劲直黄芪水浸提液化感作用研究

采用培养皿滤纸法,首次研究了分布于西藏自治区的劲直黄芪地上部分水浸液对4种受体植物燕麦、反枝苋、白三叶和荠菜种子萌发、幼苗根长、苗高和鲜重的化感效应以及对燕麦和白三叶丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)活性的影响,旨在提示劲直黄芪的化感潜力,为劲直黄芪资源的进一步开发利用提供理论依据。结果表明,劲直黄芪水浸提液对燕麦种子萌发和幼苗生长均表现为抑制作用,且随着劲直黄芪水浸提液浓度的升高其抑制程度不断增强;对反枝苋、白三叶和荠菜种子萌发均表现为抑制作用,幼苗生长基本呈“低促高抑”的化感作用,且浓度达到100.0 mg/mL时,反枝苋种子不能萌发,被完全抑制了。不同浓度的劲直黄芪水浸提液影响燕麦和白三叶幼苗体内SOD、POD活性和MDA含量,当浓度为50.0 mg/mL时,SOD、POD活性和MDA含量明显增加;浓度升高到100.0 mg/mL时,MDA含量继续增加,而SOD和POD活性呈下降趋势。

Research on allelopathy of aqueous extract from Astragalus strictus

Aboveground parts of Astragalus strictus distributed in the Tibet autonomous region, was used to prepare aqueous extracts to test the allelopathic effects on Avena sativa, Amaranthus retroflexus, Trifolium repens and Capsella bursa-pastoris using Petridishs with filter papers. Allelopathic effects of aqueous extract were tested on seed germination, root length, seedling height and fresh weight of four species of Astragalus. The malondialdehyde (MDA) content, and the activities of superoxide dismutase (SOD), and peroxidase (POD) of A. sativa and T. repens were investigated to reveal the allelopathic potential of A. strictus, and thereby to provide a theoretical basis for further development and use of A. strictus resources. The aqueous extract inhibited seed germination and seedling growth of A. sativa, and the inhibition was enhanced with an increase in extract concentration. Seed germination of A. retroflexus, T. repens and C. bursa-pastoris were also inhibited by the aqueous extract, and the effects on seedling growth presented an obvious ‘concentration effect’, promoting growth at the lower concentrations and inhibiting growth at the higher ones. A. retroflexus seed germination was inhibited completely when the aqueous extract concentration was 100 mg/mL. The activities of SOD, POD and MDA contents of A. sativa and T. repens were affected by different concentrations of aqueous extract. SOD, POD activities and MDA content markedly increased at 50 mg/mL aqueous extract, whereas at 100 mg/mL, the extract increased MDA content and reduced the enzyme activity in the seedlings of A. sativa and T. repens. Therefore, A. strictus shows a great allelopathic potential.