砷污染土壤中施用黄腐酸对烤烟(Nicotiana tabacum L.)氮代谢的影响

Effect on nitrogen metabolism of flue-cured tobacco(Nicotiana tabacumL.)in fulvic acid applied to arsenic-contaminated soil

采用盆栽试验,研究砷污染土壤中施用黄腐酸(FA)对烤烟氮代谢及其过程的影响。结果表明,与砷污染土壤相比,施用黄腐酸提高了烤烟的硝酸还原酶(NR)活性,降低了谷氨酰胺合成酶(GS)活性,改善了NO3--N的同化能力,抑制了NH4+-N的同化。不同FA施用量对氮转化代谢的影响不同,在团棵期,虽然黄腐酸的施用提高了谷氨酸-丙酮酸转氨酶(GPT)活性,但随着生育进程的推进,适量的黄腐酸最终能抑制氮转化代谢的旺盛问题,使谷氨酸-丙酮酸转氨酶(GPT)、天冬酰胺酶(ASG)活性和游离氨基酸含量降低。砷污染土壤中施用黄腐酸还可降低烤烟团棵期的蛋白质含量,提高现蕾以后的蛋白质含量和全生育期的烟碱含量。本试验条件下,以土壤中施用600mg/kg的FA对减轻砷毒害效果最好。

A systematic experiment was conducted on the farm of Henan Agricultural University,Zhengzhou,China.Using Yunyan 85 planted in 400mm×340mm plastic pots,treatments were layed out with 5levels of 0（CK）,200,400,600 and 800mg/kg（added as fulvic acid）in soil with 50mg/kg sodium arsenate（Na3AsO4·12H2O）,respectively,to determine the effect on nitrogen metabolism of flue-cured tobacco in fulvic acid applied to arsenic-contaminated soil.The results showed that different contents of fulvic acid had different effects on nitrogen metabolism of flue-cured tobacco.Although activity of glutamate-pyruvate transaminase（GPT）was increased in fulvic acid applied to arseniccontaminated soil in the rosette stage,but finally improved NO3--N assimilation and inhibited NH4＋-N assimilation.Reasonable content of fulvic acid decreased in free amino acids content,and in activity of glutamate-pyruvate transaminase（GPT）and asparaginase（ASG）,which finally improved transformation of nitrogen of flue-cured tobacco.Fulvic acid increased protein content after budding stage and nicotine content during the whole growing period,but decreased protein content at rosette stage.The best treatment in this experiment was that applied 600mg/kg of fulvic acid to arsenic-contaminated soil.