Mechanism Of The Floral Bud Differentiation And Flowering Regulation Of Cymbidium Sinense 'Qijian Baimo'

Cymbidium sinense is a perennial herb of the Orchidaceae family.Its flower style,pleasant fragrance and elegant leaves make it one of the best ornamental flowers.In this study,we use the C.sinenseas test material,and study the flowering mechanism of C.sinense from the view of‘Qijian Baimo'developmental biology and molecular biology,leading to following results.The process of flower differentiation in‘Qijian Baimo'includes undifferentiated stage,flower bud differentiation and development stage,pedicel elongation stage,small bell stage,large bell stage and flowering stage.‘Qijian Baimo'flower differentiation,which could be divided into six stage including growing point elongation,sepal primordium differentiation,floret primordium differentiation,sepal primordium differentiation,petal primordium differentiation,column and pollen differentiation,mainly includes inflorescence differentiation and florets differentiation,The speed of floral formation of‘Qijian Baimo'is related to the degree of development of floret.Different regulation treatments have different effects on the flower formation of‘Qijian Baimo'.The N:P:K=10:30:20 fertilizer treatment in the experiment was conducive to the elongation and development of flowering branches,the increase of flowering number.Prolonging the light hours to 16 h could advance the initial flowering period of‘Qijian Baimo'.Exogenous plant growth regulators can effectively improve the flower quality of‘Qijian Baimo'and promote flowering.In December,‘Qijian Baimo'were in the stage of differentiation and development,and their flower buds were highly physiologic and metabolically sensitive to external factors.In the test of flowering regulation,100 mg/L6-BA was conducive to elongation and development of flowering pedicels and peduncles,flowers became larger and the early flowering stage was advanced.25 mg/L SA was beneficial to the growth of pedicel,increased the number of flowering and flowering rate and advanced flowering period.In the test treatment,T3?100 mg/L 6-BA+150 mg/L GA₃+100mg/L SA?had the best promoting effect on flowering quality.T6?200 mg/L 6-BA+150 mg/L GA₃+25 mg/L SA?and T8?300 mg/L 6-BA+100 mg/L GA₃+25 mg/L SA?had the best effect on early flowering.The analysis of flowering gene expression at different stages of floral bud differentiation showed that 100 mg/L 6-BA+50 mg/L GA₃ treatment can effectively degrade the flower inhibitory factor DELLA protein,stimulate the expression of SOC1,LFY and AP1genes and promote the production of‘Qijian Baimo'Flowering ahead of time.