水稻叶片的衰老与超氧物歧化酶活性及脂质过氧化作用的关系

研究了从抽穗开花到籽粒成熟过程中,水稻植株顶部三片叶子的超氧物歧化酶(SOD),脂质过氧化产物丙二醛(MDA)含量及二磷酸核酮糖羧化酶活性的变化。实验结果表明:叶片的衰老伴随着 SOD 活性、RuBP 羧化酶活性及叶绿素含量的降低、丙二醛含量显著增高。分离了三个 SOD 的同工酶,证明为 Cu—Zn SOD。观察了 SOD 同工酶在叶片老化及酶液存放不同时间中的变化。讨论了叶片衰老过程中氧自由基对酶及质膜的损伤影响。     

杂交稻及其三系叶片衰老过程中SOD、CAT活性和MDA含量的变化

对杂交水稻及其三系主茎第11叶叶片自然衰老过程中超氧物歧化酶(SOD)、过氧化氢酶(CAT)和丙二醛(MDA)含量的变化进行了研究,结果表明:叶片衰老过程中,SOD和CAT活性下降,MDA的含量增加,可作为衰老特征的叶绿素和可溶性蛋白质含量明显下降;SOD的活性和MDA的含量变化相对应;CAT活性大幅度下降与SOD之间的不平衡,致使O_2~-代谢中间产物累积而引起膜的损伤。不育系的衰老进程比杂交水稻、恢复系和保持系慢,其SOD和CAT活性明显高于其它三者,可能是不育系不易早衰的原因之一。     

The Effect of Light and Hormones on Leaf Senescence

With wheat leaves as material, the changes of superoxide dismutase (SOD), lipid peroxi-dation and membrane permeability during leaf senescence in light or dark, and treated withphytohormones (KT or ABA) have been studied. The changes of chlorophyll content, lipidperoxidation and fine structure of spinach chloroplasts senescing in light or dark have alsobeen studied. When leaves senesce in light, the activity of SOD increased at first then decreased. The increase of SOD activity was able to result from the synthesis of new protein. Lightwas found to delay the leaf senescence obviously but also accelerate leaf senescence by causinglipid peroxidation when prolonged the illumination time. The delay or acceleration of leafsenescence by exogenous hormones were observed, it may be due to the control of lipid peroxi-dation by adjusting the activity of SOD. O2-participated the chlorophyll decomposition andlipid peroxidation during chloroplasts senesce in light. A favourable role of light in mainta-lng the fine structure of isolated chloroplasts was clear.     

棉花叶片衰老过程中激素和膜脂过氧化的关系

以陆地棉品种辽棉9号的去根幼苗为材料,对其进行暗诱导衰老培养.在培养液中分别加入6-BA、ABA、GSH、H2O2、CaCl2、A23187 和A23187 CaCl2,测定在不同培养条件下棉花去根幼苗叶片内源激素、SOD酶活性和MDA含量的变化.结果表明:棉花叶片衰老表现为细胞分裂素含量的下降和ABA含量的上升.6-BA、GSH和钙离子均延缓叶片的衰老,ABA和H2O2促进叶片的衰老.     

Leaf Senescence: Correlated with Increased Levels of Membrane Permeability and Lipid Peroxidation, and Decreased Levels of Superoxide Dismutase and Catalase

The changes in membrane permeability (soluble leakage), lipidperoxidation, and activities of superoxide dismutase (SOD) andcatalase have been studied during in situ senescence of leavesof Nicotiana tabacum L., cv. Wisconsin 38. After full leaf expansionwas reached there was a rapid, almost linear increase in therate of ⁸⁶Rb leakage from the preloaded leaf discs, with leafage. Parallel with this increase in membrane permeability wasa cumulative increase in the level of lipid peroxidation. Atthe same leaf age there were changes in the activities of SODand catalase. SOD activity decreased on the basis of fresh weightbut did not change when measured on the basis of protein contentprobably due to relative stability of SOD during the senescence-associatedgeneral decline in protein content. Catalase activity firstincreased parallel with the chlorophyll content of the leafand then, after full leaf expansion, declined on the basis ofboth fresh weight and protein content. These changes in membranepermeability, lipid peroxidation, and the enzyme activitiescoincide in leaf age with the decline in protein and chlorophyllcontents and in chlorophyll a: b ratio. When the senescenceof the bottom-most leaves was reversed by removing the stemfrom immediately above them, the senescence-associated changesin protein and chlorophyll contents, lipid peroxidation, andthe enzyme activities were also reversed. It is suggested thatleaf senescence may be a consequence of cumulative membranedeterioration due to increasing level of lipid peroxidationprobably controlled by, among other factors, the activitiesof SOD and catalase.     

