不同水分条件下水稻根系生长与产量变化关系研究

大田试验条件下设置常规水稻和覆草旱作水稻两个处理，研究不同水分条件下水稻根系生长对水稻产量的影响。结果表明：旱作水稻根冠比较常规水稻高23.2%。常规水稻最大根深为28cm，旱作水稻为35cm。水稻旱作后根系呼吸强度有明显增加。早造常规水稻断根后产量下降15%~23%，而旱作水稻断1/4根产量增加约20%。晚造常规水稻断根处理之间产量没有显著性差异，而旱作水稻断3/4根处理产量较不断根处理下降20.4%。早造水稻断根不利于水稻贮存物质输出而有利用于净光合产物积累。断根后旱作水稻穗增重增加，而常规水稻断根后穗增重下降。晚造旱作水稻断根后贮存物质输出减少，断1/4根处理水稻净光合生产量有升高趋势，但断根过多则引起净光合生产量下降，最终导致穗增重下降。常规水稻断根后对贮存物质的输出影响不大，断1/4根水稻净光合生产量有升高趋势，但断根过多则导致净光合生产量的下降。

Study on the Relationship of Root Growth and Yield of Rice in Different Water Condition

Field experiments with two treatments that were normal paddy rice and aerobic rice with straw mulching were set up to explore the relationship of root growth and yield of Rice in different water condition. The result showed that: The root/shoot ratio of aerobic rice was 23.2% higher than that of normal paddy rice. The maximum deepth of rice root was 28cm for normal paddy rice and 35cm for aerobic rice. From paddy to aerobic condition the respiration intensity of rice root increased obviously during grain-filling period. In the first season the range of yield decrease of root-cutting treatments for normal paddy rice was from 15% to 23%. However, the yield of aerobic rice with 1/4 root-cut treatment increased about 20%. In the second season the yields among treatments with root-cutting for normal paddy rice were not significantly difference, but for aerobic rice the yields declined with the degree of root cut off. The yield of treatment with 3/4 root-cut in aerobic rice decreased about 20.4% and the difference was significantly. In the first season root-cutting was in disadvantage of exportating reserved assimilate but was in advantage of concurrent photoassimilate accumulation. At last the weight of spiklet of aerobic rice increased with root-cutting whereas normal paddy rice decreased. In the second season, for aerobic rice the export of reserved assimilate decreased with root-cutting, whereas the concurrent photoassimilate increased with 1/4 root cut-off. Excessive root-cutting would bring down the accumulation of concurrent photoassimilate and result in the decrease of spiklet. For normal paddy rice root-cutting did not have much effect on the reserved assimilate exporting and concurrent photoassimilate increased with 1/4 root-cut treatment, but excessive root-cutting brought down the net accumulation of concurrent photoassimilate.