甘薯对马铃薯腐烂茎线虫趋化性的影响

摘要

The potato rot nematode,Ditylenchus destructor Thome could cause severe damage to sweet potato.Phytochemicals of host plant play important roles in nematode behavior.In order to obtain extracts with high attraction activity to D.destructor,the chemotaxis of D.destructor to different sweet potato cultivars were investigated on water agar plates.The results showed that the storage roots of susceptible cultivars Lizixiang were significantly more attractive than the other cultivars.Sweetpotato was consistently attractive to the nematodes in all these assays.Nematodes around the sweet potato increased with the resident time,and the chemotaxis index reached 20％ after 96 h.Compared with the stem sap,leaves and storage roots,stems showed the strongest attraction ability to nematodes.No significant differences in relative attractiveness were detected between the fresh sweet potato stems and the stems that heated at 80 ℃ for 8 h,indicating that the attractant from sweetpotato was stable to heat.Furthermore,the compounds of sweet potato were extracted and determined in relation to the host-finding behavior of the nematode.The chemotaxis index of the fraction extracted with alcohol was 6.7％,which were significantly more attractive than the other fractions.%由马铃薯腐烂茎线虫侵染造成的甘薯茎线虫病是一种严重影响甘薯产量和品质的病害.线虫向寄主根部移动及取食危害可能是受寄主释放的化感信息物质控制.为最终明确甘薯中对线虫具有高效引诱能力的物质,本研究利用水琼脂平板法测试了甘薯不同品种与不同组织对线虫的引诱作用.结果表明不同品种甘薯薯块和薯茎对马铃薯腐烂茎线虫引诱能力具有一定差异,感线虫品种栗子香的薯块对线虫的引诱率要高于其他测试品种.随着薯块/薯茎在水琼脂平板上放置时间延长,其吸引线虫的效果增加,96 h后引诱率达到20％.同一品种甘薯茎的引诱能力显著高于薯块、薯叶.甘薯中所含对线虫具引诱作用的活性物质对热稳定,80℃加热8h后薯茎对线虫引诱率与新鲜茎相比无显著差异,为4.5％.甘薯茎经过不同有机溶剂分别萃取后,乙醇萃取物对线虫的引诱率为6.7％,显著高于其他萃取物.本文初步明确了甘薯中所含线虫趋化物的性质,为其开发应用奠定了基础.