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利用人工气候箱,采取耐低温发芽筛选方法,对50份二倍体甜菜种质进行低温胁迫处理,筛选出耐低温的种质12份,芽期耐冷指数≥0.76。通过苗期耐寒性鉴定发现,这12份种质的苗期耐冷能力与芽期基本一致,但个体间对低温的反应速度及持久性表现存在差异,其中,6份资源具有更强的苗期耐冷能力。试验证明,甜菜种质苗期冷害的生理临界温度为3～6℃,在该低温阈值下,耐冷性强的种质对温度变化不太敏感,而耐冷性弱的资源对温度变化较为敏感。1～2℃是甜菜冷害的发生温度,耐冷性强的资源表现为停滞生长,子叶皱缩卷曲,真叶和下胚轴出现似烫伤表现,逐渐死亡;耐冷性弱的资源受冷害症状较早出现,很快发生畸变和死亡。
Fifty diploid beet germplasms were treated with low temperature stress by artificial climate chamber and 12 low temperature resistant germplasms were screened. The cold tolerance index at the bud stage was ≥0.76. Cold tolerance identification of seedlings revealed that the cold tolerance of these 12 germplasms was basically the same as that of bud stage, but there were differences in the response rate and persistence of low temperature between individuals. Among them, 6 had stronger seedling stage Cold tolerance. The results showed that the physiologic critical temperature of the cold damage of sugar beet germination was 3 ~ 6 ℃. Under the low temperature threshold, the germplasm with high cold tolerance was not sensitive to temperature change, while the resources with weak cold tolerance were sensitive to the temperature change. 1 ~ 2 ℃ is the occurrence temperature of beet chilling injury. The resources with strong cold tolerance showed stagnant growth, cotyledon shrunk curl, burned appearance of true leaves and hypocotyls, and gradually died; the resources with weak cold tolerance were earlier affected by chilling injury Appeared, distortion and death soon occurred.