萌发前高温处理对黄茅种子萌发率的影响

Effects of High Temperature Treatment Before Germination on Seed Germination Rate of Heteropogon contortus

高温可促进许多物种的种子萌发。以中国西南干热河谷代表物种黄茅(Heteropogon contortus)种子为实验材料,在萌发前用60℃(10,20,40min)、80℃(5,10,20min)、100℃(2.5,5,10min)不同温度和时间处理后观测种子萌发率,以常温(25℃左右)为对照,采用方差分析和多重比较的方法,研究萌发前高温处理对黄茅种子萌发率的影响,以探讨火对干热河谷植物适应性的影响。结果表明:1)当处理温度为60℃和80℃时,黄茅种子的萌发率高于常温对照组,80℃20min处理的萌发率最高,为(85±4.12)%,具有明显的热冲击效应;2)60,80℃以及100℃2.5min处理对黄茅种子萌发有显著促进作用;100℃5,10min的处理,对种子萌发有明显抑制作用,萌发率呈现先升后降的趋势;3)经60℃10,20,40min和80℃5,10,20min以及100℃2.5min处理后,其萌发势高于对照组,明显缩短了种子萌发时间;4)100℃5,10min处理的黄茅种子活力较低,但仍然具有一定的萌发能力;5)黄茅种子萌发时间集中在前1周,后续虽有萌发,但萌发率较低。研究表明,萌发前高温处理可促进黄茅种子萌发,具有明显的热冲击效应。

High temperatures can promote seed germination in many species.This experiment chose Heteropogon contortus seeds that the one of dominant species in the dry-hot valleys in Southwest China as the test materials.In this experiment,the H.contortus seeds before germination were treated at the different temperatures and time of 60℃(10,20,40 min),80℃(5,10,20 min)and 100℃(2.5,5,10 min)for reference,together with a group of seeds treated under 25℃or so as a control,adopting the method of variance analysis and multiple comparison,the effects of high temperature before germination on the germination rate of seeds were studied to explore the effects of fire on the adaptability of plants in dry hot river valley.The results showed that:1)when the processing temperature was up to 60℃and 80℃,the germination rate of H.contortus seeds was significantly higher than that of the normal control group and the germination rate was the highest at 80℃for 20 min treatment,that was(85±4.12)%,it had the obvious thermal shock effect;2)The seeds significantly promoted when the seeds treatments of H.contortus were at 60℃,80℃and 100℃for 2.5 min,while at 100℃for 5 and 10 min,the germination rate had obvious inhibitory effect on seed germination and showed a tendency to increase first and then decrease.3)The germination potential of the seeds was higher than that of the control group at 60℃for 10,20,40 min and 80℃for 5,10,20 min and 100℃for 2.5 min after treatment and the seed germination time was shortened obviously.4)When the treatment was at 100℃for 5,10 min,the seed vigor of H.contortus was lower but still had some germination ability.5)The seed germination time of H.contortus was concentrated in the previous week,although there was germination,the germination rate was low.Thus,we drew a conclusion that the high temperature treatment before germination could promote the germination of the H.contortus seeds and had apparent heat shock effects.