The Effect Of Air Temperature On Cold Resistant Physiology Of Korla Fragrant Pear's Different Parts During Wintering Period

This article used AR5 automatic weather station, thermocouple tree temperature monitoring system and ESTDP 30 sap flow sensor, respectively detect the ambient air temperature, natural and infrared heated trunk cambium temperature, cambium temperature changes after covered with different color and different material during wintering period and monitor sap flow of infrared heated spot during active stage. Comprehensively evaluate the cold resistance of Korla fragrant pear's different parts by using subordinate function method, explain the effect and harm of air temperature and cambium temperature changes on the physiological indices and cold hardiness of Korla fragrant pear's different parts during over-wintering period. The main research content includes: the relation between the changes of orchard air temperature, trunk cambium temperature and the cold resistance indexes of Korla fragrant pear's different parts during wintering period; the effect and harm of alternately freezing range of trunk cambium on trunk tissues and sap flow; the comparison of the different covering measures. The main results are as follows:(1) The air temperature changes during cold hardening period affect the cold resistance of Korla fragrant pear in whole winter, the year which has smaller range of air temperature change during a certain period of time expressed stronger cold hardiness than the year which has bigger range of air temperature change during the same period of time. Subordinate function analysis results showed that Korla fragrant pear belongs to the medium cold resistant variety.(2) SOD is very sensitive to cell membrane injury, it can not express relatively high enzyme activity under the condition of relatively severe cell membrane damage.(3) Different parts has the highest relative conductivity in February, the part with the strong cold resistance expressed relatively higher Soluble Protein content and lower Relative Conductivity.(4) The cold resistance sequence of Korla fragrant pear's different parts during over-wintering period is flower bud> north-unexposed side cambium> branch> south-exposed side cambium.(5) Under the condition of infrared heating of trunk cambium, the range of alternately freezing and different physiological indexes are negatively correlated.(6) The harmful effect of alternately freezing on trunk tissues during over-wintering period caused advancing of the appearing time of diurnal maximum sap flow velocity during active stage.(7) The sequence of the freezing injury prevention effect of different covering measures is rice straw> wool mat> reflecting film> hemp rope> painting white.