Sangwan Punesh, Kumar Vinod, Joshi U N
Department of Biochemistry, CCS Haryana Agricultural University, Hisar 125001, India.
Department of Biochemistry, G. B. Pant University of Agriculture and Technology, Pantnagar 263145, India.
Enzyme Res. 2014;2014:784036. doi: 10.1155/2014/784036. Epub 2014 Mar 18.
Heavy metals are the intrinsic component of the environment with both essential and nonessential types. Their excessive levels pose a threat to plant growth and yield. Also, some heavy metals are toxic to plants even at very low concentrations. The present investigation (a pot experiment) was conducted to determine the affects of varying chromium(VI) levels (0.0, 0.5, 1.0, 2.0, and 4.0 mg chromium(VI) kg(-1) soil in the form of potassium dichromate) on the key enzymes of nitrogen metabolism in clusterbean. Chromium treatment adversely affect nitrogenase, nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate dehydrogenase in various plant organs at different growth stages as specific enzyme activity of these enzymes decreased with an increase in chromium(VI) levels from 0 to 2.0 mg chromium(VI) kg(-1) soil and 4.0 mg chromium(VI) kg(-1) soil was found to be lethal to clusterbean plants. In general, the enzyme activity increased with advancement of growth to reach maximum at flowering stage and thereafter decreased at grain filling stage.
重金属是环境的固有组成部分，有必需和非必需类型。其过量水平对植物生长和产量构成威胁。此外，一些重金属即使在极低浓度下也对植物有毒。本研究（盆栽试验）旨在确定不同铬（VI）水平（以重铬酸钾形式存在，土壤中铬（VI）含量分别为0.0、0.5、1.0、2.0和4.0毫克/千克）对瓜尔豆氮代谢关键酶的影响。铬处理对不同生长阶段各植物器官中的固氮酶、硝酸还原酶、亚硝酸还原酶、谷氨酰胺合成酶和谷氨酸脱氢酶产生不利影响，因为随着土壤中铬（VI）含量从0增加到2.0毫克/千克，这些酶的比酶活性降低，且发现4.0毫克/千克铬（VI）的土壤对瓜尔豆植株具有致死性。总体而言，酶活性随着生长进程增加，在开花期达到最大值，随后在灌浆期下降。
