石地钱Reboulia hemisphaerica光系统Ⅱ对氮沉降的响应特征

Responses of Photosystem Ⅱ of Reboulia hemisphaerica to Nitrogen Deposition

对石地钱Reboulia hemisphaerica在不同模拟氮沉降条件下的叶绿素荧光动力学特征进行了研究。结果显示加氮对石地钱的光系统Ⅱ产生明显影响,40和60 kg.hm-2.a-1(以N质量计)处理对其光系统Ⅱ产生严重破坏。加氮导致植物单位面积捕获的光能降低,并导致PSⅡ反应中心电子受体侧的氧化还原状态及异质性发生变化,破坏电子传递链,叶片吸收的光能无法在电子传递链中消耗,迫使其大幅提高荧光和热耗散的比率以消耗掉电子传递链中的能量,从而使光系统Ⅱ的性能指数大幅下降。对推动力指数的分析显示,QA-后面的电子传递对加氮最为敏感。

Chlorophyll fluorescence transient kinetics of Reboulia hemisphaerica under different simulated nitrogen deposition conditions was studied. The results showed that nitrogen treatments caused changes of chlorophyll fluorescence transient of Reboulia hemisphaerica. N treatments affected PS Ⅱ by reducing the capacity of energy trap of unit area as well as changing the redox states and the heterogeneity of the filling up of the PS Ⅱ acceptor side, destroying the electron flow, especially the electron flow beyond Q2 , as a result, the absorbed energy can not be consumed in the electron flow and have.to be consumed by fluorescence and heat. It can be deduced from the JIP-test that 40 and 60 kg · hm^-2 · a^-1 treatments lead serious damages to Reboulia hemisphaerica.