稀土对肌质网Ca~（2＋）－ATP酶活性的影响

研究了镧、轧、镱及四种配合物对Ｃａ~（２＋）－ＡＴＰ酶活性的影响．结果表明,低浓度的Ｌａ~（３＋）,Ｇｄ~（３＋）和Ｙｂ~（３＋）对肌质网Ｃａ~（２＋）－ＡＴＰ酶有激活作用;随着其浓度的增加,它们对酶活性的抑制程度增大;而Ｌａ~（３＋）,Ｇｄ~（３＋）和Ｙｂ~（３＋）对纯化的Ｃａ２~（＋）－ＡＴＰ酶则只有抑制作用;Ｇｄ─Ｎ─乙酰─缬氨酸和Ｙｂ─丙氨酰代丙氨酸配合物对肌质网膜和纯化的Ｃａ~（２＋）－ＡＴＰ酶活性的影响与Ｇｄ~（３＋）及Ｙｂ~（３＋）类似,但其激活程度和抑制程度比Ｇｄ~（３＋）及Ｙｂ~（３＋）小;Ｇｄ─ＤＴＰＡ和Ｙｂ－ＤＴＰＡ对Ｃａ２~（＋）－ＡＴＰ酶活性基本无影响。     

苹果果肉质膜微囊主动动输Ca^2＋的Ca^2＋—ATP酶特性

应用＾４５Ｃａ＾２＋示踪法研究了苹果果肉质膜微囊依赖于Ｃａ＾２＋的ＡＴＰ酶（Ｃａ＾２＋－ＡＴＰ酶）活性与Ｃａ＾２运输之间的关系及激素对该酶活性的影响。结果表明：Ｃａ＾２＋－ＡＴＰ酶存在于质膜上并受载体Ａ２３８７刺激而活性增加,该酶活性与依赖于ＡＴＰ的Ｃａ＾２＋运输依抑制剂ＥＢ,游离Ｃａ＾２＋和ＡＴＰ浓度的变化并呈极为相似的饱和动力学特征,而其ＥＢ半抑制浓度,Ｃａ＾２＋和ＡＴＰ半饱和浓度分别为０．１     

苹果果肉质膜微囊主动运输Ca2+的Ca2+-ATP酶特性

应用４５Ｃａ２ ＋ 示踪法研究了苹果果肉质膜微囊依赖于Ｃａ２＋ 的ＡＴＰ 酶（Ｃａ２＋ＡＴＰ酶）活性与Ｃａ２＋ 运输之间的关系及激素对该酶活性的影响。结果表明：Ｃａ２ ＋ＡＴＰ 酶存在于质膜上并受载体Ａ２３１８７ 刺激而活性增加,该酶活性与依赖于ＡＴＰ 的Ｃａ２ ＋ 运输依抑制剂ＥＢ、游离Ｃａ２＋ 和ＡＴＰ浓度的变化并呈极为相似的饱和动力学特征;而其ＥＢ 半抑制浓度,Ｃａ２＋ 和ＡＴＰ 半饱和浓度分别为０ ．１ ,０ ．１ 和５０ μｍｏｌ／Ｌ,从而证实了正是Ｃａ２＋ＡＴＰ酶推动苹果果肉质膜微囊的Ｃａ２＋ 的主动运输。生长素与萘乙酸均可促进苹果果肉质膜微囊Ｃａ２＋ＡＴＰ酶活性和Ｃａ２＋ 吸收,而赤霉素则无此作用。     

玉米叶绿体atpB基因表达产物的特性及其抗体对CF_1功能的影响

利用大肠杆菌获得玉米叶绿体ａｔｐＢ融合基因及非融合基因的高效表达。从大肠杆菌中部分分离纯化得到的这些ａｔｐＢ基因表达产物都表现出微弱的水解ＡＴＰ的活力。由其中一种融合蛋白β_１制备得到的抗血清对菠菜叶绿休偶联因子的光合磷酸化功能影响不明显,对游离ＣＦ_１的Ｃａ~（２＋）－ＡＴＰ酶活力也无明显影响,但却能明显地促进它的Ｍｇ~（２＋－）ＡＴＰ酶活力。     

