意大利苍耳的化感作用对油葵种子萌发的影响

实验在严格受控条件下研究了意大利苍耳不同器官的水浸提液对油葵种子萌发的影响,以评价在种子萌发阶段意大利苍耳对油葵的化感抑制潜力。结果表明,意大利苍耳各器官的水浸提液均对油葵种子萌发产生了强烈的、具有浓度和器官依赖性的化感抑制效应,随着浸提液浓度的提高,化感抑制活性显著增强;与根和茎相比,叶片和果实的化感抑制活性更强。意大利苍耳不同器官水浸提液不仅减缓了油葵种子的萌发速度、推迟了种子的萌发时间,而且显著地降低了油葵种子的萌发率;其中在100 g·L^-1浓度的根、茎、果实、叶片水浸提液中,油葵种子14 d的累积萌发率较对照组分别下降了27%、48%、53%和78%。因此,意大利苍耳凋落物和残茬的化感抑制作用所造成的油葵种子的萌发变缓、萌发延迟以及萌发失败,可能是导致油葵大量缺苗的重要原因之一。

Allelopathic Effects of Xanthium strumarium L.on the Germination of Oil Sunflower Seeds

In this study,the effects of aqueous extracts from different organs of Xanthium strumarium on germination of oil sunflower seeds were studied under strictly controlled conditions to evaluate the inhibiting potential of allelopathy of X.strumarium.The results showed that the aqueous extracts from different organs of X.strumarium had a strong,concerntration and organ-dependent allelopathic inhibitory effect on seed germination of oil sunflower,and the allelopathic inhibitory effect was significantly enhanced with the increase of the concentration of the extracts.Compared with roots and stems,leaves and fruits showed stronger allelopathic inhibitory activity to seed germination.And,the water extracts from different organs of X.strumarium not only slowed down the seed germination rate and delayed the seed germination time,but also significantly reduced the seed germination rate.In the aqueous extracts of roots,stems,fruits and leaves with the concentration of 100 g·L^-1,the cumulative germination rate of oil sunflower seeds at day 14 decreased by 27%,48%,53%and 78%respectively compared with the control group.Therefore,the slow germination,delayed germination time and failure of seed germination caused by allelopathic inhibitory effect of litters and stubble of X.strumarium may be one of the important reasons for a large number of seedlings missing.