Singh P K, Tewari R K
Soil Science Division, National Botanical Research Institute, Lucknow-226 001, India.
J Environ Biol. 2003 Jan;24(1):107-12.
Excess of cadmium (Cd) induced changes in oxidative scenario and water status of plants viz.., total water content, specific water content, water saturation deficit (WSD) and transpiration of Brassica juncea plants grown in soil pot culture. Although lower and marginal levels of excess cadmium (100 and 250 ppm) improved growth but higher levels (500 ppm) caused significant suppression. Significant accumulation of proline, an indicator of water stress, occurred at higher level of Cd. Gradual increases in activities of certain antioxidant enzymes such as catalase and peroxidase along with increased lipid peroxidation are suggestive of disturbed oxidative metabolism. Taking together, the deleterious effects of Cd and its effects on oxidative metabolism clearly indicate enhanced generation of reactive oxygen species (ROS) to be instrumental in producing toxic effects of Cd. The excess levels of Cd also decreased the concentrations of soluble protein and chlorophylls and increased the ratio of chlorophyll a/b.
镉（Cd）过量会导致植物氧化状况和水分状况发生变化，即土壤盆栽培养的芥菜植株的总含水量、比含水量、水分饱和亏缺（WSD）和蒸腾作用。虽然较低和边缘水平的过量镉（100和250 ppm）促进了生长，但较高水平（500 ppm）则导致显著抑制。脯氨酸是水分胁迫的指标，在较高镉水平下显著积累。某些抗氧化酶如过氧化氢酶和过氧化物酶的活性逐渐增加，同时脂质过氧化增加，提示氧化代谢紊乱。综合来看，镉的有害作用及其对氧化代谢的影响清楚地表明，活性氧（ROS）的生成增加是镉产生毒性作用的原因。过量的镉还降低了可溶性蛋白和叶绿素的浓度，并增加了叶绿素a/b的比值。
