水稻水作与旱作对抽穗后剑叶光合特性、衰老及根系活性的影响

Effect of Rice Cultivated under Paddy and Upland Condition on Photosynthesis and Senescence of Flag Leaf and Activity of Root System After Heading

对水稻水作与旱作栽培模式下水稻衰老和后期一些生理活性的影响进行了研究。结果表明 ,由于水分的影响 ,水稻旱作不同程度加速了水稻生理机能的衰退 ,使籽粒干物质积累受阻 ,粒重下降而减产。水稻水作不仅改善了水稻剑叶光合因子 ,提高了光合效率 ,而且剑叶呼吸速率下降缓慢 ,相对电导率上升缓慢 ,SOD酶活性较高 ,MDA含量低 ,表明剑叶后期衰老进程慢 ,促进籽粒增重 ,产量高。此外 ,旱作水稻生育末期根系干物质积累、活力高及代谢旺盛的优势对籽粒增重也是一种负向影响 ;而水稻水作开花 -灌浆期根系活力高 ,生育末期根系生理活性迅速衰退 ,保证了籽粒的充实。

Under paddy and plastic film upland condition, the senescence of rice and some physiological activities were studied. The results showed that upland cultivation of rice obviously affected the senescence. For the upland cultivation mode, rice was subjected to water stress, and the decrease rate of the physiological activity speeded up, then the rate accumulation of dry weight in grain slowed down and seed setting percentage reduced. As a result, the output reduced. Paddy of rice improved the factors of flag leaf photosynthesis and increased the rate of photosynthesis. Besides, the slow decrease of respiration rate of flag leaf, the slow increase of relative conductivity of flag leaf, the high superoxide dismutase (SOD) activity and the low malondialdehyde (MDA) content of flag leaf suggested the slow senescence of flag leaf, so the output of paddy rice was higher. The accumulation of dry weight, the high activity and vigorous metablism of root system of upland rice during later growing stage had a negative influence on grain filling, but the high activity of root system during flowering filling stage and the fast decline of physiological activity of root system during later growing stage promoted grain filling.