干旱胁迫对新疆野苹果及平邑甜茶生理生化特性的影响

 【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1 d后开始有染色斑出现，4 d后叶片几乎被全部染色；新疆野苹果叶片在处理3 d后开始有染色斑出现，7 d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3 d后开始萎蔫， 4 d后叶片干枯、整个植株死亡；新疆野苹果在处理6 d后开始萎蔫，7 d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3.5 d后相对电导率增幅明显加大，而新疆野苹果在处理6 d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。

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

Malus sieversii and Malus hupehensis were treated with 20% polyethylene glycol(PEG6000) . The results are followed: The contents of DNA and RNA in leaves of sieversii were decreased slower than hupehensis treated with 20%PEG6000. The ratio of dry weight to fresh weight and the relative conductivity in leaves of sieversii were increased slower than hupehensis. In the experiment of dyed reaction with 0.1%NBT, the time of dyed in leaves sieversii was later than hupehensis. Physiology and biochemistry indexes could not only to identify fruit plants’ programmed cell death but also to measure sensitivity to water stress and to reflect drought resistance and senescence of Malus as parameters.