甘草根系吸收不同形态氮的动力学特征研究

目的探究甘草对不同形态氮素的吸收特性,为甘草合理施用氮肥提供依据。方法常规耗竭法。结果一年生和二年生甘草根系对NH4+的平均吸收速率分别为NO3-的0.93倍和1.71倍;两者均在NO3-离子溶液浓度为0.4mmol·L-1时有最大吸收速率;加入NH4+后,一年生和二年生甘草根系对NO3-离子吸收速率分别提高了12.2倍和71.1倍;一年生甘草根系对NO3-离子的平均吸收速率为二年生甘草的1.85倍,对NH4+平均吸收速率略高于二年生甘草。结论甘草对NO3-及NH4+的吸收为协同吸收,NH4+的加入可显著提高甘草根系对NO3-的吸收能力;一年生甘草幼苗对NO3-的吸收能力高于二年生甘草;适用于甘草不同生长年限的NO3-及NH4+的最佳配方比列,还需要进一步研究确定。

Study on Kinetic Characteristics of Different Forms of Absorbing Nitrogen in Root System of Glycyrrhiza uralensis

Objective To study the kinetic characteristics of nitrogen absorption in root system of Glycyrrhiza uralensis, and provide the basis for rational fertilization. Methods The method of conventional exhaustion. Results The average rate of NH4＋ absorption of annual and biennial Glycyrrhiza uralensis is respectively 0.93 and 1.71 times of NO3-. Both annual and biennial Glycyrrhiza uralensis got the maximum absorption rate when the nitrogen concentration is about 0.4mmoloL1. Adding NH4＋ into the solution, the rate of NO absorption of annual Glycyrrhiza uralensis increased by 12.2 times and biennial ones increased by 71.1 times. The average rate of NO3 absorption of anuual Glycyrrhiza uralensis root is 1.85 times than that of biennial, and the average rate of NH4＋ absorption is also slightly higher than that of biennial. Conclusion The absorption of NO3 and NH4＋ of Glycyrrhiza uralensis is synergistic absorption, and the existent of NH4＋ could boost the average rate of NO3- absorption.The ability of absorption of NO3＋of anuual Glycyrrhiza uralensis is much more powerful than that of NH4＋.The optimal formula of NO3- and NH4＋ may need more study.