氮肥形态对李氏禾富集铬的影响及其生化分析

Effect of Nitrogen Forms on Cr Uptake by the Leersia hexandra Swartz and Biochemical Analysis

通过盆栽试验研究了在土壤铬含量分别为100、400 mg/kg时,不同氮肥((NH4)2SO4、NH4NO3、Ca(NO3)2)对Cr超富集植物李氏禾生长和Cr积累的影响。结果表明:在土壤铬含量为400 mg/kg时,用(NH4)2SO4处理后李氏禾的根、茎和叶中的铬浓度最大,分别达到19 546、3 265、6 118 mg/kg,约为对照处理铬含量的1.5～4倍。NH4NO3处理的李氏禾生物量相对其他处理及对照较高;两种铬浓度处理的土壤中,施加(NH4)2SO4、Ca(NO3)2及对照处理,生物量差异性均不显著。不同氮肥处理中,在400 mg/kg铬处理土壤上生长的李氏禾总糖都多于100 mg/kg铬处理;而NH4NO3处理的李氏禾蛋白质和叶绿素高于其他处理。NH4NO3能提高李氏禾生长速度,总糖浓度的增加能提高李氏禾对逆境的适应机制。

The effect of nitrogen forms on the growth and uptake of Cr by hyperaccumulator Leersia hexandra Swartz in soil is tested with 100 and 400 mg/kg Cr concentration in pot experiments.The results indicate that the maximum chromium concentration in the dry root,stem and leaf of Leersia hexandra by（NH_4）_2SO_4 reaches 19 546,3 265,6 118 mg/kg.When the Cr concentration of soil is 400 mg/kg,they are 1.5 to 4 times the weight of the CK.A higher biomass is obtained when nitrogen is supplied as NH_4NO_3.Biomass difference is not significant in the experiment with（NH_4）_2SO_4,Ca（NO_3）_2 and CK,regardless whether soil applied with 400 mg/kg Cr or not.Sugar in plants with 400 mg/kg is more than that of 100 mg/kg among（NH_4）_2SO_4,NH_4NO_3 and Ca（NO_3）_2.But the chlorophyll and protein contents are highest when applied with NH_4NO_3.The results show that nitrogen supplied with NH_4NO_3 promotes growth best,and higher concentration of soluble sugar can possibly provide an adaptive mechanism under adverse circumstances.