【摘要】 研究短期淹水对土壤氧浓度的影响及不同叶龄水稻幼苗生物量、株高和根系氮代谢关键酶活性的影响,探讨短期淹水影响水稻幼苗生长和根系氮代谢的生理机制。试验分别在小拱棚自然光照条件下和人工气候箱中进行,共设置5个处理:全程无淹水处理(CK)、一叶一心期到二叶一心期淹水处理(T1)、二叶一心期到三叶一心期淹水处理(T3)、三叶一心期到四叶一心期淹水处理(T3)、全程淹水处理(T4)。结果表明,在淹水条件下,育秧土中的氧浓度迅速下降,在大约5 h后接近零,撤除淹水处理后,随着土壤中重力水的流失,在不到5 h内,土壤中的氧浓度迅速升高至大气氧浓度状态;不管是从哪个叶龄期开始,淹水处理在短期内促进了水稻幼苗生长,其地上部、地下部鲜质量均比对照增加;不同叶龄期实施的短期淹水处理对水稻根系硝酸还原酶、谷氨酰胺合成酶、谷氨酸合成酶活性的影响基本一致,多数情况下降低了各种氮代谢酶的活性。不同叶龄期短期淹水处理对秧苗的影响并无明显差别,尽管如此,三叶期前短期缺氧处理对水稻幼苗根系氮代谢酶活性的短期影响不同于分蘖期及以后短期缺氧处理的影响。更多还原

【Abstract】 This study was conducted to research the effects of short-term submergence on soil oxygen concentration and the effects of the biomass, plant height of rice seedlings and the activities of key enzymes of nitrogen metabolism in roots, and explore the physiological mechanism of short-term submergence on rice seedling growth and root nitrogen metabolism. The experiment was carried out under natural light condition in small arched shed and in artificial climate box, respectively. Five treatments were set: non submergence treatment(CK), submergence treatment from one-leaf and one-heart stage to two-leaf and one-heart stage(T1), submergence treatment from two-leaf and one-heart stage to three-leaf and one-heart stage(T3), submergence treatment from three-leaf and one-heart stage to four-leaf and one-heart stage(T3) and submergence treatment in whole process(T4). At the beginning and end of each submergence treatment, the rice seedling biomass, plant height and key enzyme activities of nitrogen metabolism in root were analyzed. The results showed that under flooding conditions, the oxygen concentration in the seedling soil dropped rapidly and approached zero after about 5 hours. After the flooding treatment was removed, with the loss of gravitational water in the soil, the oxygen concentration in the soil was less than 5 hours rapidly increase to atmospheric oxygen concentration state; no matter from which leaf age, the short-term submergence treatment promoted the growth of rice seedlings in a short time, and the fresh weight of shoot and underground root increased compared with the control. The effects of short-term submergence on the activities of key enzymes of nitrogen metabolism were basically the same at different leaf ages, and in most cases, the activities of various nitrogen metabolism enzymes were decreased. The effects of short-term submergence on rice seedlings in different leaf ages were basically the same. However, the effects of short-term submergence before three leaf stage on the activities of nitrogen metabolism enzymes in rice seedling roots were different from those at and after tillering stage.更多还原