【作者】 梁芳；

【导师】 郑成淑；

【作者基本信息】 山东农业大学 ， 园林植物与观赏园艺， 2009， 硕士

【摘要】 本试验以切花菊品种‘神马’(Dendranthema grandiflora‘Jinba’)为试材,分别在偏低温弱光(16℃/12℃,PFD100μmol·m-2·s-1)和临界低温弱光(12℃/ 8℃,PFD60μmol·m-2·s-1)下胁迫11 d后转入正常条件CK(22℃/18℃, PFD450μmol·m-2·s-1)恢复11d,研究了菊花对低温弱光胁迫的响应机理,并在低温弱光胁迫下,研究了乙酰水杨酸(ASA)和Ca2+处理对菊花光合机构及活性氧清除酶系统的影响,探讨了ASA和Ca2+处理对菊花低温弱光胁迫下缓解效应的可能的生理机制。主要研究结果如下:1.菊花对低温弱光胁迫的响应机理(1)偏低温弱光处理使菊花植株明显徒长,而临界低温弱光处理则导致菊花植株生长受到抑制;偏低温弱光处理有利于地上部的生长,而临界低温弱光处理则抑制了地上部的生长;两处理均抑制了菊花的花芽分化,且临界低温弱光处理的抑制作用更显著。胁迫解除后,偏低温弱光处理植株可恢复至正常生长,而临界低温弱光处理植株恢复缓慢,说明已对植株生长造成一定的伤害。(2)低温弱光处理导致菊花叶片的净光合速率(Pn)与气孔限制值(Ls)下降,而胞间浓度CO2(Ci)上升。引起Pn下降的主要原因是非气孔因素。偏低温弱光胁迫对菊花叶片的暗适应下最大光化学效率(Fv/Fm)和初始荧光(Fo)并无影响,光适应下最大光化学效率(Fv’/Fm’)处理前期略有下降,后期则有所回升,而临界低温弱光处理的Fo明显升高,Fv/Fm和Fv’/Fm’显著降低。PSⅡ光合电子传递量子效率(ΦPSⅡ)、光化学猝灭系数(qP)和电子传递速率(ETR)均随着低温弱光胁迫程度的增加和时间的延长而降低;偏低温弱光处理植株在解除胁迫后能迅速恢复到对照水平,而临界低温弱光处理植株回升速度较慢;同时,吸收光强分配于光化学反应的部分(Prate)减少,而天线热耗散(Drate)和反应中心的能量耗散(Ex)比例上升,但天线热耗散为主要的过剩光能分配途径。低温弱光处理使菊花叶片叶绿素a(Chla)含量、叶绿素b(Chlb)含量、叶绿素(a+b)[Chl(a+b)]含量、叶绿素(a/b)[Chl(a/b)]以及类胡萝卜素(Car)含量都降低。叶绿素、类胡萝卜素含量均在低温弱光胁迫下逐渐降低,是光合速率降低的主要原因之一。从整体看,临界低温弱光处理使上述参数变化的程度要比偏低温弱光处理更显著。(3)偏低温弱光处理使SOD活性在胁迫1～11d中持续上升,而临界低温弱光处理使SOD活性在前期(1～5d)上升,后期(5～11d)下降。随着低温弱光胁迫程度的增加和时间的延长,两处理均使菊花叶片中POD活性提高,但CAT活性下降,膜脂过氧化逐渐加剧,丙二醛(MDA)大量积累,相对电导率(REC)逐渐增加,膜透性增大。临界低温弱光处理比偏低温弱光处理对植株的影响更为显著。各指标在恢复期内均具有不同程度的缓解。(4)可溶性糖含量随低温弱光胁迫程度的增加和时间的延长而持续增加。偏低温弱光处理使可溶性蛋白和脯氨酸含量在胁迫1～11d中持续上升,而临界低温弱光处理使可溶性蛋白和脯氨酸含量都在前期(1～5d)上升,后期(5～11d)下降。各指标在恢复期内均具有不同程度的缓解。2. ASA和Ca2+处理对低温弱光胁迫下菊花的缓解效应机理低温弱光胁迫下,与对照相比,ASA和Ca2+处理抑制了净光合速率(Pn)、表观量子效率(AQY)、羧化效率(CE)、暗适应下最大光化学效率(Fv/Fm)以及实际光化学效率(ΦPSⅡ)和光化学猝灭系数(qP)的大幅度降低,而且明显提高了总叶绿素含量,相对提高了叶绿体数和淀粉粒数,并使菊花叶片细胞体积增大。表明ASA和Ca2+处理可有效提高低温弱光胁迫下菊花叶片的光合性能,因而提高了对低温弱光的耐性;低温弱光胁迫下,与对照相比,ASA和Ca2+处理的菊花叶片REC及膜透性伤害率显著下降,并提高了SOD、POD和CAT活性。说明ASA和Ca2+处理对低温弱光胁迫条件下菊花叶片保护酶活性具有正调控作用,这种正调控作用可能对低温弱光条件下菊花叶片的光合系统起到保护作用。综合作用效果表明,ASA与Ca2+复配处理优于ASA或Ca2+单一处理。更多还原

