短时高温处理对4种松树种子萌发的影响

摘要

In this study,we investigated the seed germination and tolerances to high temperature of four pinus species(Pinus yunnanensis,P.kesiya var.langbianensis,P.densata and P.massoniana) under laboratory condition after different high temperature treatments(60、90、120 and 150 ℃)and time treatments(1、5 and 10 min).Another group of seeds of each species were not heated and consid-ered as a control.The results showed that:1)when the temperature was up to 60℃,the P.yunnanen-sis seed germination rate was higher than normal control group significantly,and the thermal shock effects was apparent;2)When the temperature was below 120 ℃,regardless of how much processed time,the treatments could promote the seed germination rate of P.densata and P.massoniana signifi-cantly,with thermal shock effects;3)Short-term heating pretreatment had no significant effect on seed germination rate of P.kesiya var.langbianensis;4)P.yunnanensis and P.densata had strong tolerances to high temperature and could endure temperatures greater than 120 ℃ and 10 min expo-sure;5)However,temperature up to 150 ℃ and higher than 5 min exposure showed lethal effects on the percentage germination of four kinds pinus species seeds.The thermal shock effect and tolerances to high temperature of seeds are related to the fire regime in pine distribution area.%以云南松、思茅松、高山松和马尾松4种松树种子为试验材料,萌发前对种子进行不同温度(60,90,120 ℃和150℃)和时间(1,5 min和10 min)的处理,以常温为对照,研究萌发前短时高温处理对种子萌发的影响以及4种松树种子的耐高温能力.结果表明:1)当处理温度为60 ℃时,云南松种子的萌发率显著高于对照组,具有明显的热冲击效应;2)当处理温度低于120 ℃时,无论处理时间为几分钟,对高山松和马尾松种子的萌发均具有显著的促进作用,具有热冲击效应;3)短时高温处理对思茅松种子的萌发率无显著性影响;4)云南松和高山松种子都具有较强的耐高温能力,当温度高达120 ℃、处理10 min时,还具有一定的萌发能力;5)当处理温度为150 ℃、处理时间≥5 min时,4种松树的种子均不萌发.种子的热冲击效应和耐高温能力与松树分布区火发生的状态有关.