| 【Objective】The polyethylene glycol 6000（PEG6000）solution was used to simulate drought stress to study the root morphological characteristics, physiological and biochemical characteristics of the seedlings of spring rapeseed（Brassica campestris L.）at bud stage, and evaluate the drought resistance of different spring rapeseed cultivars（lines）.【Method】Different concentrations（0%, 5%, 10%, 15%, 20%, 25%）of PEG6000 solutions were used to the study the effect of drought stress on the growth, physiological and biochemical characteristics of four spring cultivates（lines）rapeseed seedlings. Meanwhile, the drought resistant spring rapeseed cultivars（lines）were screened out.【Result】PEG6000 solutions had significant inhibitory effects on the seedling rate, main root length, seedling height, fresh quality per plant and relative vigor index of four spring rapeseed cultivars（lines）at bud stage. When the PEG6000 solution concentration was in the range of 15%-20%, the relative vigor index of spring rapeseed of four cultivars（lines）was 0.50-0.60. When the PEG6000 concentration was 0%-15%, the activity of superoxide dismutase（SOD）, peroxidase（POD）and catalase（CAT）were positively correlated with the stress mass fraction. The enzyme activity reached the peak when the PEG6000 concentration was 15%-20%, and then decreased. In the low stress concentration range（5%-15%）, soluble sugar（SS）, soluble protein（SPr）, proline（Pro）, malondialdehyde（MDA）were positively correlated with PEG6000 solution concentration.【Conclusion】The relative vigor index and seedling height of spring rapeseed could be used as drought resistance screening indicators, and 15%-20% PEG6000 solution concentration as the optimum concentration to simulate drought stress for spring rapeseed. And the drought resistance line 104005 was selected. |