萝卜离体子叶衰老与膜脂过氧化的关系

萝卜离体子叶在光下或暗中衰老及激素调节衰老过程中,作为叶片衰老指标的叶绿素和蛋白质含量的降低,发生在MDA含量增高之前,更早于SOD活性的下降。表明由SOD活性降低所导致的膜脂过氧化的增强,并非衰老的原初反应,而是叶片衰老到一定程度的生理变化。因此,至少在萝卜离体子叶上,不能将其衰老的启动归因于受SOD控制的膜脂过氧化作用导致的膜累积性质变。     

Retardation of Leaf Senescence by Triadimefon Treatment in Mung Bean Seedling

Treatment of triadimefon on detached leaves of mung bean (Phaseolus radiatus L. ) seedlings increased the levels of chlorophyll and soluble proteins. Declined activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate-peroxidase (AsA-POD) and contents of ascorbate (ASA) and glutathione (GSH) were observed during the senescence of detached young leaves. Triadimefon at concentration of 20 mg/L promoted the activities of POD, AsA-POD and levels of AsA and GSH, but had no effect on the activities of SOD and CAT. On the other hand, the levels of malondialdehyde (MDA) were increased and the increase of which was markedly negative correlated with the activities of POD, AsA-POD and with the contents of AsA and GSH during the senescence of leaves. MDA contents were decreased by triadimefon treatment. These resuits suggested that triadimefon retarded the senescence of leaves in mung bean seedlings in terms of enhancing the protective ability of plant tissues against membrane lipid peroxidation.     

Chloroplast pigments,proteins, lipid peroxidation and activities of antioxidative enzymes during maturation and senescence of leaves and reproductive organs of Cajanus cajan L.

A comparative investigation was undertaken with pigeon pea leaves and attached flower buds/flowers/pods during their developmental stages including senescence in a natural system in experimental plots. Alterations in chloroplast pigments, total soluble proteins, lipid peroxidation, malondialdehyde (MDA) content and activities of guaiacol peroxidase (POD, EC 1.11.1.7) and superoxide dismutase (SOD, EC 1.15.1.1) were studied at 5-day interval from initial to 40-day stage. Chloroplast pigments and proteins of leaves increased upto 15 and 20-day stages respectively followed by a steady decline. Reproductive parts, however, exhibited rise in chloroplast pigments upto 25-day and protein till last stage as developing pods gain the amount from the senescing leaves which are nearest to them. Senescing leaves show very high POD activity than the developing and senescing pods and POD appears to be associated with chlorophyll degradation. Considerably higher activity and amount of LOX and MDA respectively have been noticed in senescing leaves than in flowers and pods. Increase in SOD activity during early stage of leaf growth and maturation indicates protective role that declined at senescent stages. Pods are unique in having very high SOD activity, only last stage of senescence does show a decline.     

氮素对不同品种烤烟叶片衰老、光合特性及产量和品质的影响

以豫烟5号、豫烟7号和NC89为材料,研究氮素对不同品种烤烟叶片衰老、光合特性及产量和品质的影响.结果表明：增施氮素可显著增强烤烟叶片超氧化物歧化酶(SOD)活性,降低丙二醛(MDA)含量,提高叶绿素含量,增强光合性能,从而延缓烤烟叶片衰老.与豫烟5号和NC89相比,豫烟7号叶片叶绿素含量较低,光合性能较弱,SOD活性低,MDA含量高,叶片衰老较快.与60和75 kg·hm^-2施N处理相比,45 kg·hm^-2 施N处理的烟叶均价、产值、上等烟比例均最高,且化学品质指标较好,符合优质烟叶要求.表明不同品种烤烟衰老生理特性有明显差异;氮素营养对烤烟叶片衰老、产量和品质有明显的调节作用;适量施氮可提高烟叶品质,获得较高的经济效益.     

Relation between Nitrogen and Ribulose-1,5-bisphosphate Carboxylase in Rice Leaves from Emergence through Senescence

The relation between N content and ribulose-l,5-bisphosphate(RuBP) carboxylase protein was examined in the 12th leaf bladeof rice. Plants were grown under different amounts of N afterthe emergence of the 12th leaf blade. RuBP carboxylase proteinincreased with leaf N during leaf expansion. The synthesis ofRuBP carboxylase predominated during this period, and changesin the amounts of carboxylase synthesized until leaf death paralleledchanges in the N influx to the leaves. When the carboxylasereached its maximum content, the proportion of RuBP carboxylaseto leaf N was 27 to 28% irrespective of N treatment. As theleaf senesced, however, this proportion differed significantlywith the treatment. It was higher in the N-deficient leaf thanin the N-sufficient leaf. This was due to different patternsof RuBP carboxylase degradation for the treatments during senescence.RuBP carboxylase was degraded actively during the early stageof senescence in the N-sufficient leaf, whereas its degradationproceeded almost constantly in the N-deficient leaf during senescence. (Received October 17, 1983; Accepted January 27, 1984)     

