Studies On Floral Bud Differentiation And Biochemical Changes Of Day Neutral Strawberry

The objective of the study is to investigate the reproductive process of the flower bud differentiation of day-neutral strawberry and the changes of biochemical changes during flower bud differentiation. In this study,by using anatomical methods observed the processes of flower bud formation and inflorescence differentiation and measured the changes of carbohydrates, nitrogen compounds,endogenous hormone levels during flower bud differentiation. In order to provide a theoretical basis for the study of day-neutral strawberries the pollen number, malformed pollen and effect of the pollen viability on different medium, temperature and light quality also were carried out to investigate.The main results were as follows:1.Under nature conditions, the floral bud differentiation lasted about 39 days. The flower bud formation process is divided into seven periods of day-neutral strawberry:Undifferentiated phase, Initial differentiation phase, Inflorescence primordium differentiation phase, Flower primordium differentiation phase, Sepal and Petal primordium differentiation phase, Stamen primordium differentiation phase and Pistil primordium differentiation phase;2. The contents of carbohydrates, nitrogen compounds are at a high level when the strawberry plants in vegetative state; Entering the reproductive growth, part of soluble sugar and starch are consumed, after that the contents continues to increase. During flower bud formation, soluble protein changes first showing a decreasing trend, after increased and finally decreasing trend; The ratio of C/N is increasing with the flower bud formation; ZR contents continue to increase and ABA content showed a decreasing trend during flower bud formation. The ratio of ZR/GA3 in flower bud formation process has been high, and ZR/IAA increased slowly at the early flower bud formation, then rised rapidly at the late.3. Under natural conditions, there are five inflorescences differentiated. The three inflorescence’s flower bud differentiation is uninterrupted and the differentiation time was September 8th, October 5th and November 14th respectively. After the third inflorescences differentiation, plant enters dormancy. When the dormancy release, the fourth and fifth inflorescences have begun to differentiate. The differentiation time was second years in March 28th and May 8th respectively.4. During inflorescence differentiation phase, plant dormancy makes each substance content changes have obvious turning point, before the plant dormancy soluble sugar, starch and total nitrogen content is increasing. After the breaking dormancy plant resumed vegetative growth, trends for the first decrease, then increase. The increase of the content of ZR, GA3and IAA and the decrease of the content of ABA, to promote the inflorescence differentiation.5. Pollen viability in flowering period is getting the highest,The number of pollen each anthers is about 1.16 x 104; the optimum temperature of pollen germination were 25 ℃,10%～15%sucrose+0.10% boric acid for optimal pollen medium, different light quality(except black) had no significant effect on pollen germination rate.