Abstract: The effects of CrCl₃ stress with different concentrations on some earlier physiological and ecological responses of seed germination,and correlation between physiological index and the contents of Cr³⁺ absorption of Zea mays were studied.The results showed that seed germination rate,plant height,root length,fresh weight and dry biomass of seedlings gradually decreased with increasing CrCl₃ concentrations.While not only the contents of proline,soluble protein,chromium and malonaldehydic acid (MDA) increased,but the activity of superoxide dismutase (SOD),peroxidese (POD) and catalase (CAT)increased gradually.But the diffrence of root vigor and activity of nitrate reductase (NR) evidently varied among different variety.The positive correlation between Cr³⁺ content and MDA contents,SOD and CAT activity was significant at the 0.01 level or 0.05 level.In a word,different Zea mays variety tend to have different responses to Cr³⁺ toxicity,there are differences among variety.

Key words: Loess Plateau, Soil moisture content, Spatial he terogeneity, Dominant controls, Profile pattern, Temporal dynamics