大白菜幼苗春化对低温、光照和苗龄的要求

The Low Temperature,Light and Seedling Age Requirement for Seedling Vernalization in Chinese Cabbage

以不同冬性的6个大白菜品种为试材,研究了幼苗在4～5℃低温下分别处理0、8、15、22、29、36、43d后的现蕾开花情况。结果表明:不同品种幼苗春化对低温的需求不同,冬性弱的品种需要较短的低温过程,冬性强的品种需要较长的低温过程,其范围从8到29d以上;随着春化时间的延长,不同冬性品种都表现开始现蕾的时间提前,全部现蕾需要的持续时间缩短,即向现蕾早而集中发展。在黑暗条件下连续低温处理29d的幼苗没有现蕾,说明光照对幼苗通过春化是必需的。不同冬性的大白菜不同幼苗于4～5℃下春化25d后观察,4～5叶期幼苗对低温最敏感,2～3叶期的次之,7～8叶期最不敏感,其中冬性弱的品种开始现蕾的时间以4～5叶期现蕾最早,2～3叶期的次之,7～8叶期最晚;不同冬性品种完全现蕾的持续时间以4～5叶期持续时间为最少,2～3叶期的次之,7～8叶期持续时间最长。

The seedlings of six varieties of Chinese cabbage with different coldness were treated at low temperature for 0, 8, 15, 22, 29, 36, 43 d, respectively, the time of bud emerging were investigated and compared, the results showed that the requirement of low temperature treatment days for vernalization is dependented on the coldness of variety, the weaker of coldness, the shorter of low temperature treatment is needed, the requirement range is from 8 days to more than 29 days respectively. As the low temperature treatment days is increased, the floral bud is emerging earlier, the duration for all plant emerging bud is shorted. It was found that the light during low temperature treatment is needed for vernalization, the plant do not pro- duce floral buds even treated for 29 d under dark condition. When the different coldness varieties with different seedling age were treated at 4 -5℃ for 25 days, it was found （hat the sensitivity to low temperature for vernalization is 4 - 5 leaves seedling 〉 2 - 3 leaves seedling 〉 7 - 8 leaves seedling, such as the time of bud emerging is earliest in 4 - 5 leaves seedling, latest in 7 - 8 leaves seedling for weaker coldness varieties, and the days for all plant producing bud is shortest in 4 - 5 leaves seedling, and longest in 7 - 8 leaves seedling for all various coldness varieties.