施赤霉素对突变体的作用，分析了赤霉素生物合成途径中的内根贝壳杉烯氧化酶（KO）和赤霉素20氧化酶(GA20ox)的转录水平，对赤霉素20氧化酶和赤霉素3-β羟化酶(GA3ox)进行了克隆和序列分析，并对GA20ox进行了原核表达和表达的组织特异性研究。主要研究结果如下：1. 该突变体与对照植株在苗期无差异，在拔节后期才表现出植株矮小，相对对照植株，节间伸长明显受到抑制，叶鞘长度基本不变。在成熟期，对照植株的平均株高为110cm，而突变株的平均株高为32cm，仅为对照植株的1/3 左右。除了株高变矮以外，在成熟后期，突变株还表现一定程度的早衰和雄性不育。I2-KI染色法观察花粉活力结果表明，对照植株花粉90%以上都是有活力的，而突变植株的花粉仅20%左右有活力。2. 突变株与对照植株的杂交F1代均表现正常株高，表明该突变性状为隐性突变。F1代植株相互授粉得到的168株F2代植株中，株高出现分离，正常株高（株高高于80cm）与矮秆植株（株高矮于40cm）的株数比为130：38，经卡方检验，其分离比符合3：1的分离比，因此推测该突变体属于单基因的隐性突变。3. 用ELISA方法检测突变株和对照植株的幼嫩种子中内源性生物活性赤霉素（GA1＋3）含量，结果表明突变株的赤霉素含量为36 ng/ml，而对照植株的赤霉素含量为900 ng/ml。对突变株外施赤霉素，发现矮秆突变株的株高和花粉育性均可得到恢复。这些结果表明该突变株为赤霉素缺陷型突变。4. 用荧光定量PCR方法比较突变株与对照植株中内根贝壳杉烯氧化酶和赤霉素20氧化酶的转录水平，结果表明突变株的KO转录水平比对照植株分别提高了6倍（苗期）和16倍（成熟期），突变株的GA20ox转录水平与对照植株在苗期无明显差异，在成熟期突变株较对照植株则提高了10倍左右。这些结果表明该矮秆突变体与赤霉素的生物合成途径密切相关，而且极有可能在赤霉素的生物合成途径早期就发生了改变。5. 以簇毛麦总基因组为模板，同源克隆了GenBank登录号为EU142950，RT-PCR分离克隆了簇毛麦的GA3ox基因cDNA全长序列，分析结果表明该cDNA全长1206bp，含完整编码区1104bp，推测该序列编码蛋白含368个氨基酸残基，分子量为40.063KD，等电点为6.27。预测的氨基酸序列含有双加氧酶的活性结构，在酶活性中心2个Fe离子结合的氨基酸残基非常保守。该序列与小麦、大麦和水稻的GA3ox基因一致性分别为98%、96%、86%。基因组序列与cDNA序列在外显子部分一致，在478-715bp和879-1019bp处分别含238bp和140bp的内含子。6. 通过RT-PCR技术克隆了簇毛麦的GA20ox基因全长，命名为DvGA20ox，GenBank登录号为EU142949。该基因全长1080个碱基，编码359个氨基酸，具有典型的植物GA20ox基因结构。该基因编码的蛋白质与小麦、大麦、黑麦草等GA20ox蛋白的同源性分别为98%，97% 和91%。该序列重组到原核表达载体pET-32a(+)上，将获得的重组子pET-32a(+)-DvGA20ox转化大肠杆菌BL21pLysS后用IPTG进行诱导表达。SDS-PAGE分析表明，DvGA20ox基因在大肠杆菌中获得了高效表达，融合蛋白分子量为55kDa。定量PCR分析表明，该基因在簇毛麦不同器官中的表达差异明显：叶片中表达水平最高，根部表达水平次之，茎部和穗中表达较弱。在外施赤霉素后，该基因的表达水平在两小时以后急剧下降，表明该基因的表达受自身的反馈调节。本研究结果认为，(1)该簇毛麦矮秆突变体为单基因的隐性突变；(2)该矮秆突变体为赤霉素敏感突变，内源赤霉素含量检测表明突变体的内源性赤霉素含量仅为对照植株的1/30；(3)荧光定量PCR结果表明突变株的赤霉素生物合成途径的关键酶基因表达水平比对照植株高，而且突变植株的赤霉素生物合成改变很可能发生在赤霉素生物合成途径的早期；(4)GA20ox有表达的组织特异性，且受到自身产物的反馈调节。 Plant height is an impotrant agronomic trait of triticeae crops.Semi-dwarf cropcultivars, including those of wheat, maize and rice, have significantly increased grainproduction that has been known as “green revolution”. The new dwarf varieties couldraise the harvest Index at the expense of straw biomass, and, at the sametime, improvelodging resistance and responsiveness to nitrogen fertilizer. Moreover, dwarf traits ofplant are crucial for elucidating mechanisms for plant growth and development aswell. In many plant species, various dwarf mutants have been isolated and theirmodles of inheritance and physiology also have been widely investigated.The causesfor their dwarf phenotypes were found to be associated with plant hormones,especially, gibberellins GAs.Dasypyrum villosum Candargy (syn.Haynaldia villosa) is a cross-pollinating,diploid (2n = 2x = 14) annual species that belongs to the tribe Triticeae. It is native toSouthern Europe and West Asia, especially the Caucasuses, and grows underconditions unfavorable to most cultivated crops. The genome of D. villosum,designated V by Sears, is considered an important donor of genes to wheat for improving powdery mildew resistance, take-all, eyespot, and plant and seed storageprotein content. A spontaneous dwarf mutant was found in D. villosum populations.The biological character and modles of inheritance of this dwarf mutant are studied.The cell length of stem cell is observed. The influence of extraneous gibberellin tothe dwarf mutant is also examined; the transcript level of key enzyme of gibberellinbiosynthesis pathway in mutant and control plants is compared. GA3ox and GA20oxare cloned and its expression pattern is researched.1. The dwarf mutant showed no difference with control plants at seedlingstage.At mature stage, the average height of control plants were 110cm and the dwarfplants were 33cm. The height of the mutant plant was only one third of