Study On Extraction Of Amaranthus Tricolor Active Substance And Inhibition Of Plant Pathogenic Fungi

This laboratory group has researched the Amaranthus tricolor active substance that extract with ethyl acetate. In this investigation,we used sterile water to extract the active substance from Amaranthus tricolor to study the inhibition of plant pathogenic fungi. With a view to develop a new fungal biocontrol agents of plant origin, provide a scientific basis for the expansion of the new features improve the utilization of amaranth, research content and results are as follows:1, The Amaranthus tricolor active substance that extract from water has a good inhibitory effect to the Rhizoctonia solani、Phytophthora capsici、Phytophthora sojae The inhibition rates were 66.27%、51.24%、21.14%.But to the other tested pathogenic fungi such as Sclerotinia sclerotiorum and Pyricularia oryzae just have a low inhibitory effect.2, When the proportion of Amaranthus tricolor powder and sterile water was 1:20, temperature at room temperature,the extraction time under 24h conditions, the extraction rateie was 8%.Finally the supernatant by rotary evaporation under reduced pressure to give 1.6g cream,then we got the liquid concentration was 40mg/mL after we used sterile water constant volume the cream.3, Different drying method also had different effects,The sun dried and the dried by blower had better effect than directly dried,the inbibition was sun dried(61.69%),dried by blower(53.50%),directly dried(47.14%).Different growth period of Amaranthus tricolor had different effects;The Growing phase was the best,the inhibition was 63.49%;The second was Young phase,the inhibition was 48.62%;The last was Senescence phase,the inhibition was 35.05%. In the different parts of amaranth growth the inhibitory activity was inconsistent, leaves, roots, stems inhibition rates were respectively 60.67%,51.41%, 43.42%.4, The optimum extraction conditions of Amaranthus tricolor extracts determined by the single factor experiment method were as follows:The results of the studied on different solid-liquid、temperature、oscillation times、oscillation time proved that when they were 1:5、30℃ and 24h had the maximal inhibitiono rate.The results of the orthogonal design test showed that the optimum extracting condition was the 1:5、30℃、24h。5, The active substance had less effective after high temperature,the inhibition rate was reduced from the original 67.21% to 31.12%.It follows that the Amaranthus tricolor active substance was not thermostability. Further research found that when we added proteinase K the inhibition rate was reduced from the original 67.21% to 35.42%,It can be concluded that there was protein in amaranth active substance,and It played an important role to the inhibitory effect.The above results show that the Amaranthus tricolor extracts have a strong inhibition effect against phytopathogenic fungi. This plant has great potential value for use as a biocontrol agent meantime,it provides a new ider for the development of new,safe, environmentally friendly pesticide..