低温,高pH胁迫对水稻幼苗根系质膜,液泡膜ATP酶活性的影响

以耐冷性不同的两个水稻品种为材料,比较研究了幼苗根系质膜、液泡膜ＡＴＰ酶对低温（８℃）及高ｐＨ（８．０）胁迫的反应。结果表明：水稻根细胞质膜和液泡膜上均存在Ｃａ＾２＋－ＡＴＰ酶,但活性远低于Ｈ＾＋－ＡＴＰ酶。耐冷品种武育粳３号经低温（８℃）处理２ｄ,根系质膜和液泡膜Ｈ＾２＋－ＡＴＰ酶、Ｃａ＾２＋－ＡＴＰ酶海性均明显升高,至冷处理１２ｄ,Ｈ＾＋－ＡＴＰ酶、Ｃａ＾２＋－ＡＴＰ酶活性有所下降,但仍与对照     

铝和铝＋钙对小麦幼苗根尖质膜,液泡膜微囊ATP酶和膜流动性？…

研究了铝和铝＋＿钙对小麦功苗根尖质膜、液泡膜微囊Ｈ＾＋－ＡＴＰ酶、Ｃａ＾２＋－ＡＴＰ酶、Ｍｇ＾２＋－ＡＴＰ酶活性及共动力学参数和膜流动性的影响。在质膜和液泡膜微囊制剂中加入１．０ｍｍｏｌ／Ｌ的ＡＩ＾３＋（ＡＩＣＩ３）时,Ｈ＾２＋－ＡＴＰ囊制剂中加入１．０ｍｍｏｌ／Ｌ的ＡＩ＾３＋（ＡＩＣＩ３）时,Ｈ＾＋－ＡＴＰ酶、Ｃａ＾２＋－ＡＴＰ酶、Ｍｇ＾２＋－ＡＴＰ酶活笥和酶促反应的Ｖｍａｘ及膜流动性下降,而酶     

神经节苷脂GM_3对肌质网Ca~（2＋）－ATP酶活力的调节

研究了神经节苷脂ＧＭ_３参入肌质网膜后Ｃａ~（２＋）－ＡＴＰ酶活力的变化,结果表明：ＧＭ_３参入肌质网膜后,对肌质网Ｃａ~（２＋）ＡＴＰ酶活性（ＡＴＰ水解活力与转运活力）有明显的激活作用．当参入的ＧＭ_３浓度为８μｍｏｌ／Ｌ、参入时间为１２０ｍｉｎ、温度为３０℃时,对Ｃａ~（２＋）－ＡＴＰ酶的激活作用最大．     

高血压大鼠红细胞膜Ca~（2＋），Mg~（2＋）─ATP酶对Ca~（2＋）反应的变化及Mg~（2＋）的作用

本实验观察了正常及高血压大鼠红细胞膜Ｃａ２＋,Ｍｇ２＋－ＡＴＰ酶对不同浓度Ｃａ２＋及Ｍｇ２＋的反应。结果表明：（１）在自发性高血压大鼠（ＳＨＲ）,此酶最适反应的Ｃａ２＋浓度为１０－６ｍｏｌ／Ｌ;ＷＫＹ大鼠为１０－４ｍｏｌ／Ｌ;两肾一环型肾性高血压大鼠（ＲＨＲ）为１０－７ｍｏｌ／Ｌ,Ｗｉｓｔａｒ大鼠为１０－４ｍｏｌ／Ｌ,Ｃａ２＋高于以上各相应浓度时该酶活性受到抑制;（２）作为该酶激动剂的Ｍｇ２＋有其最适激活浓度,在ＷＫＹ大鼠、ＲＨＲ及Ｗｉｓｔａｒ大鼠均为４．５ｍｏｌ／Ｌ;（３）高浓度Ｍｇ２＋（３６．０ｍｏｌ／Ｌ）可以逆转高浓度Ｃａ２＋对该酶的抑制作用。以上结果表明,底物Ｃａ２＋浓度的变化对Ｃａ２＋,Ｍｇ２＋－ＡＴＰ酶的催化活性影响极大,该酶活性的促发及维持必须有适宜浓度的Ｍｇ２＋。高血压时此酶对Ｃａ２＋的敏感性增高,且Ｍｇ２＋对酶保护作用更为明显。本结果提示,胞内高浓度Ｃａ２＋不仅是高血压发生的原因之一,并可能与其发展及恶化有关。     