the normalplants due to the shortened internodes. Cytology observation showed that theelongation of stem epidermal and the parenchyma cells were reduced. The dwarfmutant also shows partly male sterile. Pollen viability test indicates that more than80% of the pollen of the mutant is not viable.2. The inheritance modle of this dwarf mutant is studied. All The F1 plantsshowed normal phenotype indicating that the dwarfism is controlled by recessivealleles. Among the 168 F2 plants, there are 130 normal plants and 30 dwarf plants, thesegregation proportion accord with Mendel’s 3:1 segregation. We therefore proposethat this dwarf phenotype is controlled by a single recessive gene.3. Quantitative analyses of endogenous GA1+3 in the young seeds indicated thatthe content of GA1+3 was 36ng/ml in mutant plants and 900ng/ml in normal plants.The endogenous bioactive GA1+3 in mutant plants are only about 1/30 of that innormal plants. In addition, exogenously supplied GA3 could considerably restore themutant plant to normal phenotype. These results showed that this mutant wasdefective in the GA biosynthesis.4. More than ten enzymes are involved in GA biosynthesis. KO catalyzes thefirst cytochrome P450-mediated step in the gibberellin biosynthetic pathway and themutant of KO lead to a gibberellin-responsive dwarf mutant. GA20ox catalyze therate-limited steps so that their transcript level will influence the endogenous GAbiosynthesis and modifies plant architecture. The relative expression levels of genesencoding KO and GA20ox were quantified by real time PCR to assess whether thechanges in GA content correlated with the expression of GA metabolism genes andwhere the mutant occurred during the GA biosynthesis pathway. In mutant plants,the transcript levels of KO increased about 6-fold and 16-fold at the seedling stage and elongating stage respectively comparing with the normal plants. For theseedlings, there was no notable difference in the expression of GA20ox betweenmutant and normal plants. At the elongating stage, GA20ox transcript increased 10times in mutant plants, suggesting that the GA biosynthesis pathway in mutant plantshad changed from the early steps rather than the late steps.5. A full length cDNA of D. villosum gibberellin 3β-hydroxylase homology(designated as DvGA3ox) was isolated and consisted of 1206bp containing an openreading frame of 1104bp encoding 368 predicted amino acid residues. Identityanalysis showed that the gibberellin 3β-hydroxylase nucleotide sequence shared 98%,96% and 86% homology with that of wheat, barley and rice. The predicted peptidecontained the active-site Fe of known gibberellin 3β-hydroxylase and the regionhomologous to wheat, barley and Arabidopsis. The genomic clone of gibberellin3β-hydroxylase has two introns.6. The full-length cDNA of D. villosum gibberellin 20 oxidase (designated asDvGA20ox) was isolated and consisted of 1080-bp and encoded 359 amino acidresidues with a calculated mol wt of 42.46 KD. Comparative and bio-informaticsanalyses revealed that DvGA20ox had close similarity with GA20ox from otherspecies and contained a conserved LPWKET and NYYPXCQKP regions. Tissueexpression pattern analysis revealed DvGA20ox expressed in all the tissues that wereexamined and the highest expression of DvGA20ox in expanding leaves followed byroots. Heterologous expression of this cDNA clone in Escherichia coli gave a fusionprotein that about 55KD. Transcript levels of DvGA20ox dramatically reduced twohours after application of biologically active GA3, suggesting that the biosynthesis ofthis enzymes might be under feedback control.

