外源水杨酸和一氧化氮对盐胁迫番茄幼苗光系统Ⅱ功能及激发能分配利用的影响

【目的】 为了探明外源水杨酸 (SA) 和一氧化氮 (NO) 协同缓解番茄幼苗盐渍伤害的光合生理机制。 【方法】 以番茄品种‘秦丰保冠’为试材，在水培条件下，研究单独和复配施用外源SA、NO供体硝普钠 (SNP) 对100 mmol/L NaCl胁迫下番茄幼苗气体交换、光系统Ⅱ (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】 SA、SNP单独和复配处理均能有效缓解NaCl胁迫对PSⅡ的损伤，其中以SA和SNP复配处理效果最好，3～7 d番茄叶片净光合速率 (P_n)、PSⅡ最大光化学效率 (F_v/F_m)、天线转化效率 (F_v′/F_m′)、光化学荧光猝灭系数 (qP)、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) 分别较胁迫处理显著提高了25.5%～94.9%、9.5%～15.3%、25.7%～34.6%、38.8%～121.9%、74.2%～198.6%和22.2%～25.5%；初始荧光 (F_o)、PSⅡ非光化学荧光猝灭系数 (NPQ)、激发能压力 (1-qP)、反应中心非光化学耗散的份额 (E_x)、天线热耗散的份额 (D) 和双光系统间激发能分配不平衡偏离系数 (β/α-1) 分别较胁迫处理不同程度降低了19.8%～23.5%、22.8%～23.4%、32.5%～39.9%、15.1%～19.1%、27.8%～31.4%和51.8%～72.8%。 【结论】 外源SA和NO在保护PSⅡ及光合电传递链免受盐害损伤，提高番茄幼苗耐盐性方面具有协同增效作用。

Effects of exogenous salicylic acid and nitric oxide on PSⅡ function and distribution and utilization of excitation energy in tomato seedlings under NaCl stress

【Objectives】 This paper elucidated the photosynthetic physiological mechanism of salicylic acid (SA) and nitric oxide (NO) synergistically alleviate the salinity damage of tomato seedlings. 【Methods】 The effects of single and compound applications of SA and NO donor sodium nitroprusside (SNP) on PSⅡphotochemical efficiency, distribution of excitation energy and absorption and utilization of luminous energy by antenna pigment within tomato (‘Qin Feng Bao Guan’) seedlings under the 100 mmol/L NaCl stress were studied using the method of hydroponic nutrient solution. 【Results】 Single and combined applications of SA and SNP could effectively relieve the NaCl stress on PSⅡ damage. The combined application of SA and SNP gave the best stress relieving effect. After 3–7 days of stress treatment, the net photosynthetic rate (P_n), PSⅡmaximal photochemistry efficiency (F_v/F_m), antenna conversion efficiency (F_v′/F_m′), photochemical fluorescence quenching coefficient (qP), quotient of absorbed luminous energy used for photochemical action (P) and chlorophyll fluorescence decay rate (R_fd) were significantly increased by 25.5%–94.9%, 9.5%–15.3%, 25.7%–34.6%, 38.8%–121.9%, 74.2%–198.6% and 22.2%–25.5%, respectively. The original fluorescence (F_o), non-photochemical fluorescence quenching coefficient (NPQ), excitation pressure (1-qP), quotient of absorbed luminous energy used for non-photochemical dissipation in reaction center (E_x) and antenna heat dissipation (D), and the unbalanced distribution of coefficient deviation on excitation energy between two photosystems (β/α-1) were significantly reduced by 19.8%–23.5%, 22.8%–23.4%, 32.5%–39.9%, 15.1%–19.1%, 27.8%–31.4% and 51.8%–72.8%, respectively. 【Conclusions】 These results above show that exogenous salicylic acid and nitric oxide have synergistic effect in protecting PSⅡ and photosynthetic transport chain from salt damage and improving salt tolerance of tomato seedlings.