遮荫对半夏叶片光合色素与保护酶活性的影响

对半夏进行不同程度遮荫处理,研究了其生长过程中叶组织的光合色素含量、叶绿素a/b值、保护酶体系(SOD、POD、CAT)活性和丙二醛(MDA)含量的变化及其生理特性.结果表明:不同处理的半夏在生长过程中,光合色素的含量呈先升后降的趋势;与全光照相比,遮荫处理的叶绿素含量较高,叶绿素a/b值较低,类胡萝卜素含量在生长发育中早期较低而后期较高;SOD、POD、CAT活性呈由低到高再降低的趋势,MDA含量持续升高;遮荫处理的SOD、POD活性和MDA含量均低于全光照处理,CAT活性则表现为先高于后低于全光照处理.适度的遮荫可以提高半夏叶绿素的含量,降低膜系统受到的伤害,改善半夏的倒苗状况,为半夏叶片的生长提供较好的环境.     

外源抗坏血酸对臭氧胁迫下水稻叶片膜保护系统的影响

在田间原位条件下,运用OTCs（open top chamber）装置研究了外源抗坏血酸（exogenous ascorbate acid,ExAsA）对臭氧（O3）胁迫下水稻（Oryza Sativa L.）叶片膜保护系统的影响.研究发现,O3胁迫下的水稻叶片经过ExAsA处理后叶绿素a含量显著升高,而叶绿素b含量变化不明显;相对于对照,经ExAsA处理后的水稻叶片过氧化氢（H2O2）和丙二醛（MDA）含量及相对电导率（REC）均降低,超氧化物岐化酶（SOD）和抗坏血酸过氧化物酶（APX）活性明显提高,抗氧化剂类胡萝卜素（Carotene）含量升高.这表明,ExAsA改善了O3胁迫下水稻叶片的抗氧化系统功能,减少了叶片中活性氧（activity oxygen species,AOS）的积累,抑制了脂质过氧化（lipid peroxidation,LP）,延迟了O3对水稻叶片的老化作用,提高了水稻叶片对O3危害的抗性.     

Induction of new isoforms of superoxide dismutase and catalase enzymes in the flag leaf of wheat during monocarpic senescence.

Leaf senescence is a programmed cell death phenomenon and involves oxidative stress. Superoxide dismutase (SOD, EC 1.15.1.1) and catalase (CAT EC 1.11.1.6) activities were studied in the flag leaf of Triticum aestivum cv. Kundan at different stages of grain development. Both SOD and CAT activities showed a decline during monocarpic senescence. Three SOD isozymes were observed in the cytosol, of which one isozyme was observed in the chloroplasts as well. Mitochondria showed the presence of three low abundant SOD isoforms. Inhibitor studies revealed the cytosolic and chloroplastic isoforms to be Cu/Zn SODs. In mitochondria however, two isozymes were MnSOD and one of them appeared to be FeSOD. These isoforms present in the mitochondria increased in activity as senescence progressed. Three isoforms of CAT were observed in peroxisomes which responded differentially during monocarpic senescence. The changes in the kind and pattern of the antioxidant enzymes supported the ordered sequence of events during leaf senescence. This is the first report showing an increase in mitochondrial FeSOD activity during leaf senescence.     

银杏叶片衰老过程中光合生理特性及叶绿体超微结构的变化

选取自然条件下生长的雌雄银杏植株为实验材料,测定了银杏叶片在衰老过程中部分光合生理指标及叶绿体超微结构的变化。检测结果表明：银杏叶片在衰老过程中净光合速率、叶绿素含量均呈下降趋势,SOD、CAT、APX活性均先上升后下降,MDA含量则一直呈现上升趋势。叶片衰老过程中叶绿体类囊体膜片层逐渐松散,直至膜结构逐渐解体,叶绿体内油脂颗粒增大增多,最终解体。雌雄银杏植株在各项生理指标上差异不显著。     

