Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China.
Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China; and Corresponding authors. Email:
Funct Plant Biol. 2021 Jan;48(2):206-217. doi: 10.1071/FP20104.
Rice undergoes leaf senescence accompanied with grain filling when the plants reach the end of their temporal niche, and a delay in leaf senescence ultimately improves the yield and quality of grain. To estimate the decline in photosynthesis during leaf senescence and to find an efficient and useful tool to identify rice genotypes with a longer duration of active photosynthesis, we examined PSII photosynthetic activity in the flag leaves of japonica rice Shennong265 (SN265) and Beigeng3 (BG3) during leaf senescence using chlorophyll a fluorescence kinetics. The results show that inhibition occurred in the electron transport chains, but the energetic connectivity of PSII units was not affected as dramatically during leaf senescence. PSII reaction centres (RCs) were transformed into 'silent RCs,' and the chlorophyll content decreased during leaf senescence. However the size of the 'economic' antennae increased. Further, the percentage of variation of the specific energy flux parameters can rationally be used to indicate leaf senescence from the perspective of energy balance. Although the performance indices were more sensitive than other functional and structural JIP-test parameters, they still did not serve as an indicator of crop yield.
在植物达到时间生态位的末端时，水稻会经历叶片衰老伴随籽粒灌浆，延迟叶片衰老最终会提高产量和改善谷物品质。为了估计叶片衰老过程中光合作用的下降，并找到一种有效和有用的工具来鉴定具有更长时间活跃光合作用的水稻基因型，我们使用叶绿素荧光动力学研究了粳稻神农 265（SN265）和北粳 3 号（BG3）旗叶在叶片衰老过程中的 PSII 光合活性。结果表明，电子传递链发生了抑制，但在叶片衰老过程中，PSII 单位的能量连通性并没有受到如此剧烈的影响。PSII 反应中心（RC）转化为“沉默 RC”，叶绿素含量在叶片衰老过程中下降。然而，“经济”天线的大小增加了。此外，特定能量通量参数的变化百分比可以从能量平衡的角度合理地用于指示叶片衰老。尽管性能指数比其他功能和结构 JIP 测试参数更敏感，但它们仍然不能作为作物产量的指标。
