薰衣草种子萌发及幼苗生长对干旱胁迫的响应

[目的]研究干旱胁迫对薰衣草种子萌发和幼苗生长的影响,探讨薰衣草的抗旱机理,为其种植栽培提供理论依据。[方法]以不同浓度的聚乙二醇(PEG-6000)模拟干旱胁迫对薰衣草种子及幼苗进行处理,测定种子萌发率、萌发指数、发芽势、活力指数以及幼苗的主根长、苗高、鲜重、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MDA)、可溶性糖(WSC)含量等指标,采用SPSS 20.0软件进行数据统计分析。[结果]随干旱胁迫强度的增加,薰衣草种子的萌发率、萌发指数、发芽势、活力指数均呈现下降趋势,轻度干旱(PEG-6000质量分数为2.5%~10.0%时)胁迫下,上述指标的变化差异不显著(P0.05);中度干旱胁迫下(PEG-6000质量分数为15.0%~20.0%),种子发芽率显著降低(P0.05);而当PEG-6000质量分数达到25.0%(重度干旱胁迫)时,种子几乎不能萌发;随干旱强度的增加,薰衣草幼苗的苗高、鲜重显著降低,主根长表现为先增加后降低。SOD、POD、CAT这3种抗氧化酶活性均呈现出先升高后降低的变化趋势;WSC含量随PEG-6000质量分数的增加而呈明显的上升趋势;MDA含量呈现出持续上升的趋势。[结论]干旱胁迫对薰衣草种子萌发和幼苗生长均有明显的抑制作用,但同时薰衣草种子及幼苗也能够通过其自身的生理生化变化来主动适应外界的干旱环境。

Response of Seed Germination and Seedling Growth of Lavandula angustifolia Mill.to Drought Stress

[Objective] The research aimed to study the effects of drought stress on seed germination and seedling growth of Lavandula angustifolia,discuss the drought resistance mechanism of Lavandula angustifolia and provide the theoretical basis for its cultivation.[Method] Using polyethylene glycol (PEG-6000) to simulate drought stress the change of seed germination rate,germination index,germination potential and vigor index of Lavandula angustifolia together with the main root length,seeding height,fresh weight,SOD,POD,CAT activity and MDA,WSC content of the seedlings were studied with different weight concentrations of PEG-6000.[Result]The seed germination,rate,germination index,germination potential and vigor index of Lavandula angustifolia seeds decreased generally with the increase of PEG-6000 mass fraction,but there were no significance(P ＞ 0.05)at mild drought stress (the PEG-6000 mass fraction was from 2.5％ to 10.0％):When PEG-6000 mass fraction was from 15.0％ to 20.0％,the germination rate significantly decreased(P ＜ 0.05):When the mass fraction was reached 25.0％,the seed could not germinate.The seedling height and fresh weight of the seedlings decreased gradually,while the main root length increased initially followed by decrease.SOD,POD and CAT activities increased initially and then decreased,while MDA content increased gradually throughout.[Conclusion] Drought stress has obvious inhibitory effect on seed germination and seedling growth of Lavandula angustifolia,but the seeds and seedlings of Lavandula angustifolia can also adapt to the external arid environment through their own physiological and biochemical changes.