甜瓜对不同形态氮素的吸收动力学研究

Uptake Kinetics of Different Forms of Nitrogen by Muskmelon

采用水培方法研究了甜瓜(Cucumis melo L.)对不同形态氮素(NO3-、NH4+和Gly)的吸收动力学特性,以及添加NH4+对NO3-吸收的影响。结果表明:甜瓜对不同形态氮素的吸收符合米氏方程,最大吸收速率(Vmax)和亲和力(1/Km)均表现为NO3->NH4+>Gly。NH4+的存在促进了甜瓜吸收NO3-的能力,在提高吸收速率的同时提高了离子亲和力。

Uptake kinetics of different forms of nitrogen （NO3-, NH4＋ and Gly） by muskmelon （Cucumis melo L.）, also the effect of NH4＋ to NO3- uptake, were studied under hydroponics condition. The results indicated that uptake kinetics of different forms of nitrogen by muskmelon accorded with Michaelis-Menten equation. Both the maximum uptake rate （Vmax） and the affinity （1/Kin） followed the tendency NO3-〉 NH4＋ 〉 Gly. NH4＋ improved the uptake ability of NO3- by muskmelon, with enhancing both the uptake rate and the affinity with the uptake site.