【摘要】 采用常规耗竭法和改进耗竭法研究冷凉条件下山荆子(Malus baccata Borkh.)幼苗根系吸收不同形态氮素动力学特征。结果表明,温度影响山荆子氮素吸收动力学特征,常温(25℃)时山荆子根系载体蛋白对NO3-离子的亲和力大于NH4+离子,此时根系优先吸收NO3-离子;冷凉(10℃)条件下山荆子幼苗对NH4+离子的亲和力大于NO3-离子,此时根系优先吸收NH4+离子。冷凉条件降低了山荆子幼苗对NO3-和NH4+的吸收能力,表现为最大吸收速率(Imax降低)、养分流入根系速率(α值降低)和亲和力下降(Km值增加),其中对吸收NO3-离子的影响大于NH4+离子。更多还原

【Abstract】 The method of conventional exhaustion and improved exhaustion was carried out to study the kinetics characteristics of nitrogen absorption in root of Malus baccata Borkh.seedlings in cool and cold conditions.The characteristics of nitrogen absorption kinetics were affected by cool and cold condition.In normal temperature(25 ℃)the affinity of NO3-was greater than that of NH4+ which indicated that root had the priority to absorb NO3-.But in cool and cold condition(10 ℃)the affinity of NH4+ was greater than that of NO3-,and in this moment the root had the priority to absorb NH4+.The M.baccata Borkh.seedlings’ absorption was decreased in cool and cold condition and it was indicated that the maximum absorption velocity,nutrient inflow velocity and affinity of NO3-and NH4+ were decreased in cool and cold condition.The influence of cool and cold condition in absorbing NO3-was greater than absorbing NH4+.更多还原