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为探讨外源水杨酸(SA)缓解番茄幼苗盐胁迫伤害的光合生理机制,以‘秦丰保冠’番茄幼苗为试材,在水培条件下,利用叶绿素荧光动力学技术研究营养液中(1/4 Hoagland)施入SA(200μmol·L~(-1))对100 mmol·L~(-1) Na Cl胁迫下番茄幼苗PSⅡ光化学效率、激发能分配和天线色素吸收光能利用的影响。结果显示:Na Cl胁迫15 d内,SA处理的幼苗叶片PSⅡ潜在光化学活性(F_v/F_o)、最大光化学效率(F_v/F_m)、天线转化效率(F_v′/F_m′)、实际光化学效率(Φ_(PSⅡ))、光化学荧光猝灭系数(q_P)、吸收光能用于进行光化学反应的份额(P)和叶绿素荧光衰减率(R_(fd))不同程度升高;P_(SⅡ)非光化学荧光猝灭系数(NPQ)、激发能压力(1–qp)、天线热耗散的份额(D)、光合功能相对限制值(L_(PFD))和双光系统间激发能分配不平衡偏离系数(β/α–1)明显降低;PSⅡ反应中心非光化学耗散的份额(E_x)变化无明显规律。以上结果表明,外源SA可以通过提高PSⅡ光化学活性来减轻盐胁迫导致的光抑制,进而促进了番茄幼苗的生长发育。
In order to investigate the photosynthetic mechanism of exogenous salicylic acid (SA) to alleviate the salt stress injury of tomato seedlings, the seedlings of ’Qinfeng Bao’guang’ were used as materials to study the effects of exogenous salicylic acid / 4 Hoagland) on the photochemical efficiency of PS Ⅱ, the allocation of excitation energy and the utilization of the light energy absorbed by the aerial part of tomato seedlings under 100 mmol·L -1 NaCl stress. The results showed that the potential photochemical activities (F_v / F_o), maximum photochemical efficiency (F_v / F_m), antenna conversion efficiency (F_v ’/ F_m’) and actual photochemical efficiency (Φ_ (PSⅡ), photochemical quenching coefficient (q_P), and fraction (P) of absorption of photochemical reaction and decay rate of chlorophyll fluorescence (R_ (fd)) increased to some extent. P_ (SⅡ) (NPQ), excitation pressure (1-qp), antenna heat dissipation fraction (D), relative limit of photosynthetic function (L PFD) and unbalanced excitation energy distribution bias between two systems β / α-1). There was no obvious change in the proportion of non-photochemical dissipation (E_x) in PSⅡ reaction center. The above results show that exogenous SA can alleviate the photoinhibition induced by salt stress by increasing the photochemical activity of PSII, and then promote the growth and development of tomato seedlings.