神经革苷脂GM3对肌质网Ca^2＋—ATP酶活力的调节

研究了神经节苷脂ＧＭ３参入肌质网膜后Ｃａ＾２＋－ＡＴＰ酶活力的变化。结果表明：ＧＭ３参入肌质网膜后,对肌质网Ｃａ＾２＋－ＡＴＰ酶活性（ＡＴＰ水解活力与转运活力）有明显的激活作用。当参入的ＧＭ３浓度为８μｍｏｌ／Ｌ、参入时间为１２０ｍｉｎ、温度为３０℃时,对Ｃａ＾２＋－ＡＴＰ酶的激活作用最大。     

抗寒剂CR—4对冬小麦幼苗质膜钙泵（Ca^2＋—ATPase）的稳定作用

通过磷酸铈沉淀的细胞化学观察揭示,常温下生长的冬小麦幼苗的Ｃａ２＋ＡＴＰ酶活性主要定位在质膜上,同时,水浸种和抗寒剂浸种的小麦质膜Ｃａ２＋ＡＴＰ酶活性没有差异。然而,小麦幼苗经－７℃冰冻处理１２小时和２４小时后,则表现明显的区别：水浸种的小麦幼苗质膜Ｃａ２＋ＡＴＰ酶活性明显下降,直至完全失活,细胞的精细结构也同时被破坏;而经抗寒剂浸种的小麦幼苗质膜Ｃａ２＋ＡＴＰ酶仍维持较高的活性,细胞结构也保持完整,显示抗寒剂对质膜Ｃａ２＋ＡＴＰａｓｅ酶起着明显的稳定作用。     

钙素和水分亏缺对黄瓜叶片细胞质膜透性的影响

用控制溶液的钙量[加或不加Ca(NO_3)_2]和渗透势(加聚乙二醇6000,202 g/L)的方法,研究了钙素和水分亏缺对黄瓜叶片细胞质膜透性的影响。结果表明:在渗透胁迫下,正常供钙的黄瓜叶片相对含水量(RWC)和膜透性变化较小、MDA增加不显著、SOD活性无明显改变;缺钙植株叶片的RWC随渗透胁迫处理线性下降,膜透性显著增大、MDA含量迅速提高、SOD活性也升高。在正常水分供应下,与供钙植株相比,缺钙植株SOD活性和MDA含量均较高,但RWC和膜透性无差异。在水分胁迫下,缺钙植株MDA和质膜透性与ΔRWC以及MDA与质膜透性之间均呈正相关。这些结果表明在水分胁迫下,缺钙处理叶片保水能力降低,使受害加重;同时,细胞质膜的稳定性降低。膜透性改变可能与在水分胁迫下体内的膜脂过氧化反应密切相关,即缺钙加速了膜脂过氧化反应,从而损害了质膜结构。     

烟草叶片发育过程中光合功能衰退与H_2O_2积累的关系

以烟草(NicotianatabacumL.cvNC89)为材料,研究了叶片发育过程中H2O2积累与叶绿体光合功能衰退、抗坏血酸-谷胱甘肽(AsA-GSH)循环的关联。结果表明,光合功能衰退过程中,各光合参数均表现为先缓慢后快速的下降趋势,核酮糖-1,5-二磷酸羧化酶(RuBPCase)活性下降较电子传递活性下降迅速,H2O2含量与叶绿素含量、光合速率、RuBPCase活性、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性显著负相关。H2O2的定位染色也证实光合功能衰退与H2O2积累密切相关。APX和GR在光合功能可逆衰退阶段维持较高水平,不可逆衰退阶段下降稍快。烟草叶片光合功能衰退快于AsA-GSH循环运转的下调。     

烟草叶片发育过程中光合功能衰退与H2O2积累的关系

以烟草（Nicotiana tabacum L．cv NC89）为材料,研究了叶片发育过程中H2O2积累与叶绿体光合功能衰退、抗坏血酸-谷胱甘肽（AsA—GSH）循环的关联。结果表明,光合功能衰退过程中,各光合参数均表现为先缓慢后快速的下降趋势,核酮糖-1,5-二磷酸羧化酶（RuBPCase）活性下降较电子传递活性下降迅速,H2O2含量与叶绿素含量、光合速率、RuBPCase活性、抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）活性显著负相关。H2O2的定位染色也证实光合功能衰退与H2O2积累密切相关。APX和GR在光合功能可逆衰退阶段维持较高水平,不可逆衰退阶段下降稍快。烟草叶片光合功能衰退快于AsA—GSH循环运转的下调。     

