胁迫萌发与不同水分胁迫强度下水稻对供氮形态的响应

The responses of rice to nitrogen form under stress germination method and different water stress intensity

采用营养液培养及聚乙二醇(PEG6000)模拟水分胁迫的方法,比较了3种供氮形态(NO3--N、NH4+-N和NO3--N与NH4+-N等体积混合)、3种水分条件(非水分胁迫、50 mg.L-1和100 mg.L-1PEG胁迫)和3种种子萌发方式(正常萌发、50 mg.L-1和100 mg.L-1PEG萌发)对水稻由苗期至分蘖期生长的响应。结果表明:在2种强度的水分胁迫条件下,3种供氮形态处理中始终以NH4+-N营养条件下水稻的生物量最高;在水分胁迫条件下,除NH4+-N外,其余2种供氮形态中水稻(包括正常萌发和胁迫萌发)光合同化物均被相对优先分配至根系;此外,胁迫萌发较正常萌发相比,不仅提高3种供氮形态下苗期至分蘖期水稻的生物量,而且还提高了水分胁迫条件下NH4+-N营养条件下水稻对氮、磷的利用率。

The rice growth from seedling stage to tillering stage were studied by using the method of nutrient solution culture. The experiment contained treatments of three nitrogen forms （ NO3^- - N, NH4^＋ - N, and the mixture of NO3^- - N and NH4^＋ - N）, three water status （non water stress, 50 mg ·L^-1 PEG stress and 100 mg ·L^-1 PEG stress） and three germination methods （normal germination, 50 mg ·L^-1 and 100 mg ·L^-1 PEG stress germination）. The results indicated that： dry biomass of rice plants under water stress supplied with NH4^＋ - N was higher than those of the other two nitrogen forms supplied. Under water stress, assimilates of rice plants including those from normal germination or stress germination were preferably transported to roots except those which were supplied with NH4^＋ - N. Furthermore, stress germination could increase the dry biomass of rice plants at seedling to tillering stage. And compared with normal germination, stress germination could improve nitrogen and phosphorus use efficiency of rice plants.