光合电子流对光响应机理模型在超级晚稻光合特性研究中的应用

Application of mechanistic model of light-response of photosynthetic electron flow on photosynthetic characteristics in super late rice

【目的】了解光合电子流对超级晚稻光合特性的影响,进一步揭示植物捕光色素分子内禀参数对超级晚稻光合作用的影响机制,为超级晚稻高光效育种打下基础。【方法】利用LI-6400XT便携式光合测定系统测量不同超级晚稻品种的电子传递速率对光的响应曲线,利用叶氏光合机理模型分析超级晚稻光合特性差异及其产生的原因。【结果】叶氏光合机理模型可较好地拟合超级晚稻叶片的光合电子流对光的响应曲线,由此得到的最大电子传递速率(ETRmax)和饱和光强(PARsat)与实测值高度符合。超级晚稻品种的ETRmax和PARsat均显著高于对照汕优46(P<0.05),超级晚稻本征光能吸收截面(σik)较大,捕光色素分子处于最低激发态的最小平均寿命(τmin)较短。此外,捕光色素分子的有效光能吸收截面(σ′ik)和处于激发态的捕光色素分子(Nk)也影响着超级晚稻对光能的吸收和利用。【结论】超级晚稻通过捕光色素分子内禀参数影响光合电子流,进一步影响其光合特性。

【Objective】The purpose of the study was to understand the effects of photosynthetic electron flow on photosynthetic characteristics of super late rice,and reveal how the intrinsic parameters of plant light-harvesting pigment molecules affected photosynthesis of super late rice,and laid a foundation for breeding high photosynthetic efficiency varieties of rice.【Method】The light-response curves of photosynthetic electrons transfer rate to light of different super late rice varieties were measured by LI-6400XT portable photosynthesis measurement system. The differences in the photosynthetic characteristics and their courses were studied based on Ye model of light-response curves of photosynthetic electron flow.【Result】The Ye model could fit the response curve of photosynthetic electron flow of super late rice to light well, and the obtained fitted maximum electron transport rate(ETRmax) and saturated light intensity(PARsat)were highly consistent to the measured values. The maximum electron transport rate(ETRmax)and maximum electron transport rate(PARsat) of super late rice were significantly higher than those of control Shanyou 46(P<0.05),the super late rice had the greater eigen- absorption cross-section of light-harvesting pigments and the shorter minimum average lifetime(τ min)of photosynthetic pigment molecules in the excited state. Moreover,the effective light absorption cross-section(σ'ik)of light-harvesting pigment molecules and the light-harvesting pigment molecules(Nk)in the excited state were beneficial to absorption and utilization of light energy in super late rice.【Conclusion】Super late rice affects the photosynthetic electron flow by the characteristics of light-harvesting pigment molecules,further influence its photosynthetic characteristics.