转Bt基因棉花杀虫晶体蛋白的表达及光合特性的研究

转Bt基因棉花(GK、ZK)及非Bt基因棉花(CZ)杀虫晶体蛋白表达及光合特性的研究表明,杀虫晶体蛋白在转Bt基因棉花GK与ZK中的表达总量及在各器官中的分配均有所不同．转Bt基因棉花叶片的净光合速率的光响应与常规棉有所不同．转Bt基因棉花GK与ZK叶片的叶绿素含量、净光合速率、蒸腾速率的日变化有明显的不同,而胞间二氧化碳浓度、气孔限制值、叶温的日变化趋势则基本一致．胞间二氧化碳浓度的日平均值在两转Bt基因棉花间的差异达显著水平,而其它各指标在不同处理间的差异均未达显著．     

大豆叶片发育中光合、结构及其与3种酶活性的关系

大豆叶片的光合速率、希尔反应活性、叶绿素含量、类囊体垛迭程度都随叶片扩展而增加、随老化而下降;希尔反应在老化时下降最早.次之为叶绿素含量和光合速率;类囊体膜随老化而解体.淀粉粒也减少以至消失,而脂质体球逐渐增加最后涨破叶绿体,叶片透性也增加.过氧化氢酶(CAT)活性随老化下降,超氧化物歧化酶(SOD)活性在发育旱期和老化后期较高.过氧化物酶(POD)活性则随发育及老化而不断升高.讨论了光合活性与结构及三个酶活性之间的关系.     

施氮量对小麦叶片硝酸还原酶活性、一氧化氮含量和气体交换的影响

研究了不同施氮量对冬小麦分蘖到抽穗期叶片硝酸还原酶(NR)活性、一氧化氮(NO)含量、气体交换参数和籽粒产量的影响.结果表明:叶片光合速率（P_n）、蒸腾速率（T_r）、瞬时水分利用效率（IWUE）和产量均随施氮量的增加呈先升高后降低的趋势,在180 kg·hm^-2氮处理时达到最高.随施氮量的增加,叶片NR活性提高; 在分蘖期和拔节期,叶片NR活性与NO含量呈显著线性相关（R²≥0.68,n=15）,NO含量和气孔导度（G_s）呈显著正二次相关（R²≥0.43,n=15）;低氮处理下,NR活性较低使叶片NO含量维持在较低水平,促进气孔开放,高氮处理下,NR活性较高使叶片NO含量增加,诱导气孔关闭;在抽穗期叶片NR活性和NO含量无显著相关关系,虽然NO含量和G_s也呈显著正二次相关（R²≥0.36,n=15）,但不能通过施氮提高NR活性来影响叶片NO含量,进而调节叶片气孔行为.合理施氮使小麦叶片NO含量维持在较低水平,可提高叶片G_s、T_r和IWUE,增强作物抗旱能力,促进光合作用,提高小麦产量.     

Regulation by kinetin and abcisic acid of correlative senescence in relation to grain maturation,source-sink relationship and yield of rice (Oryza sativa L.)

When kinetin was applied to the source organ (flag leaf) of rice (Oryza sativa L. cv. Ratna), foliar senescence was delayed and grain yield per plant (as evidenced by grain weight, grain/straw weight ratio and 1,000 grain growth) was increased through the increase of sink activity (increase in dry weight of the grains/plant), duration of sink capacity as well as photosynthetic ability of the glumes (as determined by the chlorophyll content of the glumes of the developing grains). However, application of kinetin to the sink organs (fruits), promoted senescence of the source but increased the yield by increasing the sink capacity and 1,000 grain growth mostly at the earlier stage of reproductive development. Lower sterility percentage was associated with higher grain yield of the plant by kinetin treatments. ABA applied either to the source or the sink promoted leaf senescence and reduced the grain yield by reducing the sink activity, harvest index, sink capacity duration and increasing the sterility percentage. Thousand grain dry weight at harvest did not vary significantly amongst the treatments. It was concluded that nutrient drainage was associated with the correlative influence of fruit on the monocarpic senescence of rice plant and that a competetion for differential allocation of cytokinin and ABA in the source and sink organs initiates this senescence syndrome.     

