| Early-fruiting Walnut is the type of walnut which accommodated with the rapid development of the current economic situation. Annual branches of early-fruiting walnut are the main pruning objects in shaping of young trees and adjustment of adult trees' fruit load, and if the pruning period was improper, bleeding will be easily occurred and a large amount of nutrient will be lost, and thus affecting the yield and quality of walnut. At present, the researches on variation of bleeding and influence factors on annual branch of early-fruit walnut in dormant period were relatively less. In order to determine the proper pruning period and guide production and reveal influence factors of bleeding rules of early-fruit walnut' annual branch in dormant period, the annual branches of Lvling walnut were used as materials to study the relationship of amylase activities, starch contents, soluble sugar contents, relative conductivity, the structure of annual branch and bleeding sap from November 2005 to March 2006 and from November 2006 to March 2007. The results were as follows.1. Occurring time of bleeding and appearing sequence of la~6a years tree were different in 2005 and 2006, but bleeding quantity various tendency in dormant period was similar, which was bimodal curve, and the first peak value was higher than that of the second one. Annual branch bleeding of 1 years old tree occurred earlier than that of others in 2005, and annual branch bleeding of 1a～6a old tree occurred at the same time in 2006. In addition, the appearance time of bleeding peak was different in 2005 and 2006: December the 9th in 2005, and January the second in 2006. The bleeding quantity of annual branches of 3 years old tree was more than that of other ages significantly from December the 9th in 2005 to January the 18th in 2006, the bleeding quantity of annual branches of 4 years old tree was the most from February the 7th in 2006 to April the 8th in 2006; There was no bleeding sap appeared of all annual branches at the early of April. In 2006, annual branches of 1a～6a old trees occurred to bleed on November the 24th which was the second day after light snow of solar term. Then with the decline of temperature, bleeding sap quantity ascended sharply and up to the first bleeding peak on January the second which was the 11th after midwinter of solar term. After that bleeding quantity of annual branches declined sharply and down to the first trough on January the 22nd which was the second day after severe cold of solar term, and from then on bleeding quantity kept smooth or ascending slight till February 11th which was the 7th day after spring begins. After that bleeding quantity was declining gradually and stopped on March 24th which was the third after vernal equinox.Bleeding rule in a day in different period of 1 to 3 year old tree was that the bleeding time and bleeding quantity peak were delayed by the air temperature falling down, at the same time, the bleeding stopping time was advanced, the persisted time was shorten and the bleeding quantity was decreased.2. The relation between bleeding quantity of annual branches and temperature in dormant period was studied. The results showed that the bleeding quantity variety of annual branches of different old trees was bimodal curve. Bleeding quantity of annual branches of 3 a and 4a trees was up to the first peak at 0℃, and others were up to the first peak at 2.0℃. With the decline of temperature, bleeding quantity declined gradually and stopped at-5℃. And then with the ascent of temperature, it was up to the second peak at 6℃, and then declined. The bleeding of annual branches of la~6a was disappeared at 9℃.3. The relation between amylase activities,starch content and solubility sugar content and bleeding quantity were studied in dormant period. The results showed that there existed significant or very significant positive correlation between amylase activities and bleeding sap quantity of annual branches, the correlation coefficients were 0.7296～0.9017. There existed negative correlation between starch contents and bleeding sap quantity of annual branches, the correlation coefficients were -0.6361～-0.8005; there existed very significant positive correlation between soluble sugar contents and bleeding sap quantity, the correlation coefficients were 0.8814～0.9685. Soluble sugar contents and amylase activities were the factors which affected walnut bleeding in dormant period.4. The results of relatively conductance of annual branches by means of different low temperature treatment were that electrolytical exudation of annual branches through different low temperature treatment were S-type curve obviously. Relatively conductance of annual branches were exceed 30% and relatively conductance of annual branch of annual tree was up to 42.6% at 5℃, this illuminated that cellularity of annual branches had been damnified at 5℃to some extent; relatively conductance of annual branches was declined slightly at -5℃; it was increased greatly at -10℃and it was up to 65% at -20℃, even relatively conductance of annual branches of 4 years old tree was up to 78 % at -20℃.5 The relation between the structure of annual branches and bleeding sap quantity was studied. The results showed that during the early and the middle of dormancy, there existed very significant positive correlation between bleeding sap quantity and the area of wood of annual branches, the correlation coefficients were 0.8390 and 0.9140 respectively; there existed significant positive correlation between bleeding sap quantity and the area of vessels, the area of wood/transverse area, the correlation coefficients were 0.7470, 0.8160 and 0.7660, 0.7090 respectively; there existed significant negative correlation between bleeding sap quantity and the area of bark/ transverse area, the correlation coefficients were -0.7660 and -0.7100 respectively; during the last of dormancy, bleeding quantity of annual branches were less, and no significant correlation between the area of wood, the area of wood/transverse area, the area of bark/transverse area and the area of vessels.
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