采用室内营养液培养及聚乙二醇(PEG6000)模拟水分胁迫处理的方法,在3种供氮形态(NH4^+/NO3^-比为100/0,50/50和0/100)和2种水分条件(非水分胁迫及水分胁迫)下,研究了水稻苗期-分蘖期的生长及其水分利用效率.结果表明,苗期-分蘖期水稻在非水分胁迫条件下,NH4^+/NO3^-比为50/50处理(NH4^+、NO3^-混合处理)的生物量最大,比单一供NH4^+-N和单一供NO3^--N的处理分别高49.63%和63.25%.而在水分胁迫条件下,单一供NH4^+-N的处理生物量最大,比NH4^+、NO3^-混合处理和单一供NO3^--N的处理分别高5.76%和484.0%;单一供NH4^+-N其水分利用效率也最高,比NH4^+、NO3^-混合处理和单一供NO3^--N的处理分别高11.36%和81.63%,而比非水分胁迫条件下的相应处理高12.39%.此外,单一供NH4^+-N较单一供NO3^--N的处理水稻有较强的抗旱性,主要与其能保持相对较高的叶绿素含量、叶面积、分蘖数和净光合速率有关.
By using nutrient solution culture and simulated water stress by PEG(6000), the effects of different nitrogen forms (NO3^-N, NH4^+ -N and the mixture of NO3^- -N and NH4^+ -N) and water statuses ( non-water stress and water stress ) on water use efficiency (WUE) and the biological characteristics of rice plants at seedling-tillering stage were studied. The results showed that, under non-water stress, the biomass of rice plants were about 49.63 % and 63.25 % higher under the supply of mixture of NO3^- -N and NH4^+ -N than either sole supply of NO3^- -N or NH4^+ -N, respectively. However, under water stress, the biomass of rice plants were about 5.76% and 484.01% higher under sole ammonium supply than the other two treatments, WUE of rice plants were also 11.36% and 81.63% higher than the two treatments, while 12.39% higher than the same nitrogen form supply under non-water stress. Furthermore, rice plants grown with ammonium nutrition showed a stronger tolerance to water stress, due to their higher chlorophyll content, leaves area, tillers, and net photosynthetic rate et al. compared with those grown with nitrate nutrition.