铜胁迫对狭叶香蒲生长及生理特性的影响

采用水培法,研究不同浓度Cu~(2+)胁迫对狭叶香蒲生长及生理特性的影响。结果表明:狭叶香蒲叶宽、株高的增长量及整株干物质累积量在较低浓度Cu~(2+)处理时均未受影响,此后随Cu~(2+)浓度升高显著下降。Cu~(2+)浓度为o～30 mg·L~(-1)时,叶绿素含量显著上升,此后随Cu~(2+)浓度增加其含量显著下降。在Cu~(2+)浓度0～5 mg·L~(-1)范围内根系活力显著上升,此后随Cu~(2+)浓度升高则大幅下降。根系和叶片SOD、POD、CAT、活性随Cu~(2+)浓度增加均呈先显著升高后显著降低的趋势,根系SOD、POD活性在30 mg·L~(-1)时出现最大值,叶片SOD、POD活性在55 mg·L~(-1)时出现最大值,根系和叶片CAT活性均在80 mg·L~(-1)时出现最大值;同一Cu~(2+)浓度下,根系SOD、POD、CAT活性明显高于叶片,说明根系比叶片对Cu~(2+)胁迫反应更敏感。从根系和叶片SOD/POD、SOD/CAT的比值变化上看出,在Cu~(2+)为1 mg·L~(-1)和5 mg·L~(-1)时起主要保护作用的酶是SOD、POD,后来CAT起到主要作用。MDA含量自Cu~(2+)浓度为30 mg·L~(-1)时开始持续上升。说明在Cu~(2+)为30～55 mg·L~(-1)时狭叶香蒲表现为积极的生理响应。     

Overexpression of Superoxide Dismutase Protects Plants from Oxidative Stress (Induction of Ascorbate Peroxidase in Superoxide Dismutase-Overexpressing Plants)

Photosynthesis of leaf discs from transgenic tobacco plants (Nicotiana tabacum) that express a chimeric gene that encodes chloroplast-localized Cu/Zn superoxide dismutase (SOD+) was protected from oxidative stress caused by exposure to high light intensity and low temperature. Under the same conditions, leaf discs of plants that did not express the pea SOD isoform (SOD-) had substantially lower photosynthetic rates. Young plants of both genotypes were more sensitive to oxidative stress than mature plants, but SOD+ plants retained higher photosynthetic rates than SOD- plants at all developmental stages tested. Not surprisingly, SOD+ plants had approximately 3-fold higher SOD specific activity than SOD- plants. However, SOD+ plants also exhibited a 3- to 4-fold increase in ascorbate peroxidase (APX) specific activity and had a corresponding increase in levels of APX mRNA. Dehydroascorbate reductase and glutathione reductase specific activities were the same in both SOD+ and SOD- plants. These results indicate that transgenic tobacco plants that overexpress pea Cu/Zn SOD II can compensate for the increased levels of SOD with increased expression of the H2O2-scavenging enzyme APX. Therefore, the enhancement of the active oxygen-scavenging system that leads to increased oxidative stress protection in SOD+ plants could result not only from increased SOD levels but from the combined increases in SOD and APX activity.     

Atmospheric CO2 enrichment alters energy assimilation, investment and allocation in Xanthium strumarium

Energy-use efficiency and energy assimilation, investment and allocation patterns are likely to influence plant growth responses to increasing atmospheric CO2 concentration ([CO2]). Here, we describe the influence of elevated [CO2] on energetic properties as a mechanism of growth responses in Xanthium strumarium. Individuals of X. strumarium were grown at ambient or elevated [CO2] and harvested. Total biomass and energetic construction costs (CC) of leaves, stems, roots and fruits and percentage of total biomass and energy allocated to these components were determined. Photosynthetic energy-use efficiency (PEUE) was calculated as the ratio of total energy gained via photosynthetic activity (Atotal) to leaf CC. Elevated [CO2] increased leaf Atotal, but decreased CC per unit mass of leaves and roots. Consequently, X. strumarium individuals produced more leaf and root biomass at elevated [CO2] without increasing total energy investment in these structures (CCtotal). Whole-plant biomass was associated positively with PEUE. Whole-plant construction required 16.1% less energy than modeled whole-plant energy investment had CC not responded to increased [CO2]. As a physiological mechanism affecting growth, altered energetic properties could positively influence productivity of X. strumarium, and potentially other species, at elevated [CO2].