Studies On Physiological Mechanisms Of The Improved Resistance To CMV By Epi-Brassinosteroid In Pumpkin (Cucurbita Pepo L.)

Epi-Brassinosteroid (EBR) is one of the most applied brassinosteroids (BRs) with a long studying history in plant growth regulation. Recently, the roles of BRs under abiotic and biotic stress conditions are receiving increasely attention. However, the mechanism by which BRs increase disease resistance is not clear. In order to illustrate the roles of EBR in alleviating diseases, experiments were carried out to study the effects of exogenouslu applied EBR on CMV infection in pumpkin (Cucurbita pepo L.). The main results were as follows:1 EBR treatment decreased the percentage of CMV-infected plants and the disease index in pumpkin plants. Meanwhile, virus content in pumpkin leaves was also reduced after EBR treatment, indicating that EBR increased the resistance to CMV in pumpkin plants.2 There was a sharp increase in H2O2 accumualation in pumpin leaves after foliar spraying with EBR. MDA content, however, was not influenced by EBR treatment. A high level of H2O2 was due to the decreasing of H2O2-degrading enzymes activity at the...