Preliminary Study On The Antibacterial Activity And Control Mechanism Of Total Flavonoids In "Turubam" Leaves

Verticillium is one of the most serious diseases during the growth of eggplant.Solanum Torvum swartz is the common rootstock for grafting eggplant.The crude extract of “Solanum Torvum Swartz” leaves is characterized by a relatively high bacteriostatic activity in verticillium wilt of eggplant,because the extract contains flavonoids.This experiment extracts flavonoids from the leaves of Solanum Torvum swartz using plant chemical method,measure the inhibition to the growth of verticillium wilt fungus hypha using growth rate method,investigate the prevention effect to verticillium wilt of eggplant by pot and field tests,and finally determine the physiological indicators related to the disease resistance of field plants and the biological activities of rhizosphere soil,and explore the physiological and ecological mechanism how flavonoids to manage verticillium wilt of eggplant.Results show that flavonoids in the leaves of Solanum Torvum swartz have strong inhibition to the growth of verticillium wilt fungus hypha,significantly both in potted and field plants,can regulate the physiological indicators related to the disease resistance of eggplant and stabilize the micorecological rhizosphere environment.This paper can be used as the theory basis for management of verticillium wilt of eggplant by flavonoids in the leaves of Solanum Torvum swartz,provides a reference for the development of botanical fungicide,and supplements for the disease resistance theory of grafting eggplant.The experimental results are as follows:1.The inhibiting effect of flavonoids contained in “Solanum Torvum Swartz”leaves on the growth of eggplant verticillium hypha gets strengthened as the extract concentration increases.The inhibition ratio of 40mg/m L extract reaches 82.0789%,which is not significantly different from the inhibition ratio of the crude extract of“Solanum Torvum Swartz” leaves.Thus,it is believed that flavonoids compounds make up the main antibacterial component in the crude extract of “Solanum Torvum Swartz”leaves.2.As shown by the pot experiment,flavonoids in “Solanum Torvum Swartz”leaves have the best preventive effect on verticillium wilt of eggplant when itsconcentration reaches 8g/L and have the best treatment effect when the concentration reaches 10g/L.8g/L flavonoids contained in “Solanum Torvum Swartz” leaves have a relatively good effect on preventing verticillium wilt of eggplant in the field.Before the plant is infected,flavonoids contained in “Solanum Torvum Swartz” leaves have a significant function in increasing the stem diameter of the plant.After the plant is infected,both stem diameter and root length of the treated plant are higher than that of CK,but the plant height is significantly lower than that of CK.3.The treatment with flavonoids in “Solanum Torvum Swartz” leaves increases the chlorophyll content and root vitality of healthy and infected eggplant leaves.Under the circumstances of pathogen infection,the treatment with flavonoids in “Solanum Torvum Swartz” leaves decreases the increasing amplitude of electric conductivity of eggplant leaves and MDA content in the leaves,increases the content of proline and soluble sugar and improves the vitality of SOD,PPO and PAL,which thereby improves the disease resistance of the plant.4.Without pathogen infection,the treatment with flavonoids in “Solanum Torvum Swartz” leaves can increase the total amount of microorganisms in the rhizosphere soil of eggplant;after inoculation,the treatment with flavonoids in “Solanum Torvum Swartz” leaves can basically stabilize the structure of microorganisms in the rhizosphere soil of eggplant and A/F is obviously increased as compared with CK.Without pathogen infection,treated by flavonoids in “Solanum Torvum Swartz” leaves,the activity of dehydrogenase and polyphenol oxidase in rhizosphere soil of eggplant experience significant increase;after inoculation,the activity of dehydrogenase,catalase,peroxidase and polyphenol oxidase in the rhizosphere soil is obviously higher than that of CK.Thus,it is believed that flavonoids in “Solanum Torvum Swartz”leaves can stabilize rhizosphere microenvironment and reduce breeding of harmful bacteria,so as to lower the incidence of verticillium wilt of eggplant.