Jiao Nian Yuan, Li Ya Hui, Yang Xiao, Yin Fei, Ma Chao, Qi Fu Guo, Liu Ling, Xiong Ying
College of Agriculture, Henan University of Science and Technology, Luoyang 471003, Henan, China.
Ying Yong Sheng Tai Xue Bao. 2016 Sep;27(9):2959-2967. doi: 10.13287/j.1001-9332.201609.019.
To get better insight into the photosynthetic mechanism of plant adaptation to strong light in intercropped maize, a field trial was carried out in 2014-2015 to investigate the effects of maize/peanut intercropping row ratio and phosphate fertilizer on diurnal variation in light intensity of maize canopy, SPAD value, and the curves of photosynthetic response of net photosynthetic rate (P) to photon flux density (PFD) and to CO of functional leaves. The field trial comprised 2 rows maize intercropped with 2 rows peanut (2:2, R), 2 rows maize intercropped with 4 rows peanut (2:4, R) and 2 rows maize intercropped with 8 rows peanut (2:8, R). Results showed that the light intensity of intercropped maize canopy was R>R>R. From pre-tasselling to filling stage, the SPAD value, apparent quantum efficiency (AQY), light compensation point (LCP), light saturation point (LSP), maximum net photosynthetic rate, carboxylation efficiency (CE), maximum electron transfer rate (J), triose phosphate utilization (TPU), stomatal conductance (g), transpiration rate (T) and P in ear leaves of intercropped maize were R>R>R, but the intercellular CO concentration (C) was R>R>R. At dough stage, the AQY, LSP, g, CE, J and TPU in ear lea-ves of intercropped maize in R intercropping system were lower than those in R intercropping system. The photosynthetic indices, such as AQY, LSP, CE, V, J and TPU were increased by phosphate fertilizer application. These results suggested that the key mechanisms that enhanced strong light utilization ability of intercropped maize were attributed to gradual improvement in g, AQY, CE, V, J and TPU of ear leaves with increasing light intensity, however, beyond a certain light intensity, intercropped maize leaves were prone to premature senescence. Nonetheless, phosphate fertilizer could improve light utilization and delay leaf senescence in intercropped maize.
为了更深入了解间作玉米中植物适应强光的光合机制，于2014 - 2015年进行了田间试验，以研究玉米/花生间作行比和磷肥对玉米冠层光强日变化、SPAD值以及功能叶净光合速率（P）对光合有效辐射（PFD）和CO2的光合响应曲线的影响。田间试验包括2行玉米与2行花生间作（2:2，R）、2行玉米与4行花生间作（2:4，R）以及2行玉米与8行花生间作（2:8，R）。结果表明，间作玉米冠层的光强为2:8，R＞2:4，R＞2:2，R。从抽雄前期到灌浆期，间作玉米穗位叶的SPAD值、表观量子效率（AQY）、光补偿点（LCP）、光饱和点（LSP）、最大净光合速率、羧化效率（CE）、最大电子传递速率（J）、磷酸丙糖利用（TPU）、气孔导度（g）、蒸腾速率（T）和P为2:8，R＞2:4，R＞2:2，R，但胞间CO2浓度（Ci）为2:2，R＞2:4，R＞2:8，R。在蜡熟期，2:8间作系统中间作玉米穗位叶的AQY、LSP、g、CE、J和TPU低于2:4间作系统。施用磷肥提高了光合指标，如AQY、LSP、CE、V、J和TPU。这些结果表明，增强间作玉米强光利用能力的关键机制归因于穗位叶的g、AQY、CE、V、J和TPU随着光强增加而逐渐提高，然而，超过一定光强后，间作玉米叶片容易过早衰老。尽管如此，磷肥可以提高间作玉米的光利用并延缓叶片衰老。
