Study On The Inhibitory Effect Of 10 Kinds Of Extracts Of Chinese Medicine On Pestalotiopsis Theae

Tea gray blight was a kind of important disease of tea leaves,cause by the Pestalotiopsis,after infection with tea gray blight,tea tree leaves showed round spot symptoms,the disease was mainly harm leaflets of leaf,leaf margin,also had certain influence to the young leaves and tender tip,can cause large amount of fallen leaves,and had seriously harmed the economic benefits of tea farmers.Tea gray blight happened in our country and all over the world,in tea garden with machine mining or overprune occurred more and more serious.In this study,10 common Chinese medicinal herbs were used as the research objects,and the anti-fungi activity of their extracts against eight common agricultural pathogens such as tea grey blight was evaluated,and the anti-fungi active ingredients with the best anti-fungi activity were further analyzed.The main findings are the following three aspects:1.The growth rate method was used to test the inhibitory effect of 10 kinds of traditional Chinese medicine（Aster tataricus、Macleaya cordata、Litsea pungens、Rubia cordifolia、Spatholobus suberectus、Rostellularia procumbens、Elsholtzia ciliata、Euodia rutaecarpa、Atractylodes macrocephala、Citrus aurantiummethanol）extract on 8 kinds of fungi（Colletotrichum siamense、Colletotrichum fructicola、Pestalotiopsis theae、Colletotrichum gloeosporioides、Alternaria alternata、Fusarium oxysporm、F.commune、Botryosphaeria dothidea）,and the results showed that among the ten Chinese herbal medicines,the inhibition rate was more than 70%,at 2 mg/m L,M.cordata extract had a good inhibitory effect on P.theae,with an inhibition rate of 79.3%,The inhibitory rate of the extract of L.pungens.against F.oxysporum and P.theae was 72.9% and 89.9%.The inhibitory rate of E.ciliata extract against P.theae、C.gloeosporioides and C.siamense was 89.07%、81.37% and 76.00%,others is under 70%.2.Four groups of experimental groups with good bacteriostatic effect were selected for virulence testing,among which the EC₅₀ of E.ciliata extract on P.theae was 2848.15 μg/m L,the EC₅₀ of Macleaya cordata extract on P.theae was 391.20 μg/m L,the EC₅₀ of L.pungens extract against F.oxysporum was 1415.46 μg/m L,and the EC₅₀ of C.aurantium extract on F.commune was 11621.34 μg/m L.Among the four groups of experiments,the best bacteriostatic effect was M.cordata extract on P.theae experimental group.3.In this paper,the M.cordata was analyzed by using LC-MS,A total of 482 compounds were identified.Among them,the proportion of various components was as follows: lipids and lipids accounted for 31.61%,styrene and polyketones accounted for11.17%,organic acids accounted for 11.17%,benzene ring type accounted for 13.35%,organic oxygen compounds accounted for 12.81%,organic acids accounted for 11.17%,alkaloids accounted for 0.82%.The anti-fungi activity of sanguinarine,a representative component of M.cordata,against pathogenic fungi of tea gray blight was tested by mycelium growth rate method and spore germination method.P.theae morphology was observed by optical microscope,and cell permeability and reducing sugar content were measured by electrical conductivity.The results showed that the EC₅₀ of sanguinarine on pathogenic bacteria of tea gray blight was 5.93 μg/m L.The influence of sanguinarine on pathogenic bacteria of tea gray blight increased their electrical conductivity and reducing sugar content compared with the control group.The reducing sugar content showed a trend of slow decrease before 48 hours and sudden increase after 48 hours.These results indicate that sanguinarine may affect the normal growth of pathogenic bacteria by destroying the membrane of mycelia,so as to achieve the anti-fungi effect.