Abstract:

Established switchgrass stands are very resilient to the environmental fluctuations, however, seed dormancy and low germination percentage make establishment difficult. The present study investigated the response of seed germination characteristics of switchgrass to the different plant exogenous growth substances. With the distilled water as control, switchgrass seeds were treated with different concentrations (10, 50, 200, 400, 1 000 μmol·L^-1) of abscisic acid (ABA), gibberellin (GA₃,GA₄₊₇), Indole-3-acetic acid (IAA), 6-benzylaminopurine (6-BA), fluridone (FL), and paclobutrazol (PA), respectively. The results showed that:10~200 μmol·L^-1 IAA and GA₄₊₇, 10~50 μmol·L^-1 GA₃, 50 μmol·L^-1 6-BA and 10 μmol·L^-1 FL significantly improved the seed germination of switchgrass (P<0.05) which was inhibited at high concentrations. ABA inhibited the seed germination while PA had no significant effect on seed germination of switchgrass. Optimum plant hormones for switchgrass seed germination was 200 μmol·L^-1 GA₄₊₇, which improved germination percentage up to 71%, 30% higher than the control.

Key words: Switchgrass, Seed dormancy, Plant exogenous growth substances, Germination

摘要：

为了提高柳枝稷（Panicum virgatum L.）种子萌发率，探究不同植物生长物质处理对柳枝稷种子萌发特性的影响，本研究以柳枝稷（Panicum virgatum ‘Forestburg’）种子为材料，采用不同浓度（0，10，50，200，400，1 000 μmol·L^-1）的赤霉素（GA₃，GA₄₊₇）、脱落酸（ABA）、6-苄氨基腺嘌呤（6-BA）、吲哚乙酸（IAA）、氟啶酮（FL）和多效唑（PA）等7种外源植物生长物质处理种子，分析柳枝稷种子萌发特性对不同浓度外源植物生长调节剂的响应。结果表明：10~200 μmol·L^-1 IAA和GA₄₊₇，10~50 μmol·L^-1 GA3，50 μmol·L^-1 6-BA及10 μmol·L^-1 FL均可对柳枝稷种子萌发产生显著促进作用（P<0.05），但是当其浓度过高时则会抑制柳枝稷种子萌发；ABA会抑制柳枝稷种子的萌发，PA对柳枝稷的萌发无显著作用；GA₄₊₇对柳枝稷种子萌发影响效果最好，其中经200 μmol·L^-1 GA₄₊₇处理后种子萌发率最高，可达71%，较对照提高30%。

关键词: 柳枝稷, 种子休眠, 植物生长物质, 萌发