用nature期刊的语言风格翻译以下内容成英语：实验结果表明干旱胁迫下2M、5M和7M三个不同生长阶段的丹参MDA含量显著增加。增加幅度分别为33、37和39。

The experimental results showed that under drought stress, the MDA content of Salvia miltiorrhiza at three different growth stages, 2M, 5M, and 7M, significantly increased. The increase in content was 33%, 37%, and 39%, respectively.