水分胁迫下苹果幼苗超弱发光及一些生理特性的变化

以苹果属八棱海棠和平邑田茶当年实生幼苗为试材，研究了在用15％ PEG 6000溶液模拟干旱处理条件下幼苗的超弱发光(ultraweak luminescence，UWL)及ATP含量、呼吸与活性氧(O2^-)产生速率等一些生理特性的变化。结果表明，随水分胁迫时间的延长，幼苗的UWL、ATP含量、蛋白质含量均呈下降趋势，呼吸速率先升后降，而丙二醛(MDA)含量与O2^-的产生速率呈明显上升趋势。品种间各指标比较表明，八棱海棠比平邑田茶具有较强的抗水分胁迫能力，UWL反映幼苗品种抗旱性结果与用其它生理指标测定的结果一致。分析认为，幼苗UWL强度没有随胁迫下氧自由基的增加而增加，说明活性氧不是导致UWL的唯一原因。苹果幼苗UWL的变化是受环境及体内代谢等多种因素的影响，并且与其自身的生长与代谢活性更密切。

Changes of ultraweak luminescence and some physiological characters of apple seedlings under water stress

Annual apple seedlings of Malus micromalus Makin and M.hupehensis (Pamp.) Rehd. were used to study the changes of UWL intensity,contents of ATP and protein,respiration rate,production rate of active oxygen and some other physiological characters under water stress on the treatment with 15% PEG6000.The results showed that the UWL intensity,contents of ATP and protein decreased while the production rate of active oxygen and malondialdehyde (MDA) content increased distinctly and the respiration rate increased at first and then decreased with the prolongation of water stress time.The indexes of the two apple seedlings indicated that the drought resistance of Malus micromalus was higher than that of M.hupehensis .And the drought resistance reflected by UWL and other physiological characters were consistent.It was concluded that the UWL intensity was closely related to the growth and metabolism activity of apple seedlings and the active oxygen was not the only factor to lead to the rise of UWL.