孕穗期冷水灌溉对寒地粳稻根系生长及产量的影响

以东农428和松粳10为试验材料,分别冷水灌溉处理0、3、6、9、12、15 d,分析孕穗期冷水灌溉对寒地粳稻根系形态、伤流强度、干物质积累及产量的影响,旨在探究孕穗期低温胁迫下寒地粳稻根系生长规律及其与产量关系。结果表明,与对照相比,孕穗期冷水灌溉下,寒地粳稻根系形态、伤流强度、根部与地上部干重及产量变化规律一致,冷水灌溉持续时间越长,降幅越大。冷水灌溉加快寒地粳稻生育中后期根系衰竭。孕穗期冷水灌溉抑制寒地粳稻根系发生和伸长,齐穗期根系形态和根干物质量显著下降,不利于生育中后期根系对营养物质吸收,地上部干物质积累减缓,地上部向根部运输有机质减少,根系活力降低,根系衰竭加快,致产量下降。孕穗期冷水灌溉下东农428中后期根系形态、根干重、根系活力维持在相对较高水平,地上部干物质积累量和产量变化幅度较小,是东农428耐冷性强于松粳10的主要原因。

Effect of cold-water irrigation at booting stage on root growth and yield of japonica rice in cold-region

Two japonica rices(Dongnong428 and Songjing10) were subjected to cold-water irrigation for six varying length of time(0, 3, 6, 9, 12 and 15 d) at booting stage, the root morphology,root bleeding intensity, dry matter accumulation, and yield were measured, respectively. In order to investigate the relationship between root growth and yield of japonica rice in cold-region under coldwater irrigation at booting stage. The results showed that compared with the control, the changes of cold-water irrigation at booting stage on root morphology, root bleeding intensity, root and shoot dry weight, and yield of japonica rice in cold-region were consistent. The amplitude of decrease for every indicator increased gradually with lengthening cold-water irrigation time. Cold-water irrigation accelerated root senescence of japonica rice in cold-region at medium-late stage. Cold-water irrigation inhibited the elongation and development of japonica rice root in cold-region at booting stage and significantly decreased root morphology and root dry weight at full heading stage, which was disadvantaged for the nutrient absorption of roots at medium-late stage. As a result, the accumulations of the shoot dry matter were slowed down, which could lead to the decrease of the transportion of organic matter to the root,and decreased the root activity, and accelerated the root senescence, and ultimately decreased the yield. The higher root morphology, root dry weight and root activity of Dongnong428 at medium-late stage after cold-water irrigation at booting stage, the smaller amplitude of decreasing on the accumulation of shoot dry matter and yield, which was the main reason why Dongnong428 was better than Songjing10 at cold resistance.