长期施肥对黄土旱塬区土壤—植物系统中氮、磷养分的影响

对1984年建立的长期试验田,分析了2005年小麦产量、养分吸收及土壤养分变化。结果表明,单施磷肥增产25.6%,单施氮肥增产48.1%,其吸氮、磷量也相应增加,但收获指数显著低于对照;氮磷配施增产幅度为101.3%3~02.8%,养分吸收量增加显著,最佳施肥量为N2P2(N 90 kg/hm2、P 56.4 kg/hm2)。施肥明显改变了耕层土壤养分的含量,也影响了养分在土壤剖面的分布。氮磷配施是培肥土壤的有效途径,耕层土壤全磷增加了8.3%~45.2%,速效磷增加54.8%9~17.8%。中等施氮(N 90 kg/hm2)水平下,随着磷的增加,耕层土壤全磷累积和施磷量的关系为y=0.002x-0.112。速效磷含量增加和磷肥用量的关系为y=9.6537Ln(x)-35.371,施肥对60 cm以下磷素影响较小。

施肥与品种及其种子大小对冬小麦光合及叶绿素荧光特性的影响

以土垫旱耕人为土为供试土样,采用4个冬小麦品种、3种播种方式和4种施肥方式进行盆栽试验,研究施肥、品种和种子大小对小麦叶片光合和叶绿素荧光特性的影响.结果表明:(1)在开花期和灌浆期,旗叶叶绿素相对含量(SPAD值)均为NP配施最高,其平均值分别比对照显著增加17.83%和13.01%;NP配施条件下,在开花期和灌浆期SPAD均为大粒单播较高并显著高于小粒单播;开花期和灌浆期SPAD分别以远丰998和咸农39最高并显著高于其它品种,平均比最低的白芒麦分别高17.68%和18.75%.(2)对旗叶净光合速率来说,开花期的NP配施处理比对照略有下降,而单施N和P分别比对照显著降低13.03%和23.17%,灌浆期的平均值以NP配施最高且比对照显著提高6.95%;小偃6号在开花期显著高于其余品种4.01%~6.19%(P<0.05),而白芒麦和咸农39则在灌浆期具有较明显优势,均分别显著高于其余品种约16.60%~26.91%;在开花期和灌浆期,2种单播方式平均值相近且显著高于混播方式.(3)就叶片Fv/Fm和Fv/Fo值而言,NP配施明显高于其它施肥处理,且NP均衡供应时远丰998和混播方式具有明显优势.可见,氮...

施氮和不同栽培模式对半湿润农田生态系统冬小麦根系特征的影响

在陕北黄土丘陵沟壑区对清耕和问作沙打旺(Astragalus adsurgens)6年、4年、2年仁用杏园0～500cm土层土壤水分、有机质、全氮、全磷、速效氮、速效磷、速效钾含量及树体生长状况进行了测定,结果表明,间作沙打旺,除了在秋季提高了0～100cm土层土壤水分以外,在春季、夏季和秋季均显著降低了0～500cm土层土壤水分,且间作沙打旺年限越长,降低越显著。间作沙打旺提高了0～100cm土层土壤有机质和全氮含量,间作年限越长效果越显著,但对100cm土层以下的土壤有机质和全氮无显著影响。间作沙打旺对土壤全磷含量无显著影响。间作沙打旺显著降低了土壤速效养分含量,其中速效氮降低深度达500cm土层,速效磷、速效钾达300cm土层,且间作年限越长,降低越显著。间作沙打旺显著削弱了树体的长势,降低了坐果率和杏仁产量。间作沙打旺存在着与仁用杏争水争肥的矛盾,黄土丘陵沟壑区仁用杏园不宜间作沙打旺。