The Research Of Control Effects Of Brassinosteroids Treatment On Tomato Root-knot Nematode Caused By Meloidogyne Incognita

Taken Lycopersicon esculentum Mill. as material in this paper, the exploration offoliar spaying2,4-epibrassionlide to improve the control effect and its mechanism oftomato to root-knot nematode were studied through pot and field trial. The researchaimed at providing new theoretical basis for the subsequent tomato nematode diseaseThe results were as follows：1. We studied the control effect of spraying different concentrations of the EBR(0.05μmol·L^-1、0.1μmol·L^-1、0.15μmol·L^-1、0.2μmol·L^-1and0.25μmol·L^-1on thetomato root-knot nematode. The results showed that the different concentrations allhad better control of tomato root-knot nematode, the control effect was up to39.37%,70%,56.15%,48.82%and44.90%; the the toxic effects of root-knot nematodewere up to32.01%,74.63%,65.9%,52.27%and42.55%. The best control effect wasthe0.1μmol·L^-1, which significantly reduced the number of root-knot of tomato,reduced the number of nematodes in the soil, and prevented the tomato root-knotnematode disease effectively.2. We studied the field efficiency of brassinosteroid on greenhouse tomato root-knot nematode. The results showed that exogenous spraying the0.1μmol·L^-1EBRpromoted the improvement of root activity and the quality of tomato, reduced theaccumulation of MDA, maintained the higher protected enzyme activities of APX、CAT、POD and DHAR, effectively reduced the generation and accumulation ofoxygen species （O₂Ë™-and H₂O₂） under the root-knot nematode stressï¼›induced the riseof the activity of metabolites enzyme, prompted the formation of secondarymetabolites, improved the content of root carbohydrate, increased the number ofmicroorganisms in the soil and improved the enzyme activities in the soil, therebychanged the structure of the soil population. Finally, brassinolide effectively reducedthe root-knot index of tomato and the number of second instar larvae at different depths in the soil(10-20cm,20-30cm,0^-10cm), the control effect was18.75%. Theexamination of histopathology and cytology of root showed that it caused formation ofthe nematode feeding sites-giant cells after root-knot nematode infected the plant rootsand these giant cells provided the necessary nutrients for nematode growth anddevelopment.3. Using three different tomatoes of BR levels（normal wild-type, synthetic mutantDimand deletion mutants Not） as materials, we studied the resistance to root-knotnematodes by exogenous spraying the0.1μmol·L^-1EBR. The results showed that theactivities of CAT and SOD in the different tomatoes had gradually increased with theincrease of the days of EBR spraying0.1μmol·L^-1EBR treatment, improved theactivities of CHT, reduced the content of H₂O₂and reduced the number of the root-knot and the number of second instar larvae in the soil, the nematode control effectwas respectively up to8.34%,16.66%and33.34%and the the toxic effects of root-knot nematode were up to65.52%,6.9%and41.38%.