Abstract: In order to explore the effects of colchicine treatment on the seed germination and seedling growth of broccoli, this experiment took broccoli seeds as materials, soaked with different concentrations of colchicine（0.03%, 0.05%, 0.07%, 0.10%, 0.20%, 0.30%）for different time（12, 24 h）, and compared with the seed soaking treatment in distilled water（CK）. The effects of colchicine treatment on the seed germination, seedling morphological, physiological and biochemical characteristics of broccoli were studied. The results showed that compared with CK, there was no significant difference in germination rate and germination potential among the treatment groups after soaking for 12 h, and the vitality index of 0.20% and 0.30% colchicine trearment groups increased significantly. After soaking for 24 h, all germination indexes decreased in all treatment groups. 0.10%-0.30% colchicine treatment increased the fresh weight and stem thickness of broccoli seedlings, decreased plant height, leaf length and width, increased the antioxidant enzyme（SOD, CAT）activities, osmoregulatory substances and glucosinolates content, while decreased the malondialdehyde content. According to the analysis of membership functions of the measurement indicators of broccoli, the average membership function values of 0.30% colchicine soaking for 12 and 24 h ranked first. In a comprehensive analysis, 0.30% colchicine soaking for 12 h was considered as the best treatment combination to promote seed germination and seedling growth of broccoli.

Key words: broccoli, colchicine, seed germination, membership function analysis