Patra Jita, Lenka Maheswar, Panda Brahma B
Genetic Toxicology Laboratory, Department of Botany, Berhampur University, Berhampur - 760007, India.
New Phytol. 1994 Sep;128(1):165-171. doi: 10.1111/j.1469-8137.1994.tb03999.x.
Races of Chloris barbata Sw. from a mercury-contaminated site in the vicinity of a chloralkali plant and from a non-contaminated site were tested for their relative tolerance to mercury, cadmium and zinc. Pre-rooted tillers of each of the races were grown in calcium nitrate solution, Ca(NO ) , 4H O, l gl with or without HgCI (0.001, 0.01, 0.05, 0.1 and mgl ), CdSO .8H O (0.05, 1.0, 2.5 and 5 mg l and ZnSO 7H O (1, 5, 10, 20 and 40 mg l ) for a period of 5 d, Metal tolerance was evaluated by the effects of the metal on root elongation. Races from the contaminated site were found to be metal-tolerant, as indicated by higher tolerance indices (TIs) than races from the non-contaminated site. Mercury and cadmium at lower concentrations and zinc at all concentrations stimulated root growth in tolerant races, resulting in a TI of more than 100%. This indicated a requirement of the metal ion for better root growth. Compared to non-tolerant races, the tolerant races exhibited higher catalase, peroxidase and acid phosphatase activities as well as higher thiol levels. The over-all study thus indicated that races of C. barbata from the mercury-contaminated site were not only tolerant to mercury but also co-tolerant to cadmium and zinc. Biochemical studies provided evidence that the tolerant races were physiologically distinct from the intolerant races.
对来自氯碱厂附近汞污染场地和未受污染场地的绿穗画眉草（Chloris barbata Sw.）种群进行了汞、镉和锌相对耐受性测试。每个种群预先生根的分蘖在含有或不含有HgCI（0.001、0.01、0.05、0.1和mg/l）、CdSO.8H O（0.05、1.0、2.5和5 mg/l）以及ZnSO 7H O（1、5、10、20和40 mg/l）的硝酸钙溶液Ca(NO ) 4H O，1 g/l中培养5天，通过金属对根伸长的影响评估金属耐受性。结果发现，来自污染场地的种群具有金属耐受性，其耐受性指数（TIs）高于来自未受污染场地的种群。较低浓度的汞和镉以及所有浓度的锌刺激了耐受性种群的根生长，导致耐受性指数超过100%。这表明金属离子对更好的根生长是必需的。与非耐受性种群相比，耐受性种群表现出更高的过氧化氢酶、过氧化物酶和酸性磷酸酶活性以及更高的硫醇水平。因此，总体研究表明，来自汞污染场地的绿穗画眉草种群不仅对汞具有耐受性，而且对镉和锌也具有共同耐受性。生化研究提供了证据，表明耐受性种群在生理上与非耐受性种群不同。
