干旱胁迫下柱花草种子的萌发特性

Seed germination characteristics of Stybsanthes guianensis cv.under different drought stress

【目的】探讨不同干旱胁迫强度对柱花草种子萌发的影响,为其高产栽培提供参考。【方法】用不同浓度的聚乙二醇(PEG-6000)模拟干旱胁迫,测定干旱胁迫下柱花草种子发芽率、平均发芽速度、胚芽和胚根长度及发芽指数、活力指数等指标。【结果】在5%PEG-6000处理下,907柱花草种子发芽率及发芽势达到最高,均为37.5%,比对照高10.42%(绝对值);发芽指数为7.25,比对照高0.95;随着PEG-6000浓度的增加,柱花草种子的发芽率、发芽指数和活力指数均呈明显下降趋势。随着干旱胁迫程度的增加,延缓了柱花草种子萌发时间,不同处理的种子萌发时间表现为对照CK<5%处理=10%处理<15%处理;种子的发芽高峰期推迟,对照CK在第4 d达到日相对发芽率的高峰(12.5%),比5%、10%、15%PEG-6000处理分别提前1、2、2 d;柱花草幼苗胚根和胚芽长、生物产量不断减少,种子抗旱指数与萌发抗旱指数不断降低。【结论】柱花草具有一定抗旱能力,轻度干旱胁迫对其种子萌发具有一定促进作用,中、高度干旱胁迫抑制柱花草幼苗生长。

【Objective】Seed germination of Stybsanthes guianensis cv. under different drought stress was studied to provide references for high-yield cultivation. 【Method】Seed germination rate,average speed of germination, length of radicle and hypocotyls,germination index and viability index were measured in different drought stress simulated by different concentrations of polyethylene glycol （PEG-6000）. 【Result】Under 5% PEG-6000, 907 germination rate and potential reached the highest （37.5%）, which was 10.42% higher than the control. （absolute value）Its germination index was 7.25, 0.95 higher than the control. More PEG-6000 made the germination rate, germination index and viability index down evidently. More stress extended the germination and fastigium time. Seed germination time equation was CK〈5% treatment=10% treatment〈15% treatment. The control hit the germination peak on 4 d （12.5%）, which was 1, 2 and 2 d ahead of 5%, 10% and 15% PEG-6000. Length of radicle and hypocotyls and biomass were reduced constantly. Seed anti-drought and germination index were on the downside. 【Conclusion】Stybsanthes guianensis cv. could stand drought to some extent. Little drought actually promoted its germination, while moderate and high level drought inhibited.