以吉农15号和吉农24号大豆(Glycine max)品种为材料, 根据植株高度平均分为下部、中下部、中部、中上部和上部5个冠层, 分析不同冠层种子百粒重、种子活力及萌发7天子叶中抗氧化酶活性和丙二醛含量的变化。结果表明, 随着植株冠层的升高, 大豆百粒重呈先略上升后逐渐下降的趋势, 上部冠层种子的百粒重最小。大豆植株下部与中下部冠层种子的发芽率和发芽势较高; 并且该两层的种子活力指数显著高于中上部与上部冠层, 种子萌发后幼苗的茎粗也显著大于中上部及上部冠层幼苗。下部与中下部冠层种子萌发时子叶中的抗氧化酶活性高于上部, 而丙二醛含量低于上部, 说明该两层的大豆种子活力高, 萌发后幼苗健壮且子叶新陈代谢旺盛, 是优选良种的最佳冠层。

Jinong 15 and Jinong 24 were divided into 5 canopies by plant height—lower, lower-middle, middle, up- per-middle and upper—for analyzing 100-seed weight, seed vigor, changes in antioxidant enzyme activities and MDA content with germination for 7 d in different canopies of soybean cotyledon. Soybean 100-seed weight increased slightly and then decreased gradually with increasing canopy, with the upper ones being the lightest. The germination rate and germination potential were higher in the low and lower-middle heights, and their vigor indexes were significantly higher than in the upper-middle and upper heights. The stem diameter of seed germination seedlings were significantly greater in the lower and lower-middle heights than in the upper-middle and upper heights. The antioxidant enzyme activities of the cotyledon during seed germination were higher in the lower and lower-middle heights than the upper height, but the MDA content was less than in the upper height. The low and lower-middle part was the best canopy because the seed vigor was high, seedlings were robust, and cotyledon metabolism was vigorous.