辣椒根系分泌物对西瓜根结线虫的影响及抑线虫物质初探

Effect of Pepper Root Exudates on Watermelon Root-knot Nematode and Preliminary Study on Nematode-suppressing Substance

利用根系分泌物自动收集装置分别收集了对根结线虫不同抗性的辣椒品种‘青农簇生椒’(中抗)和‘农家小尖椒’(感病)的根系分泌物,分别探究了两种根系分泌物对南方根结线虫孵化率及西瓜根结线虫幼虫和繁殖体数量的影响,同时将两个辣椒品种的根系分泌物组成成分进行比对和分析,结果表明:抗病品种‘青农簇生椒’根系分泌物对线虫孵化的抑制作用高于‘农家小尖椒’根系分泌物和对照(蒸馏水)处理。‘青农簇生椒’辣椒分泌物处理的西瓜根内根结线虫二龄幼虫和雌成虫及根围二龄幼虫和卵粒数量均显著低于对照。经GC-MS分析,两种辣椒根系分泌物成分分别为17种和18种,在抗线虫辣椒‘青农簇生椒’根系分泌物中出现了不抗病辣椒品种‘农家小尖椒’根系分泌物中没有的酯类——邻苯二甲酸二丁酯(DBP)。对不同浓度的DBP处理的线虫孵化和二龄幼虫成活情况研究,发现随着DBP浓度的升高,南方根结线虫的生长和繁殖均受到了抑制。该试验初步确认了辣椒根系分泌的化感物质DBP在抑制南方根结线虫的生长和繁殖方面起到了积极作用。

In the experiment,root exudate automatic collectors were used to collect root exudates of two pepper cultivars with different resistance to southern root-knot nematode(cv‘Qingnong clustery pepper’(middle-resistant)and‘Nongjia small pepper’(susceptible)).Effects of these two pepper cultivars root exudates on the hatchability of southern root-knot nematode and quantity of root-knot nematode second-stage juveniles and eggs were studied,Meanwhile,the constituents of root exudates from two cultivars were compared and analyzed.The results showed that the inhibitory effect of root exudates of the disease-resistant cultivar‘Qingnong clustery pepper’on nematode incubation was stronger than that of the root exudates of‘Nongjia small pepper’and control(distilled water).The numbers of root-knot nematode second-stage juveniles(J2)and female adults in roots,and J2 and eggs in rhizosphere of watermelon treated with‘Qingnong clustery pepper’root exudates were significantly lower than control group.According to GC-MS analysis,the numbers of components of root exudates of the two pepper cultivars were 17 and 18,respectively.Dibutyl phthalate(DBP),an ester that was not found in root exudates of the susceptible‘Nongjia small pepper’,but appeared in the nematode-resistant‘Qingnong clustery pepper’.In the experiment,nematode incubation and survival of second-stage juveniles under treatment with different concentrations of DBP were analyzed.The results showed that with the increase of DBP concentration,growth and propagation of southern root-knot nematode were inhibited as well.In conclusion,in our experiment it was preliminarily confirmed that the allelochemical DBP excreted by pepper roots played a positive role in inhibiting growth and propagation of southern root-knot nematode.