中文摘要：

Malus 的三种的幼苗被用来响应水应力学习激活 mitogen 的蛋白质 kinase (MAPK ) 的表示：Malus hupehensis，干旱敏感的种；Malus sieversii，干旱容忍的种；并且 Malus micromalus，一种中间的类型。结果显示出那 Malus MAPK (MaMAPK， GenBank 同意没有。AF435805 ) 在为不同时间时期与 20% 聚乙烯乙二醇对待的三 Malus 种的幼苗的根和叶子被表示。表示层次与聚乙烯乙二醇在处理以后在 1.5 h 达到顶点，然后减少了到他们的底层。液体 kinase 试金显示 MAPK 活动的动态变化很类似于 MaMAPK mRNA 的相对表示的那些。然而，前者的山峰在后者后面稍微发生了。尽管 kinase 活动在山峰以后减少了，它仍然比控制的高在期间，这被注意自始至终时期。这些结果建议 MaMAPK 不仅走水路被调整在抄写水平强调，而且由在蛋白质的 phosphorylation 和 dephosphorylation 铺平。另外，这，三苹果种，最高的 MAPK 活动和 MaMAPK 表示水平在 M 被发现。sieversii，由 M 列在后面。micromalus 和 M。hupehensis，建议那 MAPK 可能在这与干旱忍耐被相关三种。不同表示层次可能是在 Malus 的不同干旱忍耐的分子的机制之一。

英文摘要：

Seedlings of three species of Malus were used to study the expression of mitogen-activated protein kinase （MAPK） in response to water stress： Malus hupehensis, a drought-sensitive species; Malus sieversii, a drought-tolerant species; and Malus micromalus, a middle type. Results showed that Malus MAPK （MaMAPK, GenBank accession No. AF435805） was expressed in both roots and leaves of seedlings of the three Malus species treated with 20% polyethylene glycol for different time periods. Expression levels peaked at 1.5 h after treatment with polyethylene glycol, then decreased to their lowest levels. Liquid kinase assays indicated that the dynamic changes of MAPK activity were very similar to those of the relative expression of MaMAPK mRNA. However, the peak of the former occurred slightly behind the latter. It was noticed that, although the kinase activity decreased after the peak, it was still higher than that of the control during the whole time period. These results suggested that MaMAPK was regulated not only by water stress at the transcription level, but also by phosphorylation and dephosphorylation at the protein level. In addition, of these three apple species, the highest MAPK activity and MaMAPK expression level was found in M. sieversii, followed by M. micromalus and M. hupehensis, suggesting that MAPK might be correlated with drought tolerance in these three species. The different expression levels might be one of the molecular mechanisms of the different drought tolerances in Malus.