不同生育期水分胁迫对水稻根系生长及产量的影响

Effects of Water Stress on Root and Yield of Rice at Different Growth Stages

研究水分胁迫对水稻根系生长和产量的影响。以桂两优2号为材料,通过聚乙二醇(PEG-6000)模拟不同程度的水分胁迫,在水稻分蘖盛期和抽穗扬花期分别水分胁迫16 d,然后恢复正常供水。水分胁迫及复水10 d后测定水稻根系形态、根活力和干物质,成熟期测定产量。结果表明:分蘖盛期和抽穗扬花期适度的水分胁迫均能提高水稻根系活力;处于不同生育期的水稻根系对干旱的耐受程度不同,在分蘖盛期水分胁迫期间,轻、中度水分胁迫对水稻根长、根表面积、根体积的生长具有促进作用,复水后,促进效果不显著;而在抽穗扬花期水分胁迫期间,水分胁迫对水稻根系生长的抑制作用不显著,复水后,轻、中度水分胁迫处理的根系生长较对照旺盛。分蘖盛期复水10 d后,根干重和地上部干重均以对照最高;抽穗扬花期复水10 d后,轻、中度水分处理的根干重和地上部干重高于对照,中度水分处理的与对照差异显著;至成熟期时,分蘖盛期和抽穗扬花期受水分胁迫处理的根干重均高于对照;在分蘖盛期经历轻度水分处理的地上部干重和稻谷产量最高,抽穗扬花期的地上部干重和稻谷产量以对照最高。适宜的水分胁迫不会显著降低水稻产量;极重度水分胁迫没有抑制根系的生长,但水稻产量却显著降低。

In this study, the effects of the water stress on rice root and yield were studied. Gui liang you 2 was taken as material and polyethylene glycol（PEG--6000）was used to simulate the different degrees of water stress. After dealt with water stress for 16 days at tillering stage and heading stage respectively, the material was supplied with nutrition as normal. The morphological traits and activity and dry matter of rice root were measured after the period of re-watering, and grain yield was measured during the mature period. The results showed that： The root activity could be enhanced owning to moderate water stress at tillering and heading stage. The drought tolerance of rice root at different stages is not the same, the root length, root surface area, root volume can be promoted owing to mild or moderate water stress during water stress of tillering stage, the promoting effects is not significant after re-watering; while water stress at heading stage, the inhibitory action of water stress to root growth is not significant, the root of light, moderate water stress was stronger than that of the control after re- watering.Ten days after re-watering at tillering stage, the qualities of root dry matter and shoot dry matter of control were the highest. Ten days after re-watering at heading stage, the quantities of root dry matter and shoot dry matter with mild and moderate treatment higher than those of the control, and there was a drastic contrast between the qualities of root dry matter and shoot dry matter and those of the control. In maturation stage, the qualities of root dry matter dealt with all kinds of water stress at tillering and heading stag are higher than those of the control. However, it was only with mild treatment at tillering stage that the quality of shoot dry matter and grain yield were higher than that of the control, The quality of shoot dry matter and grain yield with normal water treatment at heading stage was up to its summit. The grain yield with suitable water stress at tillering and heading stage do not significant reduce the yield of rice. Severe water stress does not inhibit root growth, but it decreases the yield of rice significantly.