Hypoosmotic shock induces a stateⅠtransition of photosynthetic apparatus in Dunaliella salina

The effects of hypoosmotic shock on state transition in darkness in Dunaliella salina were studied. When the concentration of NaCI in culture medium was dropped from 1.5 to 0.5 mol/L abruptly, the photosynthetic rate of D.salina declined, but the respiratory rate and intracellular ATP content increased in the dark. The FpsⅡ/FpsⅠ ratio at 77 K of D. salina cells exposed to hypoosmotic shock was higher than that of control cells, indicating that more excitation energy was distributed to PS Ⅱ in stressed D.salina cells upon illumination. A decrease in LHC Ⅱ phosphorylation level was also observed when D.salina was exposed to hypoosmotic shock. Thus a state Ⅰ transition of photosynthetic apparatus occurs when D.salina suffers hypoosmotic shock in darkness, which is supposed to be related to an enhancement of respiration and an increase in ATP content in stressed D.salina cells.     

Recombinant PsbF from Synechococcus sp. PCC 7002 forms β:β homodimeric cytochrome b559

All organisms with oxygenic photosynthesis contain two photosystems:photosystem Ⅰ(PSⅠ)and photo-systemⅡ(PSⅡ),The minimal photosystem Ⅱ particles which are photochemically active contain three subunits:D1,D2 and cytochrome b559 (Cyt b559),The function of Cyt b559 remains unclear,We have successfully overxpressed the psbF gene,encoding the β subunit of Cyt b559,from a marine cyanobacterium Synechoccous sp.PCC 7002 as a fusion gene and obtained a redox-active from of Cyt b559,When the N-terminal GST protein of the fusion gene product was removed with thrombin ,the PsbF protein was still redox-active,suggesting that the recombinant PsbF can form dimer in Escherichia coli.The absorption spectra of either the oxidized from or the reduced form of both GST fusion protein and the purified PsbF dimer and the difference Spectra between the two forms are the same as that of the Cyt b559 isolated from the higher plants .Redox titration analysis of recombinant PsbF showed that the mid-point redox potential of the recombinant Cyt b559 was approximately 50 mV, which is close to the low potential of Cyt b559 ,The results are helpful to the understanding of locatlization and function of Cyt b559 on thylakoid membranes.Ⅰ     

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。     

环境因子对东湖几种沉水植物生理的影响研究

报道了光照强度、水体温度及水体ＰＨ值对东湖５种沉水植生理的影响，实验结果表明，在一定温度范围内，５种植物的光补偿点均随温度的升高而上升，且种间有较大的差异。各植物光合色素的含量，受生态因子的影响，表现出一定的适应性。５种植物对水体高ＰＨ值耐受能力有明显的差异。     

中国南方红壤地区粮食作物气候生产潜力研究——以江西省为例

该文在前人全省农业分区的基础上，从计算每年进入各农业区土地生态系统的太阳幅射能开始，逐步计算出各农业区土地生态系统粮食作物生产的光合潜力、光温潜力和气候潜力，进而得到全省粮食作物的气候生产潜力总量．在分析江西省粮食作物生产现状的基础上，提出了发挥江西省粮食作物生产潜力的措施．     

蓝光对水稻幼苗生长及干物质积累的影响

研究蓝光对水稻幼苗生长及干物质重量的影响。结果表明，与白光及黑暗处理幼苗相比，蓝光处理的水稻幼苗较矮，第２叶鞘较短，第１叶片开张角度增大，叶片平展加快。     

管藻目绿藻刺松藻（Codium fragile）PSⅡ捕光？…

采用ＰＡＧＥ法对管藻目绿藻刺松藻的色素蛋白复合物进行了分离,并研究了４种主要的捕光复合物ＬＨＣＰ１,ＬＨＣＰ２,ＬＨＣＰ３和ＬＨＣＰ３的色素和光谱特性等;通过对最大的捕光复合物ＬＨＣＰ１的再分离,进一步得到了与其他３种小分子量捕光复合物相对应的条带,证明ＬＨＣＰ２,ＬＨＣＰ３和ＬＨＣＰ３都是国的组成成分,并提出管藻目绿藻的４种主要的捕光复合物之间并不象高等植物那样是单体和寡聚体的关系,而是分别以不     

温室生菜的光合特性及环境参数优化的试验研究

为探明温室生菜的光合作用与温室小气候之间的量化关系,以实验为基础,研究春、夏季玻璃温室条件下生菜的光合特性,分析温度、光照、ＣＯ２浓度、湿度等环境因子对光合作用的综合影响,初步建立了生菜的光合生产函数,从而可对环境因子进行优化组合以合理利用和调控气象资源测定和优化结果表明：生菜的光合速率在一定范围内随着光强和ＣＯ２浓度的增加而增加,但有一定的极限;夏季的光合速率日变化呈双峰曲线,在启用风机＋湿帘降温系统的情况下无午休现象;夏季较合理的调控参数为：温度３３℃,光强３５０００ｌｘ,相对湿度７５％