【Abstract】 The plants of cut flower chrysanthemum cv.‘Shenma’plants were selected as material to be treated with the combination of lower temperature and poor light (16℃/12℃, PFD100μmol·m-2·s-1), critical temperature and poor light (12℃/8℃, PFD60μmol·m-2·s-1) stress for 11 days and then transferred to normal conditions of CK (22℃/ 18℃, PFD450μmol·m-2·s-1) for 11 days, to study the mechanism of responsing to stress of low temperature and poor light in chrysanthemum. And the effects of acetylsalicylic acid (ASA) and Ca2+ treatments on its photosynthetic system and antioxidant enzyme activities under the stress of low temperature and poor light were investigated, and the possible physiological mechanisms of ASA and Ca2+ was discussed. The results showed as follows:1. Studies on Mechanism of responsing to stress of low temperature and poor light in chrysanthemum(1) The stress of lower temperature and poor light induced excessive vegetative growth but the stress of critical temperature and poor light restrained the growth of plant. The growth of shoots of chrysanthemum well under the stress conditions of lower temperature and poor light, but its were restrained under the stress conditions of critical temperature and poor light. The two treatments restrained flower bud differentiation of chrysanthemum, which was more significant under the stress of critical temperature and poor light compared to the stress of lower temperature and poor light.(2) The results showed that net photosynthetic rate (Pn) and stomatal limitation value (Ls) decreased, however intercellular CO2 concentration (Ci) increased.The cause of reduction of Pn in chrysanthemum leaves under the stress of low temperature and poor light might be mainly non-stomata limitation.The stress of combination of poor light and lower temperature did not affect maximal photochemical efficiency of PSⅡin the dark (Fv/ Fm) and initial fluorescence (Fo), and led to a little decrease during the early period of stress and recover slowly during the later period of stress in maximal photochemical efficiency of PSⅡin the light (Fv′/Fm′); But Fo and Fv/Fm increased as well as Fv′/Fm′decreased evidently under the stress of critical temperature and poor light;ΦPSⅡ, qP and Fv’/Fm’ decreased with stress degree increasing and time prolonging of low temperature and poor light, these parameters rapidly arose to a value similar to control for the treatment of poor light and low temperature, but recovered slowly for the stress of critical temperature and poor light after being released from the stress; At the same time, Prate decreased, but Drate and Ex increased under the low temperature and poor light. Drate was the main pathway of superfluous light allocation.Chla content, Chlb content, Chl (a+b) content, Chl (a/b) and Car content all reduced after treatment for 11 days. Decrease of contents of chlorophyll and carotenoid under the stress of low temperature and poor light maybe is one mainly cause resulting in the reducing of Pn.All in all, the changes of the above parameters under the stress of critical temperature and poor light were more significant than those under the stress of lower temperature and poor light.(3) SOD activities continually increased during the stress for days under stress of lower temperature and poor light, but SOD activities increased in the earlyer stages (1～5d) and decreased in the later stages (5～11d). Membrane permeabilities,POD activities increased, while CAT activities decreased and membrane lipid peroxidization pricked up, following MDA accumulation and cell leakage increasing in chrysanthemum leaves with stress degree increasing and time prolonging. The stress of lower temperature and poor light had opposite effects than the stress of critical temperature and poor light. Each index had reversed by different degree.(4) Contents of soluble sugar appeared durative increase with stress degree increasing and time prolonging. Soluble protein and proline increased during the stress for days under stress of lower temperature and poor light, which increased in the earlyer stages (1～5d) and decreased in the later stages (5～11d). Each index had reversed by different degree.2. Studies on mechanism of alleviatory effect of ASA and Ca2+ under stress of low temperature and poor light in chrysanthemum Under the stress of low temperature and poor light, combination application of ASA and CaCl2 addition greatly inhibited the netphotosynthesis rate (Pn) , carboxylation efficiency (CE), apparent quantum yield (AQY), maximal photochemical efficiency of PSⅡin the dark (Fv/Fm), quantum yield of PSⅡe lectron transport (ΦPSⅡ) and photochemical quenching (qP) compared with those of controls, single application of ASA or CaCl2. The combination application of ASA and CaCl2 obviously improved the chorophyll content, relatively improved the number and size of chloroplasts and starch grainins in the leaves of chrysanthemum under the stress of low temperature and poor light. The results suggested that ASA and CaCl2 could regulate the leaf photosynthetic functions in the leaves of chrysanthemum, and enhance the resistance against to the low temperature and light intensity. ASA and CaCl2 could reduce relative conductance rate and injury rate of leaves of chrysanthemum and increase the activities of SOD, POD and CAT and the contents of soluble protein compared with those of the controls, indicating that ASA and CaCl2 had positive regulation effects on the defense enzyme activities in chrysanthemum leaves, which could protect the photosynthetic system of the leaves of chrysanthemum under the stress of low temperature and poor light to a certain degree. Induced resistance effects of ASA and CaCl2 mixture was better than single application of ASA or CaCl2.更多还原