热激对大兴安岭三种松科树种种子萌发的影响

摘要

研究了热激对大兴安岭地区兴安落叶松、樟子松、红皮云杉种子萌发的影响,热激温度分别为80℃、100℃、120℃、150℃,每个温度下热激时间分别为1 min、3min、5min、10min.研究结果表明:兴安落叶松种子在100℃热激10min,120℃热激5min,10min,150℃热激5min处理下萌发率较对照显著下降(P＜0.05),除80℃热激1min、3min、5min、120℃热激1min、150℃热激1min外,其他处理萌发速率指数较对照均显著下降(P＜0.05);樟子松种子在高于80℃的所有热激处理萌发率较对照均显著下降(P＜0.05),甚至没有萌发,除80℃热激1min外,所有处理下萌发速率指数较对照均显著下降;红皮云杉种子萌发率在80℃热激5min和100℃热激1min处理下较对照显著提高(P＜0.05),萌发速率指数在80℃热激1min、3min、5min,100℃热激1min处理下较对照显著提高(P＜0.05).兴安落叶松种子可以在短时间高强度(150℃)热激下维持萌发率,但不能承受长时间热激;樟子松种子对高于80℃的热激反应敏感,热激降低了樟子松种子的萌发能力;热激可以提高红皮云杉种子的萌发能力,短时间(1min、3min、5min)低强度(80℃)热激(包括100℃热激1min)提高红皮云杉种子萌发率和萌发速率指数,红皮云杉种子也可以承受高强度(150℃)瞬时(1min)热激.%This study examines the effect of heat shock on the seed germination of Larix gmelinii,Pinus sylvestris var.mongolica and Picea koraiensis from a fire-prone forest in the Great Hing'an Mountains.Seeds of the three species were exposed to a range of temperatures (80,100,120,and 150 ℃) for different exposure times (1,3,5 and 10 min).The results show that the germination rate of Larix gmelinii seeds decreased significantly (P ＜ 0.05) relative to the control when seeds were subjected to 100℃ for 10min,120℃ for 5min and 10min,and 150℃ for 5min.With the exception of exposures at 80℃ for 1,3 and 5 min;120℃ for 1min;and 150℃ for 1min,the germination velocity index of Larix gmelinii seeds showed a significant(P ＜ 0.05) decrease for all other heat shock treatments.For sylvestris var.mongolica,the germination rate subsequent to all heat shock treatments above 80℃ decreased significantly (P ＜ 0.05)relative to the control.Even to the point where no germination occurred at all.At the same time,the germination velocity index for every heat shock treatment higher than 80℃ decreased significantly at 1min exposure.For Picea koraiensis,the germination rate increased significantly (P ＜ 0.05) relative to the control when subjected to heat shock treatments of 80℃ for 5min and 100℃ for 1 min.Moreover,the germination velocity index increased significantly(P ＜ 0.05)for heat shock treatments of 80℃ for 1,3,and 5min and 100℃ for 1min.On an overall basis,Larix gmelinii seeds was able to maintain standard germination rate after a transitory high intensity heat shock of 150℃;however,it cannot tolerate a longer heat shock,the influence of transitory high intensity heat on the germination rate was more significant than that on the germination velocity index.Pinus sylvestris var.mongotica seeds were quite sensitive to a heat shock above 80℃:the germination rate sharply decreased with a 100℃ heat shock and almost no seeds germinated above 100℃.Picea koraiensis seeds are capable of tolerating an instantaneous (1min) high intense heat shock (150℃),and a light heat shock over short time periods(1min,3min,5min)for 80℃ (100℃ for 1 min included) stimulated seed germination of Picea koraiensis.