Study On Respiration Of Dormancy Nectarine Flower Buds

This experiment was carried out during 2002~2004 in Shan-dong Agricultural University. The dynamic changes of respiratory metabolism in dormant bud of two nectarine cultivars, Wuyuehuo and Shuguang, which have different Chilling requirements, were studied in the experiment. The soluble sugar, starch, soluble protein and amino acid in flower bud and scale, temperature, regulator, and shading were tested to discuss their effects on the respiratory metabolism. The main results were as follows: 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. Cultivars that need high chilling requirement had a high respiratory intensity and they were not sensitive to chilling, on the contrary, they were sensitive. Although respiratory intensity in the two cultivars maintained a low and stable level during the whole dormant period, respiratory pathway was different obviously: the TCA rate in nectarine was stable and was at dominant position; the EMP rate tend to decrease; and the HMP rate tend to increase.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. There was a little effect on the respiration of dormant buds in the shading treatment. The respiratory intensity increased only in the early dormant period when the flower buds were shaded, and the many shadow there are, the lot effect there is on the respiratory intensity. There was no effect on TCA rate in the treatment of peeling scale, but the HMP rate dropped and the EMP rate raised in this treatment. Ten days later, the nectarine flower buds withered,and it was probably because the scale has the function of safeguardDuring the whole dormant period, starch in bud accumulated slowly in earlier stage. The content of starch dropped sharply in the last of December. Soluble sugar content decreased in the early dormancy period and increased sharply in the last, whose change was consistent with the change of starch content. The jump-change stage of carbohydrate content was consistent with the process of respiratory pathway's change. The content of soluble protein decreased and the content of amino acid increased during the whole dormant period. Only when the dormancy finished, the content of soluble protein increased and the content of free amino acid decreased slowly. This is probably concerned with the process of respiratory pathway's change. Spraying growth regulators such as 6-BA or GA3 raised dormant bud respiratory intensity and the rate of TCA or HMP, but had little effect on the rate of EMP. Among these hormones, the effect of 6-BA was the most obvious, ABA spraying slightly dropped respiratory intensity and made the proportion of HMP drop but EMP raise, no effect on TCA rate。 Spraying growth regulators in later dormant period with GA3 and 6-BA made the starch content reduce quickly and increased the content of soluble sugar sharply, but ABA had no effect.