Study On Nourishment Changes And Respiratory Metabolism Of Dormancy Pear Buds

The physiological and biochemical metabolisms did not stop after the deciduous fruit trees into dormancy. This experiment was carried out during 2007-2008 in Agricultural University of Hebei. The relations of respiratory metabolism and dormancy were studied in Ya Pear. The main results were as follows:1.The contents of soluble sugar first raised, later dropped and then raised. The soluble sugar of buds reached the top contents in the middle of January. The contents of starch first dropped and then raised. The trendency showed inverse relationship with that of the solube sugar. The minimum content of buds appeared in the middle of January. GA3 and SA raised carbohydrate content, and higher of concentration of growth regulators was, better effects of it had.2.The changes tendency of protein contents of bud showed first dropped then raised and then dropped again, ascending before germination. The maximum contents were in the middle of January. The changes tendency of amino acid contents of bud showed the tendency ascend first, decreased later and ascend last, the maximum contents were in the last of January. GA3 and SA decreased the content of protein. Higher concentrations of regulators were, more evident effects were. GA3 and SA increased the contents of amino acid.3.During dormancy period, PGI activity dropped and SDH activity changed little during dormancy period.G-6-PDH and 6-PGDH activities enhanced. Effects of GA3 and SA on them were reverse. The higher of regulators concentration the better effect they had.That changes of enzymes were consistent with respiratory pathway of regulators indicated that GA3 and SA were helpful to dormancy release by enhancing activities of G-6-PDH and 6-PGDH.4.Respiratory intensity was high during early period while the temperature was high in climate,then decreased and was very stable on a lower metabolic level for a long time,only increased slightly after the end of dormancy.As temperature increases,the respiratory intensity had a sharp raise. Different kinds of respiratory pathway changed obviously:the rate of TCA was stable and took a dominant position.The rate of EMP took a dropping trend but that of PPP had a obviously rising trend. Spraying. GA3 and SA raised respiratory intensity and raised rates of TCA and PPP but drop that of EMP. Higher concentrations of regulators were,more evident effects were. The EMP rate and the HMP rate in the buds treated in low temperature were increased and decreased respectively. But TCA rate was on the same level as contrasted buds.The reversed results of that treated in high temperature had been obtained.