大穗型水稻生育后期叶片和根系生理的特性

Ｇ Ｅ Ｒ１ 是从玉米 Ｄ Ｎ Ａ 导入水稻的后代变异材料中筛选出的大穗型高产变异系⒚对 Ｇ Ｅ Ｒ１ 生育后期叶片和根系生理特性的研究表明：与受体湘早籼 ８ 号和三系杂交稻汕优 ６３相比, Ｇ Ｅ Ｒ１ 的顶三叶叶绿素含量、蛋白质含量、光合速率、过氧化物酶和超氧化物歧化酶活性降幅小,丙二醛含量增幅小,叶片衰老得到延缓,生育后期根量和根系伤流量较大、发根力和根系 α萘胺氧化力较强⒚生育后期叶片和根系的延缓衰老使得叶片功能期长、光合产物供应充足,是实现大穗多穗条件下水稻高结实率和充实度好的主要内在原因⒚     

Pyrophosphatase, Peroxidase and Polyphenoloxidase Activities during Leaf Development and Senescence

Inorganic pyrophosphatase, peroxidase, and polyphenoloxidase activities were studied as the function of leaf insertion level in eight monocotyledonous and eight dicotyledonous species. Alkaline inorganic pyrophosphatase shows a declining activity toward the end of senescence whereas no regular drift in either peroxidase or polyphenoloxidase activities was noticed during senescence of attached leaves. In the primary leaves of rice, peroxidase and polyphenoloxidase activities were high in the senescent leaves and there exists a correlation between chlorophyll content and peroxidase activity though not with polyphenoloxidase activity. Upon detachment leaves exhibit increasing peroxidase and polyphenoloxidase activities with time. The distribution of the enzyme activities during senescence of attached leaves is suggested to be species-specific, and an increase in peroxidase and polyphenoloxidase activities cannot be taken as an indicator of leaf senescence.     

水稻抽穗后剑叶衰老过程中光合关键酶的基因表达

协优 930 8、培矮 6 4s/ 9311和汕优 6 3三个超级高产水稻品种抽穗后 ,剑叶中光合速率减小、叶绿素含量下降、SOD活力降低和MDA含量上升的幅度不同 ,显示它们开花结实过程中叶片衰老的速度不同 ,以汕优 6 3衰老最快 ,协优 930 8最慢 ,培矮 6 4s/ 9311居中。Northern杂交和免疫定量研究表明 ,汕优 6 3和培矮6 4s/ 9311剑叶rbcS(Rubisco小亚基基因 )和rca(Ru bisco活化酶基因 )mRNA的表达随抽穗后天数的增加而下降 ,而协优 930 8在抽穗后第 10天才开始下降 ;Rubisco和Rubisco活化酶蛋白含量的下降趋势与rbcS和rcamRNA的变化趋势相似。因此 ,水稻抽穗后剑叶衰老过程中光合能力的下降与光合关键酶基因(rbcS和rca)表达下降密切相关     

在光氧化条件下不同类型高产稻的叶绿素荧光特性和膜脂过氧化特点

用不同类型高产稻(Oryza sativa L.)粳稻9516、具有粳型成分的两系法亚种间杂交稻培矮64/E32、两优培九(培矮64/9311)和籼型杂交稻X07S/紫恢100、冈优881、汕优63为材料,研究了孕穗期叶片在光氧化条件下的叶绿素荧光特性和膜脂过氧化表现.光氧化处理后,与籼型杂交稻比较,粳稻和具有粳型组分的亚种间杂交稻的PSⅡ原初光化学效率(Fv/Fm)、PSⅡ的线性电子传递的量子效率(ΦPSⅡ)和光化学猝灭系数(qP)下降的较少;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)诱导的活性较高,活性氧 (O(-)/()2、H2O2)和丙二醛(MDA)的产生积累较少,叶绿素和蛋白质含量下降较少,表现出耐光氧化特性,这与在自然条件下生育后期叶绿素含量变化相一致.相关分析表明它们的耐光氧化特性与结实率密切相关,说明耐光氧化品种抗早衰,有利籽粒充实.这些结果启示我们:从超高产育种出发,兼顾杂种优势利用和抗早衰两方面考虑,在母本不育系中引入粳型成分是一个值得重视的育种策略.     

钙对杂交水稻叶片中活性氧防御酶的影响

钙能提高杂交水稻叶片的叶绿素和蛋白质含量,主要是由于钙能提高活性氧防御酶ＳＯＤ、ＰＯＤ、ＣＡＴ活性,降低ＭＤＡ含量和活性氧的伤害作用     

烯效唑干拌种对小麦叶片衰老期间有关酶活性的影响

研究不同浓度(0、10、20、40mg·kg-1)烯效唑干拌种对小麦品种川麦30不同叶序(3叶、7叶、旗叶)叶片衰老期间酶活性影响的结果表明,烯效唑干拌种后,不同叶序叶片超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性增强,衰老后期仍维持较高水平;而核糖核酸酶(RNase)活性水平及上升速率则受抑,叶片中丙二醛(MDA)积累量减少,可溶性蛋白质含量下降缓慢.