• 关键词：水杨酸  高氯酸盐胁迫  水花生  叶绿素荧光参数

• 基金项目：云南省科技厅社会事业发展专项资助项目(No.2008CA020)

• 谢寅峰
• 南京林业大学森林资源与环境学院, 南京 210037

• 张千千
• 南京林业大学森林资源与环境学院, 南京 210037

• 刘伟龙
• 中国科学院水利部成都山地灾害与环境研究所, 成都 610041

• 白晓华
• 云南省环境科学研究院, 昆明 650034

• 蔡贤雷
• 南京林业大学森林资源与环境学院, 南京 210037

• 贾艳玲
• 南京林业大学森林资源与环境学院, 南京 210037

• 摘要：为了探讨外源水杨酸(SA)对高氯酸盐胁迫下水生植物生理响应的调节作用,本文以水花生为试材,在水培及可控条件下,研究不同浓度(0.05、0.1、0.2、0.4mmol·L^-1)的SA对高氯酸盐胁迫下水花生荧光特性的影响.结果表明,在整个试验期间,各浓度的SA处理能不同程度地抑制高氯酸盐胁迫引起的暗适应下叶绿素最小荧光产额(F₀)和天线色素热耗散(D)的升高,缓解PSⅡ潜在活性(F_v/F₀)、PSⅡ最大光化学效率(F_v/F_m)、PSⅡ有效光化学效率(F′_v/F′_m)、PSⅡ实际光化学效率(Φ_PSⅡ)、PSⅡ电子传递速率(ETR)和PSⅡ光化学反应能量耗散(P)的下降趋势,而对过剩光能耗散(E)的影响不明显.综合各荧光参数的变化,其中以0.2mmol·L^-1的SA处理缓解效果最佳,处理28d后各荧光参数的变化(除E值外)均与不加SA的胁迫组呈显著差异(p<0.05),外部形态的观察结果与荧光参数的变化结果也基本一致.以上结果说明适当浓度的SA能有效维持胁迫下叶肉细胞较高的光化学效率和电子传递速率,缓解由于过剩激发能的增加而引起的光抑制,减轻光合机构受伤害的程度,从而提高水花生抗高氯酸盐胁迫的能力.PSⅡ非辐射能量耗散的增强并非是高氯酸盐胁迫下SA保护光合机构的主要机制,有关机理尚待进一步研究.

• Abstract：Awater culture experiment was conducted on Alternanthera philoxeroides to study the effects of different concentrations of exogenous salicylic acid(SA)(0.05、0.1、0.2、0.4 mmol·L^-1)on the chlorophyll fluorescence parameters under perchlorate stress conditions. The results showed that in all SAtreatments,the increase of minimum fluorescence(F₀)and antenna dissipation (D) of PSⅡ under perchlorate stress were inhibited; the decrease of potential activity (F_v/F₀),maximal photochemical efficiency (F_v/F_m),effective photochemical efficiency (F′_v/F′_m),actual photochemical efficiency (Φ_PSⅡ),electron transport rate of PSⅡ (ETR) and photochemical dissipation (P) were alleviated to some extent; but the dissipation of excess energy (E) of PSⅡ was not obviously changed. Integrating the fluorescence parameters mentioned above,we consider that the optimal concentration of SAin alleviating perchlorate stress is 0.2 mmol·L^-1,as the fluorescence parameters (except E) of Alternanthera philoxeroides in the 0.2 mmol·L^-1 treatment were significantly different from those in the non-SAtreatment after 28 days (p<0.05). Therefore,exogenous SAtreatment could effectively maintain the photochemical efficiency and electron transport rate of mesophyll cells,alleviate the photoinhibition caused by the increase of excess excitation energy,relieve the damage to the photosynthetic apparatus under perchlorate stress,and therefore improve the ability of Alternanthera philoxeroides to resist perchlorate stress. Enhancing the non-radiant energy dissipation of PSⅡ was not the main reason for the protection of the photosynthetic apparatus of Alternanthera philoxeroides under perchlorate stress,and the action mechanism of SAin alleviating perchlorate stress remains to be further studied.

• Key words：salicylic acid  perchlorate stress  Alternanthera philoxeroides  chlorophyll fluorescence parameters

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