| Summary: | 碩士 === 國立臺灣大學 === 園藝暨景觀學系 === 104 === The long high temperature period makes flower bud abortion. In this study, pruning and 49% cynamide applcaition were used to let new lateral shoot growth in autumn (August to October) and the shoot length, flower formation, and dormancy were investigated in ‘Shinko’ (Pyrus pyrifolia) in Zhou-Lan. The highest percentage of bud break occurred in August, and it decreased in October as the dormancy development. Flower buds could be found during August to October, but the new shoot length was only 10 cm, and the growth ceased after a short time. These kind of shoots are not good enough to be the pear scion next year. Temperature is the key point to bud dormancy. Three Asian pear, bird pear (P. lindleyi), ‘Heng-Shan’ (P. pyrifolia), and ‘Shinko’ (P. pyrifolia) were put into 15/13℃, 25/20℃, 25/20℃, and 30/25℃, respectively, for 180 days. The vegetative growth of bird pear in 30/25℃, 25/20℃ ceased after 60-75 days. The shoots growth in 20/15℃ stopped after 120 days. However, the vegetative growth last for 180 days in 15/13℃. The vegetative growth of ‘Heng-Shan’ in 30/25℃ and 25/20℃ ceased after 45-60 days. The shoots growth in 20/15℃ stopped after 120 days. However, the vegetative growth also last for 180 days in 15/13℃. The vegetative growth of ‘Shinko’ stopped after 45-60 days in all temperature treatments. The floral formation could be investigated in all 3 varieties in 30/25℃. Three shoots were cut per month after July (after 120-day investigation) in every variety in all treatment. The percentage of bud break were above 33% during July to September in three varieties. It suggests the dormancy stage may be between paradormancy and endodormancy stage in September. However, comparing the bud break ratio of the shoots from Zhou-Lan dereased from 60% to 38% during July to September. Analyzing the carbohydrates and nitrogen contents in the shoots from Zhou-Lan during July to November. The total soluble solid decreased and the starch increased to the highest level after September. It suggests the dormancy stage would be into endodormancy in September.
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