Indices Related to the Resistance of Yuluxiang Pear to Stresses

During the period of floral bud differentiation, the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and the content of MDA in the two normal bud-growing orchards all increased at first and decreased subsequently. High temperature and high humidity stress can lead to the accumulation of reactive oxygen in plants, aggravate membrane lipid peroxidation and accelerate vegetative growth[s]. Determination of antioxidant enzyme activities and malondialdehyde (MDA) content The activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were determined according to the methods previously described[6]. in brief, 0.6 g of the bud sample was ground in a mortar on ice by adding 2 ml of phosphate buffer (pH 7.8, 50 mmol/L) and a little quartz sand, transferred into a centrifuge tube, and centrifuged at 10 000 r/min for 15 min, to collect the supernatant, which was the enzyme extract. The POD activity in the normal buds in Wei County was higher than that in withered buds, and the high POD activity relieved the stress caused by reactive oxygen, so that the buds of Yuluxiang trees can develop normally. [...]branch blending, water control, girding and spraying growth retarder and so on can decrease the vegetative growth of pear trees under high temperature and high humidity conditions, improve the resistance of buds to stresses, which is beneficial to the development of floral buds, and as a result, the percentage of withered buds is reduced.