外源NO对Ca(NO_3)_2胁迫下番茄幼苗PSII功能及光能分配利用的影响

为探讨外源NO缓解番茄幼苗次生盐渍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喷施NO供体硝普钠(SNP)对80 mmol·L-1Ca(NO_3)_2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。结果表明,喷施SNP有效缓解了Ca(NO_3)_2胁迫对PSII的损伤,使第15天番茄幼苗叶片的PSII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(ΦPSII)、光化学荧光猝灭系数(q P)及吸收光能用于进行光化学反应(P)和非光化学耗散(Ex)的份额分别较胁迫处理显著提高了4.93%、39.31%、92.84%、39.00%、92.83%和10.33%;初始荧光(Fo)、非光化学荧光猝灭系数(NPQ)、双光系统间激发能分配不平衡偏离系数(β/α-1)和天线热耗散的份额(D)分别较胁迫处理显著降低了7.20%、13.22%、43.09%和24.70%。综上,外源NO能通过改善PSII光化学活性和增强PSII反应中心的非光化学耗散减轻Ca(NO_3)_2胁迫造成的光抑制,进而提高番茄幼苗的耐盐能力。本研究结果为利用外源NO缓解蔬菜设施生产的次生盐渍障碍提供了理论和技术依据。

Effect of Exogenous Nitric Oxide on PSH Function and Distribution and Utilization of Luminous Energy in Tomato Seedlings Under Stress of Ca(NO3)2

To explore the photo-physiological mechanism for exogenous nitric oxide (NO) relieving the damage of secondary salinization on tomato seedling,a hydrophonic experiment was carried out with tomato seedlings of Qin Feng Bao Guan as test material in greenhouse to investigate the effect of NO donor sodium nitroprusside (SNP) on PS Ⅱ photochemical efficiency,distribution of excitation energy and absorption and utilization of luminous energy by antenna pigment within tomato seedlings under stress of Ca(NO3)2 of 80 mmol·L-1 by the technique of chlorophyll fluorescence kinetics.The results indicated that spraying SNP effectively relieved the Ca (NO3)2 stress on PS Ⅱ damage.In addition,the maximum photochemical efficiency (Fv/Fm),antenna conversion efficiency (F'v/F'm),practical photochemical efficiency (ΦPSⅡ),photochemical fluorescence quenching quotient (qP),quotient of absorbed light used in photochemical reaction (P) and non-photochemical dissipation used for reaction center (P680) (Ex) were significantly increased by 4.93％,39.31％,92.84％,39.00％,92.83％ and 10.33％,respectively.Moreover,the original fluorescence (Fo),non-photochemical fluorescence quenching quotient (NPQ),the relative deviation (β/α-1) from full balance between two photosystems and quotient of absorbed light used in antenna heat dissipation (D) were significantly reduced by 7.20％,13.22％,43.09％ and 24.70％,respectively,which was compared with the stress in 15d after the treatment.In conclusion,the results indicate that exogenous NO can alleviate photo-inhibition caused by Ca(NO3) 2 stress by improving the photochemical activity of PS Ⅱ and enhancing non-photochemical dissipation of the PS Ⅱ center,and enhance the salt-tolerance of tomato seedlings,which provide theoretical and technical basis on utilizing exogenous NO to remit secondary salinization barriers.