高温胁迫对茶树叶片光合系统的影响

摘要

以龙井43为材料，高温（43℃）处理48 h后，分别用调制荧光成像系统和双通道荧光仪分析其受胁迫的状态和光合系统的受损情况。结果表明，受到高温胁迫后：茶树会表现出一系列的热害症状；茶树叶片的光合速率持续下降，Rubisco最大羧化速率（Vc,max）以及RuBP的最大再生速率（Jmax）显著降低；Fv/Fm、Y(II)和Y(I)迅速降低，Y(NO)和 Y(NA)上升，说明光系统 II 和光系统 I 的结构在高温胁迫下受到了伤害；茶树的ΦPSⅡ、ETR(II)和 ETR(I)均显著下降，表明电子传递受到严重破坏；光系统 I 对高温胁迫的耐受性较高，抗强光损伤能力在高温胁迫下变强，而光系统II易受到高温伤害，抗强光损伤能力在高温胁迫下变弱。%Abastract:To study the effects of heat stress on the photosynthesis systemofteaplant(Camellia sinensisL.), seedlings of‘Longjing 43’cultivar were challenged with high temperature (43℃) for 48 h followed by observation of photosynthetic apparatus by using Imaging Fluorescence system and Dual-PAM. Results obtainedwereas follows:Heat stress caused obvious alterations in the leaf phenotype.Net photosynthetic rate declined gradually following heat stress which was accompanied with significant decreases in the maximum carboxylation rate of Rubisco and the maximum RuBP regeneration rate.Heat stress decreased Fv/Fm, Y(I) and Y (II) rapidly, but increased Y(NO) and Y (NA), indicating thatboth photosystemIIand photosystemIwere damaged by heat stress.ΦPSⅡ,ETR(II) and ETR(I) were also decreased significantly by heat stress, suggesting that heat stress possibly blocked the electron transduction, in tea leaves, photosystemIwas more tolerant to heat stress, while photosystemIIwas relatively sensitive.