Studies On The Biological Nematicidal Activity And Constituents Separation In Abutilon Theophrasti Against Meloidogyne Incognita

Root-knot nematodes, Meloidogyne spp., are highly damaging to many vegetable crops and cause significant yield loss, especially to greenhouse vegetable and to those planted in tropical and subtropical regions. Root-knot nematodes have also been shown to predispose plants to infection by fungal or bacterial pathogens, which contribute to additional yield reductions. Besides of use of resistance cultivars, agricultural practice and physical measurement, use of chemical nematicides and fumigants is an important means of controlling root-knot nematodes. Problems can occur with conventional nematicides and fumigants usage, however, as many cannot be applied to vegetables because of the high risk of potential toxicity to non-target organisms, residues and environmental hazards. New nematicides are needed to replace conventional chemicals, likely to be phased out in the near future. For seeking new friendly nematicide for controlling Meloidogyne incognita Chitwood become an urgent task。The nematicidal constituents in water extract of Me-OH extractions from Abutilon theophrasti Medic were studied with bioassay in present paper. The results would provide some theoretical basis for the research and development of friendly nematicides. The results could be summarized as follows:1. The Abutilon theophrasti Medic extractions from different solvent have significant difference in meloidogyne incognita nematicidal bioactivity. Using different solvent to extract Abutilon theophrasti, and got4components which extracted by petroleum ether, ethyl acetate, mehanol and water respectively, then did the nematicidal activity experiment. The result showed, when the dry powder treated concentration wwre50mg/mL and25mg/mL,that distilled water extraction had the best nematicidal activity, meloidogyne incognita treated by it reach to100%adjusted mortality at48h, and follow was the MeOH extraction, which had90%adjusted mortality at48h. But ethyl acetate and petroleum ether extraction treatment had low adjusted mortality. The nematicidal activity comparation was: water extraction> MeOH extraction> ethyl acetate extraction> petroleum ether extraction.2. The alkaline water layer of Abutilon theophrastir crude extraction have excellent nematicidal activity. Alkaloid in Abutilon theophrasti extraction was crude extracted, obtained3components, they were alkaline water layer, chloroform first layer and chloroform second layer. The nematicidal activity comparation was:alkaline water layer> chloroform layer Ⅰ> chloroform layer Ⅱ. The alkaline water layer had high nematicidal activity, when the dry powder concentration was200mg/ml, the adjusted mortality at24h and48h reach to100%. 3. Abutilon theophrasti extractions had significant difference on nematicidal activity. Extraced the Abutilon theophrasti alkaline water layer form small polar to big polar, obtained12components, found that A5component which was chloroform:MeOH (4:1) and A8component which was chloroform:MeOH (1:2) had good nematicidal activity. When the dry powder of A5component concentration were500mg/ml,250mg/ml and125mg/ml, the adjusted mortality at48h reach to100%. When the dry powder of A8component concentration were500mg/ml and250mg/ml, the adjusted mortality at48h reach to100%, even the treatment which concentration was125mg/ml, the adjusted mortality reach to93.2%.4. It was the first system research on the meloidogyne incognita nematicidal activity substance in Abutilon theophrasti water extraction of MeOH-Ext using the method of biological activity tracking. Obtained2more purer components by adopting silica column chromatography method and GC-MS technology. Then analyze the2more purer components using methyl alcohol of GC-MS. The results showed that:it was quite possible that the active substance was oleic acid, linoleic acid etc.5. Greenhouse experiment was conducted on Abutilon theophrasti extractions. The results showed that Abutilon theophrasti extractions had good control efficiency on tomato root nematode, especially when the concentration were1%,、0.5%and0.25%the effect were significantly. The specific embody were small number of root-knot, big growth rate of tomato fresh weight, and significant growth rate of root.