Effects Of BTH On Control Of Anthracnose Of Postharvested Mango Fruit And The Mechanisms Of Systemic Acquired Resistance(SAR)

Mango is one of the important tropical fruits. Every year, diseases costs large losses. One of the major diseases is Anthracnose. In recent years, using their own fruit and vegetable production inducer induced systemic acquired resistance has become a new means of disease control in fruits and vegetables.The effects of BTH on the control of anthracnose of postHar-vested"Nang klangwan" and" Tainong" Mango and its storage quality and the mechanisms of systemic acquired resistance induced by BTH were studied by inoculation and storage experiment in this paper. The results are as follows:1. The incidence of anthracnose of postharvested "Nang klangwan" and" Tainong" Mango were found to be evidently reduced by treating with BTH. Disease incidence rate of the fruit and changes in lesion area were determined. The result showed that BTH treatments with concentrations within the range of 50 to 300 mg/L had inhibitive effect on anthracnose. The optimum concentration was 200 mg/L for"Nang Klangwan" and 50 mg/L for "Tainong". The disease incidence of anthracnose and the expansion rate of lesion area in controlled "Tainong" are lower than controlled "Nang klangwan" Mango.2. Treatment of BTH increased the content of Titralable acid(TA),and delayed the decreased of the hardenss, Vitamin C(Vc) and rise of total soluble solids(TSS), reducing sugar and the changing degree of color and intenerating of fruit, indicating that BTH treatment could delay the progress of fruit ripening, guarantee the storage quality of "Nang klangwan" and" Tainong" Mango.3.Treatment of BTH can decreased the development of pathogen in the fruit of Mango, it mainly induced Mango fruit to produce SAR that containing increased the activity of peroxidase(POD),poly-phenoloxidase(PPO), phenylalanine ammonia-lyase(PAL), Superoxide dismutase(SOD), increased the content of secondary metabolites such as phenolic compound, flavanoid, hydroxyproline-rich-glycoprotein(HRGP),lignin, stimulated the production of AOS and increased the activity ofβ-1,3-glucanase (GLU), delayed the decreasing of the chitinase (CHT) activity in the fruit of mango.4.After the controlled "Tainong" mango was inoculated with Colletotichum gloeo-sporioides,that the content of secondary metabolites, the production rate of superoxide anion(O2.-),the activity of defensed enzyme and dumped radical enzyme in mango fruit were higher than the controlled "Nang klangwan" mango,it might be due to the resistance of against diseases of "Tainong" mango are stronger than the "Nang klangwan" mango,leads to the disease incidence rate of "Tainong" mango are lower than "Nang klangwan"mango. 5.After BTH treatment, the activity of defensed enzyme and dumped radical enzyme and the rising rate of the content of secondary metabolites in "Tainong" mango are obviously higher than "Nang klangwan" mango, it might be due to the better effect of resistance against diseases of the "Tainong" mango with the lower BTH treatments concentrateons.