氮素形态及水分胁迫对不同水稻品种苗期生长的影响

The Effects of Nitrogen Forms and Water Stress on the Growth of Seeding Stage among Different Rice Cultivars

氮素调控对水分胁迫条件下水稻生长发育具有显著影响,但不同供氮形态调控水稻水分胁迫的生理机制尚缺乏深入研究。以籼稻品种(汕优63、扬稻6号)和粳稻品种(86优8、武运粳7号)为研究材料,采用室内营养液培养和聚乙二醇(PEG6000)模拟干旱胁迫处理,于不同供氮形态(NH+4-N和NO-3-N)条件下,研究不同氮素形态及水分条件对不同水稻品种苗期生长发育和光合特性的影响。结果表明,在两种水分条件下,供NH+4-N处理水稻生物量均显著高于供NO-3-N处理,在干旱胁迫条件下表现出较强抗旱性。与非水分胁迫条件相比,模拟干旱胁迫条件下供NH+4-N处理水稻蒸腾速率和气孔导度表现为增加的趋势,且叶面积和叶绿素含量没有显著影响,但供NO-3-N处理水稻的叶面积和叶绿素含量显著减少,进而引起供NO-3-N处理水稻净光合速率和干物质量显著下降。与非水分胁迫条件相比,模拟水分胁迫条件下粳稻品种生物量和叶面积均显著下降;但对籼稻品种而言,生物量和叶面积对水分胁迫的响应受氮素形态的显著影响,其中供NO-3-N处理模拟水分胁迫条件下显著降低,而对供NH+4-N处理没有显著影响。因此,籼稻品种在供NH+4-N条件下能够维持较高的叶片净光合速率和蒸腾速率,从而具有较强的抗旱能力。

In order to study the drought resistance and its response to nitrogen forms among the different rice cultivars,water culture experiments were carried out with different nitrogen forms and water stress. Four varieties（ Yangdao 6#,Shanyou 63#,Wuyunjing 7# and86 you 8#） were used in this paper. Plants supplied with ammonium nutrition had significantly higher total dry weight per plant and leaf area than those supplied with nitrate nutrition under the same water conditions. Compared to non-stress treatment,plants supplied with ammonium nutrition had higher transpiration rate and stomatal conductance and the same leaf area and chlorophy content（ SPAD value） under water stress condition. However,water stress dramatically reduced leaf area and chlorophy content on plants supplied with nitrate nutrition,and caused markedly decrease in net photosynthetic rate and transpiration rate. In comparison with non-stress treatment,Japonica rice plants had much lower total dry weight per plant and leaf area under water stress conditions. Nevertheless,they were significantly affected by nitrogen forms for Indica rice under water stress conditions. As compared to non-stress treatment,Indica rice plants supplied with nitrate nutrition had much lower total dry weight per plant and leaf area under water stress conditions. However,there is no significant effect on Indica rice supplied with ammonium nutrition under water stress conditions. In the development of upland-cultivated rice,Indica rice varieties,supplying with ammonium nitrogen can be choosen to increase its drought resistance,to maintain high net photosynthetic production during growth period.