Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplu...Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.展开更多
Grain filling, a crucial stage of grain yield formation in rice, is usually affected by the panicle nitrogen （N） fertilization. Field and pot culture experiments were conducted to explore the underlying mechanisms o...Grain filling, a crucial stage of grain yield formation in rice, is usually affected by the panicle nitrogen （N） fertilization. Field and pot culture experiments were conducted to explore the underlying mechanisms of N effect. Two rice cultivars with high lodging resistance were grown in the field and pot. Four panicle N fertilization treatments were conducted in 2006 and repeated in 2007. The result showed that medium level of panicle N fertilization treatment （NM） enhanced the accumulation and translocation of non-structural carbohydrate （NSC） in the stem and sheath. Compared with non-nitrogen treatment （NO）, NM promoted the translocation of labeled ^13C from stem and sheath to grain. But, low level of panicle N fertilization treatment （NL） and high level of panicle N fertilization treatment （NH） showed the negative effect. The endosperm cell, grain length, and grain width of NM increased more quickly than that of NO from 4 to 10 d after anthesis. During the early period of grain filling, sucrose-phosphate synthase （EC 2.4.1.14, SPS） activity were significantly higher for the NM treatment than those of the NL and NH treatments. Sucrose synthase （EC 2.4.1.13, SuSase） activity in the grains was substantially enhanced by NM, with the duration of higher activity being longer than those of the other treatments. At maturing stage, NM significantly increased the filled grain number, the seed-setting rate, and the grain weight compared with NL and NH. The results suggest that NM have a positive effect on the activities of enzymes of physiological importance, thereby increasing the grain size and promoting grain filling.展开更多
为研究氮素穗肥对粳米淀粉理化特性和精细结构的影响,明确粳米食用特征与淀粉特性和结构的关系,以南粳9108和南粳0212为供试材料,在相同基蘖肥用量下设置3个穗肥施氮水平(0、45和135 kg N hm^(-2)),测定了不同处理下粳米的淀粉特性及其...为研究氮素穗肥对粳米淀粉理化特性和精细结构的影响,明确粳米食用特征与淀粉特性和结构的关系,以南粳9108和南粳0212为供试材料,在相同基蘖肥用量下设置3个穗肥施氮水平(0、45和135 kg N hm^(-2)),测定了不同处理下粳米的淀粉特性及其结构,分析了其与食用特征间的关系。施用氮素穗肥降低了粳米食味值,高氮下差异显著。硬度、弹性、黏性和平衡性的绝对值与总蛋白含量均随穗肥施氮量的增加而提高,表观直链淀粉含量则与之相反。在淀粉特性和结构方面,增施氮素穗肥提高了淀粉溶解度、膨胀势、糊化焓、小淀粉颗粒占比、相对结晶度、红外比值(1045/1022 cm^(-1)),降低了淀粉回生焓、回生度、大淀粉颗粒占比、淀粉平均直径和红外比值(1022/995 cm^(-1)),高氮影响更趋明显。施用氮素穗肥降低了表观直链淀粉含量,提高了淀粉表层的有序性和结晶区稳定性,淀粉粒径变小,进而阻碍了淀粉膨胀和糊化,米饭硬度升高,食用口感变差。适量施用氮素穗肥可实现粳稻优质丰产协同。展开更多
基金Funding was provided by the National Key Research and Development Program of China(2017YFD0301203,2017YFD0300100,and 2018YFD0300803)Jiangsu Agriculture Science and Technology Innovation Fund(CX(18)1002).
文摘Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.
基金supported by the National Natural Science Foundation of China (30871482)the Scientific Research Innovation Project for Graduate Student of Jiangsu Province, China (CXO7B_184Z)
文摘Grain filling, a crucial stage of grain yield formation in rice, is usually affected by the panicle nitrogen （N） fertilization. Field and pot culture experiments were conducted to explore the underlying mechanisms of N effect. Two rice cultivars with high lodging resistance were grown in the field and pot. Four panicle N fertilization treatments were conducted in 2006 and repeated in 2007. The result showed that medium level of panicle N fertilization treatment （NM） enhanced the accumulation and translocation of non-structural carbohydrate （NSC） in the stem and sheath. Compared with non-nitrogen treatment （NO）, NM promoted the translocation of labeled ^13C from stem and sheath to grain. But, low level of panicle N fertilization treatment （NL） and high level of panicle N fertilization treatment （NH） showed the negative effect. The endosperm cell, grain length, and grain width of NM increased more quickly than that of NO from 4 to 10 d after anthesis. During the early period of grain filling, sucrose-phosphate synthase （EC 2.4.1.14, SPS） activity were significantly higher for the NM treatment than those of the NL and NH treatments. Sucrose synthase （EC 2.4.1.13, SuSase） activity in the grains was substantially enhanced by NM, with the duration of higher activity being longer than those of the other treatments. At maturing stage, NM significantly increased the filled grain number, the seed-setting rate, and the grain weight compared with NL and NH. The results suggest that NM have a positive effect on the activities of enzymes of physiological importance, thereby increasing the grain size and promoting grain filling.
文摘为研究氮素穗肥对粳米淀粉理化特性和精细结构的影响,明确粳米食用特征与淀粉特性和结构的关系,以南粳9108和南粳0212为供试材料,在相同基蘖肥用量下设置3个穗肥施氮水平(0、45和135 kg N hm^(-2)),测定了不同处理下粳米的淀粉特性及其结构,分析了其与食用特征间的关系。施用氮素穗肥降低了粳米食味值,高氮下差异显著。硬度、弹性、黏性和平衡性的绝对值与总蛋白含量均随穗肥施氮量的增加而提高,表观直链淀粉含量则与之相反。在淀粉特性和结构方面,增施氮素穗肥提高了淀粉溶解度、膨胀势、糊化焓、小淀粉颗粒占比、相对结晶度、红外比值(1045/1022 cm^(-1)),降低了淀粉回生焓、回生度、大淀粉颗粒占比、淀粉平均直径和红外比值(1022/995 cm^(-1)),高氮影响更趋明显。施用氮素穗肥降低了表观直链淀粉含量,提高了淀粉表层的有序性和结晶区稳定性,淀粉粒径变小,进而阻碍了淀粉膨胀和糊化,米饭硬度升高,食用口感变差。适量施用氮素穗肥可实现粳稻优质丰产协同。
