氮素形态及水分胁迫对水稻根系生理特性的影响

Effects of nitrogen form and water stress on root physiological characteristics of rice plants

采用室内营养液培养、聚乙二醇(PEG 6000)模拟水分胁迫的方法,在3种供氮形态下(NO3--N、NH4+-N和NO3--N与NH4+-N等体积混合),研究了在非水分胁迫及模拟水分胁迫(添加10%PEG,约相当于-0.15 MPa)下,苗期水稻根系的生长状况、水分吸收状况及木质部汁液特性。结果表明,水分胁迫抑制了供NO3--N营养水稻根系的生长,而对供NH4+-N水稻根系的生长没有影响;水分胁迫提高了NH4+-N营养水稻木质部汁液pH值,并增加其渗透势。提示:水分胁迫条件下,NH4+-N营养对根系生长及木质部汁液调节可能是氮素增强水稻抗旱性的原因之一。

By using the method of nutrient solution culture and simulated water stress by PEG 6000, the effects of different nitrogen forms （ NO3^- -N, NH4^＋ -N and NO3^- -N ＋ NH4^＋ -N） and water stress on root growth, water uptake and xylem sap of rice plants were studied. The results showed that the root growth of NO3^- -N supplied rice plants were inhibited under water stress, but not affected the roots growth of NH4^＋ -N supplied rice plants; water stress increased pH value and osmotic potential of xylem sap of NH4^＋ -N supplied rice plants. Under water stress, the regulation of different nitrogen forms nutrition on root growth and xylem sap might be a possible approach for the ammonium nutrition to enhanc the tolerance of drought stress.