热激对大兴安岭三种松科树种种子萌发的影响

Effect of heat shock on seed germination of three Pinaceae species in Great Hing'an Mountains

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1min、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 1min. 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. mongolica 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 1min included） stimulated seed germination of Picea koraiensis.