以5个推广棉花(Gossypium hirsutum L.)品种(中棉所63、中棉所57、中棉所47、中棉所44和中棉所41)为研究对象,利用盆栽试验分别采集棉花苗期3个时期(二叶一心、四叶一心和六叶一心期)的根际土和植株样品,并用其甲醇浸提测试对向日葵列当(Orobanche cumana Wallr.)种子的发芽率.结果表明,根际土、植株样(根、茎和叶)甲醇浸提液诱导种子发芽率高低顺序为根际土>根>茎>叶,表明棉花的根际土和根的甲醇提取液对向日葵列当种子的萌发诱导作用较强.3个时期中,二叶一心期诱导向日葵列当的发芽在品种之间不存在显著性差异,表现为较稳定的诱导种子萌发作用.综合得出,棉花二叶一心期的根际土和根的甲醇提取液对向日葵列当种子萌发的诱导作用较强,二叶一心期为棉花作为"诱捕作物"生物防除寄生杂草提供科学依据.%The effect of extracts from five cotton (Gossypium hirsutum L.) varieties (Zhongmiansuo 63, Zhongmiansuo 57,Zhongmiansuo 47, Zhongmiansuo 44, and Zhongmiansuo 41) on sunflower broomrape (Orobanche cumana Wallr.) germination were tested. The cotton varieties were grown in separate pots. When the plants were at the two, four, and six-leaf stages, samples were collected from the rhizosphere soil as well as from the roots, stems, and leaves of the cotton plants. The samples were extracted with methanol and then the extracts were applied to sunflower broomrape seeds. The results indicated that seeds treated with rhizosphere extracts germinated first, followed by those treated with root extracts, stem extracts, and finally leaf extracts.Germination rates were highest when the seeds were treated with rhizosphere or plant extracts collected at the two-leaf stage. The varieties of cotton had no significant effect on sunflower broomrape germination when the seeds were treated with extracts collected at the two-leaf stage. In contrast, there were significant differences among the varieties when the seeds were treated with extracts collected at the four and six-leaf stages. In conclusion, cotton plants at the two-leaf stage had the strongest allelopathic effect on sunflower broomrape. These results provide a basis for using cotton as a “trap crop” for the bio-control of the parasitic weeds.
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