Growth rate regulation is associated with developmental modification of source efficiency
Growth rate regulation is associated with developmental modification of source efficiency
复制标题
增长率调节与源效率的发育改变相关
作者：
N. Pullen;Naichao Zhang;Albor Dobon Alonso;S. Penfield
植物利用一套生长抑制因子根据季节和环境因素调节其生长速度，这些生长抑制因子直接与控制细胞分裂和生长的细胞机制相互作用。缺乏生长抑制因子的突变体表现出更高的生长速度1,2，但这些植物确保资源可用性以实现更快生长的机制尚不清楚。在这里，我们采用理论和实验相结合的方法对五重生长抑制突变体的快速生长表型进行了全面分析，以了解源库协调的生理基础。我们的研究结果表明，除了控制组织生长速度外，生长抑制因子还影响组织组成和叶片厚度，调节新光合能力的产生效率。建模表明，生长效率的提高是野生型和“刮刀”生长抑制突变体之间生长速率差异的基础，“刮刀”需要更少的碳来合成与野生型相当的光合能力，并且每单位质量固定更多的碳。我们得出结论，生长抑制因子通过控制叶片发育，调节源有效性和汇强度，以实现生长速率变化而不冒碳亏缺的风险。受赤霉素信号传导影响的五重突变体，与野生型相比，表现出更快和更强的生长，被用作理解源库协调的生理基础的工具。
Plants modulate their growth rate according to seasonal and environmental cues using a suite of growth repressors known to interact directly with cellular machinery controlling cell division and growth. Mutants lacking growth repressors show increased growth rates1,2, but the mechanism by which these plants ensure source availability for faster growth is unclear. Here, we undertake a comprehensive analysis of the fast-growth phenotype of a quintuple growth-repressor mutant, using a combination of theoretical and experimental approaches to understand the physiological basis of source–sink coordination. Our results show that, in addition to the control of tissue growth rates, growth repressors also affect tissue composition and leaf thickness, modulating the efficiency of production of new photosynthetic capacity. Modelling suggests that increases in growth efficiency underlie growth-rate differences between the wild type and spatula della growth-repressor mutant, with spatula della requiring less carbon to synthesize a comparable photosynthetic capability to the wild type, and fixing more carbon per unit mass. We conclude that through control of leaf development, growth repressors regulate both source availability and sink strength to achieve growth-rate variation without risking a carbon deficit. A quintuple mutant—affected in gibberellin signalling, as well as showing faster and enhanced growth compared to the wild type—is used as a tool to understand the physiological basis of source–sink coordination.