氮素对扬稻6号谷壳性状的影响及其原因分析

Effects of Nitrogen on Hull Characters and Its Causes in Yangdao6

在群体水培和盆栽条件下 ,研究氮素处理对扬稻 6号谷壳大小、重量和充实程度的影响及其与植株养分含量的关系。结果表明 ,与不施肥相比 ,适当降低移栽至抽穗期的供氮浓度或于生育前期施用氮肥 ,有利于增加谷壳大小和重量 ;提高移栽至抽穗期的供氮浓度或于生育中期较多施用穗肥 ,则抑制谷壳的生长和发育 ,使谷壳的大小、重量和充实度均显著下降 ,且施氮量越多 ,谷壳受抑的程度越大 ;施用粒肥有利于谷壳的物质积累 ,对谷壳大小影响较小。氮素处理对水稻谷壳性状的调节效应从大到小依次为谷壳重、单位面积谷壳重、谷壳面积、谷壳长度、谷壳宽度。相关分析表明 ,谷壳性状与抽穗期植株的含氮率呈极显著负相关 (r=- 0 .86 84 ～ - 0 .9336 ) ,与可溶性糖和淀粉含量呈正相关 (r=0 .6 6 6 0 NS～ 0 .95 0 1 )。水稻谷壳性状的改良有利于谷粒同化产物的积累 ,进而使粒重大幅度提高 (r =0 .6 388 ～ 0 .95 74 )

The experiments were carried out under solution and pot cultural conditions with Yangdao6. Effects of nitrogen on hull size, weight and plumpness were analysed. The results showed that compared with no fertilizer, reducing N supplying concentration from transplanting to heading properly or employing basal or tiller promoting fertilizer would result in increment of hull size and weight. While raising N supplying concentration from transplanting to heading or employing spikelet promoting or spikelet sustaining fertilizer would result in smaller, lighter hull and poorer hull plumpness. The more amount of nitrogen applied, the more effect on hull growth and devlopment. Top dressing at heading would redound to substance accumulation of hull, but have no effects on hull size. The sequence of variation of hull characters from the biggest to the smallest were hull weight, hull weight per unit area, hull area, hull length and hull width. Hull characters were significantly correlated with the nitrogen content of the plant at heading, with correlation coefficient from -0.8684 ** to -0.9336 ** , and positively correlated with the content of soluble and insoluble carbohydrates at that time, with correlation coefficient of 0.6660 NS -0.9501 ** . Improving hull characters would be beneficial to substance accumulation of grain, and would result in increment of grain weight(r=0.6388 *-0.9574 ** ).