| The research had been carried out in college of horticulture science and engineering, Shan Dong Agricultural University from 2002 to 2004 with European sweet cherry trees "Jin JT e MM a", "PySuHOBaa", "Ba Ji e p H ft q K a ji o" and " C K o p o c n e ji K a" as experimental materials. Using High Performance Liquid Chromatography we studied the changes of endogenous hormone in sweet cherry flower buds during endodormancy. The effects of environmental factors(temperature, photo), de-scaled, defoliation, exogenous hormone and chemical medicines treatments on endogenous hormone and release of endodormancy of sweet cherry flower buds were also investigated. The main results were indicated as follow:1. With the development of endodormancy, ABA in flower buds deposited quickly and its maximum appeared in early November, then decreased continuously. Its minimum appeared in early January. Contrary to ABA, GAa and Zeatin content dropped sharply in primary stage of endodormancy and rose steadily during release of endodormancy, its minimum appeared in later November or early December. IAA content fluctuated greatly during endodormancy. Correspond to ABA, GAs and ZT, the values of ABA/GAs t ABA/ZT rose with the deepening of endodormancy and dropped with the release of endodormancy. Germination experiments indicated that the values of ABA/GAs, ABA/ZT were correspond to endodormancy degree.2. The effects of different temperature treatments on endogenous hormone content and release of endodormancy were different: low temperature ( 5 ) treatment hastened the decrease of ABA and the increase of GA3, ZT, as a result hastened the release of endodormancy. Germination rate of flower buds after low temperature (5 ) treatment were as high as 88.65%. While the effects of 20 treatment were contrary to 5 and it delayed the release of endodormancy. There were no obvious changes in endogenous content in flower buds and germination rate after 5/20 treatment.3. There were little effects of overshadow treatment on endogenoushormone content. It could decrease GA3, ZT content slightly, and the changes of ABA, IAA were small. The development of endodormancy couldn't be changed by overshadow treatments. The synthesis of GA3 was promoted and synthesis of ABA was inhibited after long photoperiod treatment, the changes of ZT were similar to that of GA3. Germination rate was as high as 85.56% after long photoperiod treatment. Contrary to that, germination rate was only 8.64% after short photoperiod treatment.4. ABA in dormant flower buds was distributed primarily in scales, ABA content in scales was far higher than that in de-scaled buds and whole buds. The synthesizes of GA3 and ZT in buds were promoted after shelling scales, however ABA content fall down sharply. Effects of shelling scales were different during different time of endodormancy, shelling the scales in ex-period and empress period could break endodormancy effectively, and germination rates were up to 66.80%, 89.65% respectively. In middle period it was only 53.57%. The sensitivity to exogenous hormone was strengthened, smearing over GA3 and 6-BA can break endodormancy effectively, the effect of GAS was better in early time and 6-BA was better in later time. Smearing over ABA promote the maintenance of endodormancy and the germination rate was very low.5. In autumn ABA were greatly synthesized in leaves of sweet cherry and transferred to flower buds, at the same time the decomposition of GA3, ZT was accelerated, which made ABA content in flower buds increase greatly. Taking off leaves could change the relationship between" source " and "warehouse", and decreased ABA content in flower buds remarkably. GA3, ZT and IAA contents backed up obviously during later period after taking off leaves. Moreover, taking off leaves could also increase H2O2 contains, activities of anti-oxidize enzymes SOD, POD and lower O2 content remarkably so as to dissolves disservices brought by activated oxygen. The descent of CAT activity resulted to the bac...
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