Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Garzón 809, Montevideo, Uruguay.
Instituto Nacional de Investigación Agropecuaria (INIA), Unidad de Biotecnología. Estación Experimental Wilson Ferreira Aldunate, Ruta 48, Km 10, Rincón del Colorado, 90200, Canelones, Uruguay.
Photosynth Res. 2019 Apr;140(1):51-63. doi: 10.1007/s11120-018-0605-x. Epub 2018 Nov 17.
One of the main limitations of rice yield in regions of high productive performance is the light-use efficiency (LUE). LUE can be determined at the whole-plant level or at the photosynthetic apparatus level (quantum yield). Both vary according to the intensity and spectral quality of light. The aim of this study was to analyze the cultivar dependence regarding LUE at the plant level and quantum yield using four rice cultivars and four light environments. To achieve this, two in-house Light Systems were developed: Light System I which generates white light environments (spectral quality of 400-700 nm band) and Light System II which generates a blue-red light environment (spectral quality of 400-500 nm and 600-700 nm bands). Light environment conditioned the LUE and quantum yield in PSII of all evaluated cultivars. In white environments, LUE decreased when light intensity duplicated, while in blue-red environments no differences on LUE were observed. Energy partition in PSII was determined by the quantum yield of three de-excitation processes using chlorophyll fluorescence parameters. For this purpose, a quenching analysis followed by a relaxation analysis was performed. The damage of PSII was only increased by low levels of energy in white environments, leading to a decrease in photochemical processes due to the closure of the reaction centers. In conclusion, all rice cultivars evaluated in this study were sensible to low levels of radiation, but the response was cultivar dependent. There was not a clear genotypic relation between LUE and quantum yield.
在高生产力地区，水稻产量的主要限制因素之一是光能利用效率（LUE）。LUE 可以在整株水平或光合器官水平（量子产量）上确定。这两者都根据光的强度和光谱质量而变化。本研究旨在分析四个水稻品种和四个光环境下，LUE 在植株水平和量子产量上的品种依赖性。为此，开发了两个内部光照系统：光照系统 I 产生白光环境（400-700nm 波段的光谱质量），光照系统 II 产生蓝红光环境（400-500nm 和 600-700nm 波段的光谱质量）。光环境影响了所有评估品种的 LUE 和 PSII 的量子产量。在白光环境中，当光强度增加一倍时，LUE 降低，而在蓝红光环境中，LUE 没有差异。PSII 中的能量分配由叶绿素荧光参数确定的三个去激发过程的量子产量决定。为此，进行了淬灭分析和弛豫分析。只有在白光环境中低水平的能量才会导致 PSII 的损伤，从而由于反应中心的关闭而减少光化学过程。总之，本研究中评估的所有水稻品种对低辐射水平都很敏感，但反应取决于品种。LUE 和量子产量之间没有明确的基因型关系。
