The Effect Of LED Light On The Infection Of Botrytis Cinerea And The Defense System Of Tomato Leaves

In order to investigate the effect of LED light on the growth and infection of Botrytis cinerea, different light qualities LED were used to irradiate Botrytis cinerea colony and tomato leaves inoculated with Botrytis cinerea under different photoperiods. The optimum light quality and photoperiod condition of inhibition Botrytis cinerea was determined. This study provides a basis for preventing the occurrence and development of Botrytis cinerea by LED light environment in greenhouse in the future. In order to study the effect of different LED light environment on defense system of tomato leaf and investigate the physiological mechanisms of LED resistance Botrytis cinerea we measured the antioxidant enzyme activity and reactive oxygen species (ROX) content. Main research results were as follows:1. Purple and blue light could inhibit the growth of Botrytis cinerea. Purple and red light could inhibit the development of Botrytis cinerea lesion on tomato leaf. And photoperiods which were lOh/d,12h/d of purple light had better antibacterial effects because of its higher inhibitory rate and its faster inhibition Photoperiods which were 8h/d, 10h/d,12h/d of purple light and the photoperiod which was 12h/d of red light had better inhibitory effects, and the final inhibitory rate all reached more than 20%. Therefore we could use Purple and red light with appropriate photoperiods to prevent greenhouse tomato from Botrytis cinerea.2. Through the light pretreatment of Botrytis cinerea we found that the infection ability of Botrytis cinerea was inhibited only under the irradiation with purple light. Pretreatment of tomato leaf with red light could significantly inhibit the development of Botrytis cinerea, but the final inhibitory rate was lower than the red light photoperiod treatment and its inhibitory rate decreased with time.3. Red light could inhibit the oxidative burst of tomato leaves due to the infection of Botrytis cinerea. Red light could regulate the rapid increase and decrease of H2O2 content, which could promote the rapid occurrence of defense response and reduce the damage of tomato leaf due to high concentration reactive oxygen species. Red light could improve activities of SOD, POD, CAT in tomato leaves infected by Botrytis cinerea in different degree. And the red light photoperiods of 10h/d and 12h/d had the most significant improve effect. We also found that red light pretreatment can improve activities of antioxidant enzymes in tomato leaf and regulate the metabolism of reactive oxygen species. Therefore red light could improve the resistance of tomato to Botrytis cinerea through regulating the defense response and antioxidant abilities of tomato leaf.