Abstract: Cabbage seeds of different vigor degree were obtained by accelerated aging. Some methods ,Including treatments of imbibition/ dryback , mannitol gibberellin ( GA) , polythyleneglyool ( PEG) , CaCl₂ , KH2PO₄ , ascorbic acid (AsA) , were were investigated to enhance the forgoing seed vigor by L9 (34) orthogonal experiment. Then the changes of cabbage seed at physiological and biochemical level , cell level and structure of tissue cells were investigated. The results indicated that : ①All the 7 methods could improve seed vigor of
cabbage. Seed vigor was significantly enhanced after seed were treated by all the best effect combination , and PEG, GA treatment was the best one , the difference between PEG, GA and others methods was significant . ②Some physiological and biochemical changes were obvious : protease , dehydrogenase , SOD , CAT and POD were reduced significantly ; relative elelctive conductivity ( REC) and the content of MDA in seed were increased
significantly. Analysis indicated that they were correlated significantly with vigor , they were the main reason of change of seed vigor , and were reliable indexes of measuring seed vigor (at physiological and biochemical level) .
③Karyotype of root tip chromosome showed that the chromosome did not change clearly before and after improving seed vigor. ④Observation on the ultrastructure of the radicle cell of cabbage seed indicated that ultrastructure
changed with seed vigor reduced , the lower seed vigor , the clearer the change. When seed vigor was improved by all kinds of methods , ultrastructure of cell would be recovered at different degree.

Key words: Cabbage seed, Seed vigor, Methods, Mechanisms