College of Agriculture, South China Agricultural University, Guangzhou, China.
College of Agriculture and Life Science, North Carolina State University, NC, United States.
Sci Rep. 2016 Aug 25;6:32148. doi: 10.1038/srep32148.
Nitrogen availability and illumination intensity are two key factors which affect rice growth. However, their influences on total nitrogen accumulation, photosynthetic rate, root morphologies, and yields are not fully understood. We conducted two field experiments to (1) evaluate the effects of shading under different N treatments on photosynthetic parameters, root morphologies, total nutrient accumulation, and grain yields of rice; and (2) elucidate the relationship between total nutrient accumulation and root morphologies under different shading conditions and nitrogen treatments. Three nitrogen rates, three shading treatments, and three different rice cultivars were used in two field experiments. Double shading during the grain-filling stage decreased total nutrient accumulation, altered root morphological characteristics, and decreased yields in rice. There were also significant interaction effects between nitrogen and shading on photosynthetic rate, transpiration rate, and total root length, root superficial area, and root volume. Significant interactions were found among cultivars and shading for photosynthetic rate and transpiration rate. Correlation analysis revealed that total nitrogen accumulation (TNA) and potassium accumulation (TKA) were significantly positively correlated with total root length, root superficial area, and root volume. N application could alleviate the detrimental effects of shading on total nutrient accumulation and grain yield in rice.
氮素供应和光照强度是影响水稻生长的两个关键因素。然而，它们对总氮积累、光合速率、根系形态和产量的影响尚不完全清楚。我们进行了两项田间试验，（1）评估不同氮处理下遮荫对水稻光合参数、根系形态、养分总积累和籽粒产量的影响；（2）阐明不同遮荫条件和氮处理下总养分积累与根系形态的关系。在两项田间试验中，使用了三种氮水平、三种遮荫处理和三种不同的水稻品种。灌浆期双重遮荫降低了总养分积累，改变了根系形态特征，降低了水稻产量。氮和遮荫对光合速率、蒸腾速率和总根长、根表面积和根体积也有显著的互作效应。在光合速率和蒸腾速率方面，品种和遮荫之间存在显著的互作。相关分析表明，总氮积累（TNA）和钾积累（TKA）与总根长、根表面积和根体积呈显著正相关。施氮可以缓解遮荫对水稻总养分积累和籽粒产量的不利影响。
