大粒小麦高产原因的探讨

以中粒小麦４１８５为对照品种,研究了不同大粒小麦品系在灌浆至成熟期间的光合性能、灌浆强度及最 产量。结果表明,大粒小麦的叶面积大,光合强度高,灌浆强度高,千粒重明显高于中粒品系,是有推广价值的高产品种。     

不同盐分在不同浓度条件下对玉米幼苗基础生理效应的研究

用一系列含同摩尔Ｎａ＾＋浓度的ＮａＣｌ、Ｎａ２ＣＯ３、Ｎａ２ＳＯ４溶液以及用磷酸中和至ＰＨ值与含同摩尔Ｎａ＾＋浓度的ＮａＣｌ溶液的ＰＨ值相等的Ｎａ２ＣＯ３溶液处理生长期为３０天的玉米幼苗。处理一周后,测定离子含量、渗透势、光合性能和叶绿素含量等各项生理指标。结果表明：在同摩尔Ｎａ＾＋浓度条件下,玉米幼苗在ＮａＣｌ、ＮａＣＯ３和Ｎａ２ＳＯ４胁迫下产生胁变的顺序为：Ｎａ２ＣＯ３〉ＮａＣｌ〉Ｎａ２ＳＯ４     

光合作用模型化合物的研究现状及发展趋势

光合作用模型化合物包括二元化合物、多元化合物和非共价键相连的超分子体系,超分子体系的光化学和光物理是近几年该领域的研究热点,目前,人们合成的光合作用模型化合物已经具备了自然界光合作用反应中心的某些性质,预计,今后该领域的研究工作将集中在固相和超分子体系模型化合物的研究上。     

Simulation for the primary electronic donor of photosystem Ⅱ in vitro

Histidine coordinated to Chl a is a distinct characteristic of Chl a in vivo. By using histidine analogue of 1-methylimidazole (C4H6N2) and measuring the UV/vis absorption, CD and MCD spectra of the interaction between C4H6N2 and Chl a in CCl4, we have obtained that: (ⅰ) In pure CCl4 solvent, Chl a molecule is in five-coordinate state, and two Chl a molecules form an asymmetric compact-dimer with strong coupling interaction. We propose that the two Chl a molecules are connected by two unequally coordinated Mg-O bonds (the two oxygen atoms come from the C== O of C131 keto and C17 ester, respectively); (ⅱ) when the molar ratio of C4H6N2/Chl a is 0.5 or 1 (corresponding to 2Chl a·1C4H6N2 and 2Chl a·2C4H6N2, respectively), significant changes have been observed in the absorption, CD and MCD spectra, which indicate that the Chl a remains in dimer form, but the coupling interaction between them reduces greatly. We postulate that C4H6N2 replaces the ligation of C== O of C17 ester and C131 keto to Mg atoms sequentially. The two Chl a molecules linked by two weakly interacted Mg...O bonds form a relaxed-dimer. The structure of the model is essentially similar to that of the primary electronic donor, P680, of photosystem Ⅱ in high plants and algae.     

Distribution of lanthanum among the chloroplast subcomponents of spinach and its biological effects on photosynthesis： location of the lanthanum binding sites in photosystem Ⅱ

The effects of lanthanum at different concentrations on the related photosynthetic activities of Hill reaction, Mg^2＋-ATPase and Ca^2＋-ATPase in spinach chloroplast were studied. Experimental results showed that lanthanum can increase all the activities at suitable concentration （15-30 mg· L^-1）, however, it behaves toxically on them when over used （60 mg. L^-1）. To get an improved understanding of the mechanism of lanthanum effects on the photosynthesis of spinach, the different subcomponents in the chloroplast of the cultured spinach were isolated, and the content of lanthanum in each subcomponent was determined by ICP-MS. The results obtained indicated that among these different subcomponents, about 90% out of the total chloroplast lanthanum was located in photosystem Ⅱ （PS Ⅱ） while there was little lanthanum in photosystem Ⅰ （PS Ⅰ）. Moreover, size exclusion high performance liquid chromatography （SE-HPLC） coupled with online UV and ICP-MS detections was novelly used for locating lanthanum binding sites in PS Ⅱ proteins for the first time. It was found that lanthanum has two binding sites in PS Ⅱ： La associates with chlorophyll together with magnesium in PS Ⅱ by partly replacing magnesium and also shares the common binding sites of PS Ⅱ proteins together with the inorganic cofactors of calcium and manganese, influencing the process of photosynthesis.     

