谷氨酸对烤烟氮素营养贡献及生理特性研究

Research on Contribution of Glutamic Acid to Nitrogen Nutritionand Physiological Characteristics of Flue-Cured Tobacco

为探究氨基酸态氮对烤烟生长及氮素营养贡献的影响,以南江三号为试验材料,以L-谷氨酸(Glu)为有机氮源,^(15)NH_(4)^(15)NO_(3)为无机氮源,设置不同氮源配比的5个处理:不施氮(CK)、100%无机氮(T1)、25%谷氨酸态氮+75%无机氮(T2)、50%谷氨酸态氮+50%无机氮(T3)、75%谷氨酸态氮+25%无机氮(T4)和100%谷氨酸态氮(T5),测定烟株生物量、氮含量及相关酶的活性。结果表明,施用谷氨酸对生育前期烟株的生物量及氮素含量均有一定的抑制作用,团棵期抑制效果最明显;生育后期,25%~50%的氨基酸能促进烟株的生长;随谷氨酸比重的增加,上、中部烟叶全氮占比有不同程度的增加,而下部烟叶全氮占比从16.77%到8.03%逐渐降低,施用谷氨酸有利于烟株中、上部烟叶氮素含量的积累;烟株根、茎、叶的谷丙转氨酶和谷氨酸脱氢酶活性均随谷氨酸占比的增加呈增长趋势。可见,烤烟可以直接吸收且利用谷氨酸分子,低浓度谷氨酸与无机氮配施能促进烟株的生长,调节烟株体内氮素的分布,但高浓度谷氨酸则对烟株的生长起抑制作用。

In order to explore the effects of amino acid nitrogen on the growth and development of flue-cured tobacco and the contribution of nitrogen nutrition,using Nanjiang No.3 as the material,L-glutamic acid as the organic nitrogen source,^(15)NH_(4)^(15)NO_(3) as the inorganic nitrogen source,five treatments with different nitrogen source ratios were set up:no nitrogen application(CK),100%inorganic nitrogen(T1),25%glutamate nitrogen+75%inorganic nitrogen(T2),50%glutamate nitrogen+50%inorganic nitrogen(T3),75%glutamate nitrogen+25%inorganic nitrogen(T4),100%glutamate nitrogen(T5),and the tobacco plant biomass,nitrogen content and related enzyme activities were measured.The results showed that,the application of glutamic acid had a certain inhibitory effects on the biomass and nitrogen content of tobacco plants in the early growth period,and the most obvious inhibitory effects was at the rosette stage.In the later growth period,25%-50%of amino acids could promote the growth of tobacco plants.With the increased of the proportion of glutamate,the proportion of total nitrogen content in the upper and middle tobacco leaves increased with different degrees,while the proportion of total nitrogen in the lower tobacco leaves gradually decreased from 16.77%to 8.03%,the application of glutamate was conducive to the accumulation of nitrogen content in the middle and upper leaves of the tobacco plant.The activities of GPT and GDH of plant roots,stems and leaves showed an increasing trend with the increase of the proportion of glutamate.It showed that,flue-cured tobacco could directly absorb and utilize glutamate molecules.The combination of low-concentration glutamate and inorganic nitrogen could promote the growth of tobacco plants and regulate the distribution of nitrogen in tobacco plants.However,high concentrations of glutamate inhibited the growth of tobacco plants.