稗草和水分胁迫对大豆植株根瘤固氮速率的交互影响

Interaction of Barnyardgrass and Water Stress on Nitrogen Fixation of Soybean

稗草和水分胁迫对大豆植株根瘤固氮速率有显著的交互影响。在旱、涝结合及座英期淹水条件下,稗草对大豆根瘤固氮的危害,明显比在正常供水条件下重,而在幼苗期～开花期渍涝条件下明显比在正常水分供应条件下轻,甚至化害为益。任何时期、任何种类的水分胁迫处理皆不利于大豆根瘤固氮,且旱害大于涝害,先涝后旱的危害大于先旱后涝的危害,旱、涝结合的危害大于单旱或单涝的危害,开花期渍涝的危害最重,鼓粒期渍涝的危害最轻;开花期至座英期,大豆根瘤固氮对旱涝结合+稗草干扰的交互危害最为敏感。

Barnyardgrass interference and water stress had a significant interaction on the nitrogen fixation of soybean. Barnyardgrass could reduce the nitrogen fixation of soybean to a greater extent under water stress by drought+waterlogging during all soybean growth stages or singel waterlogging during soybean pod setting stage, but to a less extent or stimulated it under waterlogging treatment during soybean seedling or flowing stages, compared to that under the normal soil moisture condition. Both drought and waterlogging decreased the mean soybean nitrogen fixation rate. Among them, the drought injury was greater than that of waterlogging injury, the injury of the water stress treatment ' First waterlogging and then drought' was greater than that of the opposite treatment ' First drought and then waterlogging ' , the injury of the stress combination ' Waterlogging+drought' was greater than that of a single drought or waterlogging. Moreover, waterlogging showed its greatest inhibition during soybean flowing stage and a least one during soybean pod filling stage. During the flowing and pod filling stage soybean nitrogen fixation was most sensitive to the interaction injure of the water stress by drought+waterlogging and barnyardgrass interference.