Study On The Relationship Between Flower Bud Differentiation And The Metabolism Of Substances In Blueberry

Northern highbush blueberry ‘Duke',half highbush blueberry ‘Northland',lowbush blueberry ‘Blomidon' were selected as the test material to study the morphological differentiation of flower bud in three blueberry cultivars using paraffin section technology.By taking ‘Northland' as the research object,the content of carbohydrates,seven mineral nutrient elements(N,P,K,Ca,Mg,Fe,Mn)and genetic material in physiological differentiation period and morphological differentiation period was determined,and the changes of these substance as well as the impact on flower bud differentiation of blueberry were evaluated.The main results were as follows:(1)The differentiation of flower buds in blueberry was divided into seven phases,including undifferentiated phase,initial differentiation phase,inflorescence primordium differentiation phase,sepal primordium differentiation phase,petal primordium differentiation phase,stamen primordium differentiation phase and pistil primordium differentiation phase respectively.The time required for flower bud differentiation of different varieties is different.The morphological differentiation of ‘Northland' flower buds took 57 days,started from August 1 and ended on September 26.The morphological differentiation of ‘Blomidon' flower buds took 47 days,started form July 10 and end on August 25.The morphological differentiation of ‘Duck' flower buds started from August 9 and end on October 4.(2)Soluble sugar and starch in blueberry leaves increased at the beginning of floral bud differentiation and then decreased.In the early stage of morphological differentiation,the content of soluble sugar increased,but the content of starch decreased.The content of starch which converted to soluble sugar declined to provide nutrition for the formation of blueberry flower organ.The accumulated content of soluble sugar and starch was beneficial to forming floral organs of blueberry flower bud differentiation.(3)In blueberry flower bud differentiation,the gradual increased of C/N could promote the formation of floral organs.The growth rate of C/N at undifferentiated phase could be used as an index of percentage of flower bud differentiation,the higher growth rate,the higher percentage of flower bud differentiation.(4)Trace of N and Fe elements promoted the process of flower bud morphological differentiation of blueberry.Phosphorus concentration was beneficial to the process that physiological differentiation transformed into morphological differentiation.Concentrations of Mg and Ca promoted the formation of floral organs,while accumulating a proper quantity of K and Mn were flocked for accelerating flowering.(5)The total nucleic acid content and RNA had a significant increase during flower bud differentiation of blueberry.High levels of RNA/DNA were advantageous to cell metabolism and various floral organ formation.