6Vallee B L, Ulmer D D. Biochemical effects of mercury, cadmium and lead [ J]. Annual Review of Biochemistry, 1972, 41: 91- 128.
7Kanazawa S, Sano S, Koshiba T, et al. Changes in antioxidative in cucumber cotyledons during natural senescence: comparison with those during dark induced senescence [ J]. Physiologia Plantarum, 2000, 109(2) : 211- 216.
8Noctor G, Foyer C H. Ascorbate and glutathione: keeping active oxygen under control [ J ]. Annual Review of Plant Physiology and Plant Molecular Biology, 1998, 49: 249- 279.
9Singh T N, Aspinall D, Palag L G. Proline accumulation and varietal adaptability to drought in barley: a potential metabolic meatnre oir drought resistance[ J ]. Nature: New Biology, 1972, 236: 188-190.
