种质及变温对羊草种子萌发的影响

针对羊草种子萌发率低的问题,对43份不同种质的羊草种子,在两种变温条件下的萌发率进行了研究,并对恒温、变温、变温时长、变温时段对羊草种子萌发率的影响进行了测试。结果表明,羊草种子萌发率受种质影响较大,不同种质的羊草种子萌发率变幅为10%~95%,差异极显著。此外,羊草种子萌发亦受温度调控,恒温条件下(16、20、22、28、37 ℃)种子萌发率均较低,变温28 ℃(12 h)/16 ℃(12 h)则显著提高了种子萌发率,增幅为50%~90%。且变温处理对种子萌发有“时间剂量累加效应”,即变温处理时间越长,萌发率提高越大。在第1、2天时变温处理的种子萌发率与恒温对照相比,达到极显著差异,且在24 h内接收低温信号的剂量时长在2~16 h,高于16 h萌发率不随时间增加,低于2 h萌发率提高不显著。此外还发现,萌发24 h之内,羊草种子对变温处理有一个敏感的“窗口期”,即8~12 h,在这个时段内变温处理对种子萌发率提高最为显著。

Effects of germplasm and changing temperature on seed germination of Leymus chinensis

To clarify the reasons for low seed germination rate, germination of 43 different germplasm lines of sheep grass was studied at constant temperatures of 16, 20, 22, 28 and 37 ℃, and under a variable temperature regime of 28 ℃ (12 h) and 16 ℃ (12 h). It was found that seed germination percentage of sheep grass differed between germplasm lines, with values ranging from 10% to 95%. Seed germination was low under constant temperature conditions, while the alternating 28 ℃/16 ℃ treatment increased the seed germination rate by 50%-90% (P<0.01). Furthermore, the longer the daily high temperature exposure, the higher germination rate was. The seed germination rate was increased very significantly (P<0.01) on 1 day or 2 days of variable temperature treatment, compared with the constant temperature control. However, on the first day of germination, variable temperature less than 2 hours cannot significantly promotes germination, and germination rate improves significantly in 8-12 hours treatments, which considers as the “window period”.