干旱胁迫对新疆野苹果及平邑甜茶生理生化特性的影响

The Physiology and Biochemistry of Programmed Malus siversii and M. hupehensis Cell Death under Drought Stress

【目的】研究干旱胁迫能否诱导新疆野苹果和平邑甜茶发生细胞程序性死亡。【方法】采用20%聚乙二醇(PEG6000)模拟干旱处理苹果属植物平邑甜茶(Malus hupehensis pamp Reld.)和新疆野苹果(M.sieversii(Ledeb)Roem.)。【结果】NBT染色结果表明,平邑甜茶叶片在处理1d后开始有染色斑出现,4d后叶片几乎被全部染色;新疆野苹果叶片在处理3d后开始有染色斑出现,7d后叶片几乎被全部染色。叶片萎蔫情况观察可以看出:平邑甜茶在处理3d后开始萎蔫,4d后叶片干枯、整个植株死亡;新疆野苹果在处理6d后开始萎蔫,7d后整个植株死亡。两个苹果种的叶片相对电导率随处理时间的延长逐渐上升;平邑甜茶在处理3.5d后相对电导率增幅明显加大,而新疆野苹果在处理6d后才明显增大。平邑甜茶在处理后DNA和RNA含量就开始明显下降,而新疆野苹果下降速度缓慢。【结论】0.1%NBT染色、相对电导率测定、DNA含量和RNA含量测定等生理生化指标不仅可以作为鉴定苹果属植物在水分胁迫条件下发生细胞程序性死亡的指标,而且可以作为衡量苹果属植物抗旱性及衰老的参考指标。

[Objective] The object of the study was to observe the relationship between drought stress and programmed cell death. [Method] Twenty percent of polyethylene glycol（PEG6000） was used to simulate drought stress to treat the seedlings of Malus sieversii and M. hupehensis. [Result] NBT dyed reaction showed that M. sieversii leaves began appearing dyed spots 1 day after being treated. Its area expanded 4 days later, but these occurred in M. hupehensis at 1^st and 7^th day after the treatment, respectively. The seedlings of M. sieversii started to wilt at the 3^rd day after treatment and died after 4 days. Seedlings of M. hupehensis began to wilt after 6 days treatment and died on the 7^th day. The contents of DNA and RNA in leaves of M. hupehensis decreased rapidly after treatment, but it only happened in M. sieversii, 7 days after being treated. [Conclusion] Physiology and biochemistry indexes could not only identify Malus＇ programmed cell death. Instead, they measured the plants sensitivity to drought stress as well as reflected the plant resistance to drought stress and senescence in Malus.