细胞分裂素在维持紫萍叶状体生命中的重要作用

将无根和囊的紫萍(Spirodela polyrrhiza)P143品系半叶状体分别放在含有和不含6-苄基嘌呤的培养液上于长日照条件下培养。在不含6-BA的培养液上培养4d以后，半叶状体开始失绿，光合能力降低；第12天时，半叶状体已接近死亡。但是，培养在含有6-BA的培养液上的半叶状体干重、叶绿素和可溶性蛋白质含量、希尔反应活力、核酮糖-1，5-二磷酸羧化酶/加氧酶的小亚基和其编码基因rbcS mRNA水平显著增加。这些6-BA处理过的半叶状体平均寿命可达80d，几乎等同于完整植物体上叶状体的寿命，因此提出细胞分裂素对于紫萍叶状体生物学功能的维持是必需的。

Significant Role of Cytokinins in Maintaining the Life of Fronds in Spirodela polyrrhiza

Spirodela polyrrhiza P143 half fronds without roots and pockets were cultivated on liquid medium under long day conditions with or without 6 benzyladenine(6 BA). After 4 d of cultivation on a medium without 6 BA the half fronds began to lose their chlorophyll and decrease in photosynthetic activity, and on the 12th d of cultivation these half fronds were almost dead. But when cultivated on the medium to which 6 BA was added half fronds increased significantly their dry weight, chlorophyll and soluble protein contents, capacity of Hill reaction and the levels of the ribulose 1,5 bisphosphate carboxylase/oxygenase small subunit and the rbcS mRNA encoding it. The 6 BA treated half fronds had a mean longevity of 80 d, almost the same as that of the intact fronds. Therefore, it is proposed that cytokinins are necessary for maintaining the activities of duckweed fronds.