光照对坛紫菜生长和无机碳利用的影响

］以坛紫菜Z-61品系为研究材料,分析坛紫菜叶状体和丝状体在三种光强（10,50,500 μmol·m-2·s-1）下的应答。发现:1）坛紫菜叶状体和丝状体的光系统 Ⅱ 最大量子产量及叶绿素a和藻红蛋白的含量都随光强增加而降低,但净光合速率、最大光合速率、胞外碳酸酐酶活性和总碳酸酐酶活性则随光强增加而增加。2）当光强从10 μmol·m-2·s-1增加到500 μmol·m-2·s-1时,坛紫菜叶状体的生长速率约增加77%;丝状体的生长速率先增加后降低,在光强500 μmol·m-2·s-1下达到最低,比在10 μmol·m-2·s-1下显著下降了约90%。3）在三种光强下,坛紫菜叶状体的最大光合速率、光系统 Ⅱ 最大量子产量和生长速率都大幅高于丝状体。这些结果表明:坛紫菜的光系统 Ⅱ、光合作用与生长对光强的应答并不完全一致;叶状体比丝状体更适应高光,这可能是长期进化的结果;光强可以改变坛紫菜对无机碳的吸收。     

麻栎光合作用的特性及其对CO2倍增的响应

研究了 1 2年生麻栎的光合作用特性、净光合速率的日变化及其对CO2 倍增的响应。结果表明 :( 1 )麻栎叶片的光饱和点约为 1 2 0 0 μmol/ (m2 ·s) ,光补偿点约为 50 μmol/ (m2 ·s) ,表观光量子效率为 0 .0 2 5mol/mol。麻栎叶片CO2 补偿点为 60 μmol/mol,CO2 饱和点为1 2 0 0 μmol/mol,叶片的羧化效率为 0 .0 2 ,麻栎为喜光的C3植物 ;( 2 )麻栎叶片的净光合速率日变化在生长初期和末期为单峰曲线 ,其走势与光合有效辐射走势一致 ;而在生长盛期为双峰曲线 ,净光合速率在中午出现了明显的下降 ;( 3 )主成份分析表明 ,影响麻栎净光速率的主导因子在生长初期是光强和叶室CO2 浓度 ,在生长盛期是饱和蒸汽压差和温度 ,在生长末期是饱和蒸汽压差和相对湿度 ;( 4 )CO2 倍增条件下 ,麻栎叶片净光合作用速率平均增幅为 89.1 7%。     

干旱和高温对植物胁迫效应的研究进展

干旱对植物的影响广泛而深刻，它可以表现在生长发育的各个阶段，如种子萌发、营养生长和生殖生长，直到开花结实．同时影响各种生理代谢过程，如光合作用、呼吸代谢、水分和营养元素的吸收转运、各种酶的活性和有机物质的转化、运输、积累等．本文概述了植物体对水分和高温胁迫做出的响应，既有生理上的，包括光合作用，呼吸作用，气孔行为等，又有形态结构方面的适应，并讨论了研究中存在的问题及对未来的展望．     

苏铁耐旱、抗寒及光合生理特性研究

采用干旱胁迫及人工模拟冷冻试验 ,进行苏铁耐旱、抗寒及光合生理特性研究 ,结果表明 :不同年龄苏铁的耐旱性、抗寒性及光合生理指标存在明显差异 ,随苏铁叶龄增加 ,苏铁叶片水势、冻害敏感指数和 NR活力下降 ,蒸腾速率、自然饱和亏和叶绿素含量增加 ,苏铁耐旱及抗寒性增强 ;苏铁水分及光合生理指标对干旱胁迫反应敏感 ,随干旱胁迫加剧 ,苏铁叶片水势、蒸腾速率、叶绿素、NR活力及净光合速率下降 ,而自然饱和亏增大 ,以适应胁迫环境 ,使苏铁表现出较强的抗旱性和生命力。     

铯对小麦叶片光合特性影响的研究

随着环境中铯(Cs)污染日益恶化,铯对生物毒害作用的研究受到越来越多的关注.为了探讨铯对植物光合作用的影响,在石英砂和Hoagland营养液培养体系下,从三叶期开始用浓度为0、0.5、1、5、10、20 mmol·L-1的133Cs+[CsCl]处理小麦(Triticum aestivum L.)幼苗.在处理后的第0、7、14、21、28 d时,检测小麦光合特性的改变.结果表明:用0.5 mmol·L-1和1 mmol·L-1低浓度133Cs+处理7 d后,小麦叶片的叶绿素含量、叶圆片放氧活性、类囊体膜电子传递活性均显著高于对照;但随133Cs+浓度的增加及处理时间的延长,这些参数的数值均显著下降.此外,光合系统II(PSII)活性的下降速率高于光合系统I(PSI)下降速率,说明PSII相对于PSI更容易受到133Cs+的胁迫伤害.这些结果表明133Cs+对小麦的毒害效应受时间和浓度的双重制约.低浓度133Cs+可以促进小麦光合作用,而高浓度133Cs+则显著抑制小麦光合作用.