交替呼吸途径防御弱光干旱下辣椒叶片光抑制的作用研究

PROTECTIVE ROLES OF ALTERNATIVE OXIDASE PATHWAY TO PHOTOINHIBITION INDUCED BY DROUGHT WITH LOW LIGHT IN PEPPER LEAVES

以超辣9号辣椒品种为实验材料,采用聚乙二醇(PEG)模拟干旱胁迫,并利用水杨基氧肟酸(SHAM)抑制交替呼吸途径活性,研究了交替呼吸途径在防御弱光干旱(200μmol·m^(-2)·s^(-1) PAR,15%PEG)下辣椒叶片光抑制中的作用。结果表明:弱光干旱处理降低了辣椒叶片光化学能力,但诱导了热耗散和环式电子传递等能量耗散途径的增强,其光抑制程度较低;弱光干旱胁迫并未诱导辣椒叶片交替呼吸途径活性的明显上升,抑制交替呼吸途径后也未明显加剧光抑制程度;抑制交替呼吸途径虽然进一步降低了光化学能力,但也显著促进了热耗散和环式电子传递的进行。由此可见,弱光干旱胁迫下辣椒叶片主要通过热耗散和环式电子传递等叶绿体能量耗散途径防御光抑制的发生,交替呼吸途径并未起到明显作用。

In order to study the protective roles of alternative oxidase pathway （AOX pathway） in photoinhibition induced by drought with low light （200 ~mol.m2.s＂1 PAR, 15%PEG） in pepper leaves, a pepper cultivar ＂Chaola No.9＂ was selected as experimental material, and the AOX inhibitor salicylhydroxamic acid （1 mM; SHAM） was used to inhibit AOX activity in vivo. The results indicated that photochemical reaction decreased in leaves treated by drought with low light, however, only slight photoinhibition was occurred because of the increase of thermal energy dissipation and cyclic electron flows around photosystem I. Leaf AOX pathway was not up-regulated after drought with low light, and photoinhibition was not obviously deteriorated by inhibition of AOX pathway. Inhibition of AOX pathway under drought with low light decreased photochemical reaction, but increa^sed thermal energy dissipation and cyclic electron flows around photosystem I. Taken together, pepper leaves could increase chloroplastic energy dissipation pathways to alleviate photoinhibition induced by drought with low light, however, AOX pathway did not play a significant protective role.