Analysis On Sunburn Injury Mechanism And Frostbite Reason Of Pear Trunk Cambium And Its Prevention Measures

Korla Fragrant Pear(Pyrus bretschneideri Rehd.), one of the famous characteristic fruits in XinJiang Province, has high economic effects and become local important source. In the past few years, the influence of various breeding conditions related to climate change and atmospheric temperature, solar radiation, wind speed, etc., have brought serious harm to the Korla Fragrant Pear in the winter, which result in lager area tree chilling and sunburn injury and huge economic losses. Therefore, further researching on Pear cold resistance mechanism and understanding climate characteristic of the region, and discussing prevention measures to reduce the cold injury can provide a scientific basis for the expansion of cultivated area. Precious study on the main features of Xinjiang pear fruit mainly focus on measuring related protective Enzyme of dynamic characteristics, genesis of Korla Fragrant Pear tree trunks and sunburn injury by monitoring the low temperature natural stem cambium conditions, the impact of different heights stem trunk cambium temperature changes and solar radiation on the trunk cambium tissue. Then, comparative analysis of protective measures for the safety of winter pear were conducted. This study can provide reference for reducing the injury of frost and sunburn trunk cambiums caused by the dual role, and taking various protective measures insulation and shading, etc., so as to provide a scientific basis for the pear chilling phenomenon and sunburn forecasts and disaster management. The results are as follows:(1)In the winter, the alternating between day and night, light and dark direct, and the strong light exposure for a long time the sunny side of the trunk cambium tissue injury, resulting in serious injury on the formation of the surface layer of the sun sunburn and pear tree on the sunny side organization. Which induced more frost injury on the sunny side than the trunk cambium night side.(2)The temperature difference of different height cambium of Korla Fragrant Pear lead to different injury. The injury is more serious near the ground and light in higher cambium. Because the temperature of near the ground changes greatly. Thus, citrus tree near the ground should be covered and protected to alleviate the injury.(3)In a variety of weather factors, solar radiation is the main factor that lead to the formation of surface temperature changes. The temperature can be formed as a measurement of the amount of layers and low temperature characteristics.(4)Trunk cambium and shoots, flower buds, POD, SOD, and CAT enzyme activity have significant difference during in the winter period. The pear flower buds and branches are relatively sensitive to the freezing point. The most sensitive point is the sunny side of the trunk cambium forming layer. However the least insensitive part of the tree is the night side cambium.(5)The anti-freezing measure effect of the order of several measures are as follow: control <twine <reflective film <velvet mats <straw. The comparisons indicated that the measures covered by straw-covered are better than velvet rope, reflective screen and felt-sided.The effectiveness of different shading measures are showed as the order: blackened<scraping bark <control <painted red < scraping white. Description of such measures can effectively reduce the temperature change of pear tree trunk cambium. White-shading have the best anti-freezing effect on the tree trunk cambium with the smallest daily range and can be used as effective measurement during the winter.