蒙古高原野韭种子萌发对PEG模拟干旱胁迫的响应

Seed Germination of Allium Ramosum from Mongolia Plateau Under Drought Stress Simulated by PEG

采用浓度分别为0%、5%、10%、15%、20%和25%的PEG-6000溶液模拟干旱条件,测定不同干旱胁迫条件下野韭种子的日相对萌发率、发芽势、发芽指数、活力指数及上下胚轴长度等指标,研究了野韭种子萌发及幼苗生长对PEG模拟干旱胁迫的响应,探讨了经20%、25%PEG浸种预处理后种子的萌发恢复能力。结果表明:轻度水分胁迫(5%PEG浓度)与对照组相比,提前了萌发高峰、提高了种子萌发率,对种子萌发起到明显促进作用;中度水分胁迫(10%PEG浓度)显著减低了其发芽势,但未对其发芽率产生显著影响;高度水分胁迫(15%PEG浓度)显著抑制了种子萌发,延长了种子萌发时间,但种子萌发率仍是对照的80%,说明野韭具有很强的抗旱性。当重度胁迫时(20%、25%PEG浓度)野韭种子未见萌发,但在胁迫解除后遇充足水分野韭种子当天立即萌发,且种子萌发快速整齐,这是野韭种子在度过较强的干旱不良环境后一种适应性表现,也是野生植物的生存策略之一。

0% ,5% , 10% , 15% , 20% and 25% PEG-6000 solutions were used to simulate drought stressconditions for the germination of AUium Ramosum. Daily relative germination rate, germination percentage,germination potential, germination index and vigor index under each water stress were recorded. The effects ofdrought stress through PEG treatment on seed germination,and the recovery germination ability by 20% ,25%PEG solutions soaking pretreatment were studied in a series of laboratory tests. The results showed that the mildwater stress （5% PEG concentration）compared with the control group made the germination peak ahead,improved the seed germination rate, significantly promoted the seed germination. The moderate water stress（10% PEG concentration） significantly reduced the germination potential, but had no significant effects on thegermination percentage. The high water stress （15% PEG concentration） significantly inhibited the seedgermination, prolonged the seed germination time, but the germination percentage was 80% of the control, so,A. Ramosum. had strong drought resistance. When the PEG concentration was 20% or 25%, the seeds ofA. Ramosum could not germinate. When seeds had enough moisture after stress relief, they could germinateimmediately, and quickly and orderly. This is a kind of A. Ramosum. seeds have strong drought adaptation inadverse circumstances, is also one of the survival strategies of wild plants.