基于光合电子流的超级早稻光合特性研究

Photosynthetic Characteristics of Different Super Early Rice Based on Mechanistic Model of Light-response of Photosynthetic Electron Flow

为了更好地揭示植物捕光色素分子内禀参数对超级早稻光合电子流的影响,探究超级早稻的光合特性差异及其产生的原因,本试验采用LI-6400XT便携式光合测定系统测量了不同超级早稻品种的电子传递速率对光的响应曲线,并利用光合电子流对光响应模型进行了拟合。结果表明,光合电子流对光响应模型在超级早稻上的拟合效果好,计算得到的最大电子传递速率和饱和光强与实测值高度符合。超级早稻品种的最大电子传递速率(ETRmax)和大部分品种的饱和光强(PARsat)显著高于金优402(CK),这与超级早稻捕光色素分子处于最低激发态的最小平均寿命(τmin)较短、本征光能吸收截面(σik)较大有关。此外,随着光强的增加,超级早稻捕光色素分子的有效光能吸收截面(σ′ik)下降缓慢,处于最低激发态的捕光色素分子数(Nk)增长速度较慢,这些都有利于超级早稻对光能的吸收和利用。本研究有助于进一步了解超级稻生长伏势的光合特性,为杂交稻超高产育种提供理论基础。

In order to reveal the photosynthetic electron flow responses to light intensity and the characteristics of light-harvesting pigment molecules in super early rice,the differences in the photosynthetic characteristics and causes of differences were studied.Furthermore,the light-response curves of electron transmission rate were measured by LI-6400 XT.The results showed that the light-response curves were well fitted on the super early rice,and measured values of maximum electron transmission rate(ETRmax)and saturated light intensity(PARsat)were highly matched to the calculated(nominal)values.The ETRmax and PARsat of super early rice were significantly higher than those of control,which was related to the greater eigen-absorption cross-section(σ′ik)of light-harvesting pigments and the shorter minimum average lifetime(Nk)of photosynthetic pigment molecules in the excited state.Moreover,σ′ik slowly decreased with increasing irradiance,and the Nk increased slowly.Both decreases were beneficial to absorption and utilization of light energy in super early rice.This research would help to further understand the photosynthetic characteristics of the growth advantage of super rice,and provide a theoretical foundation for breeding.