Research On The Physiological Basis Of ETH And PP₃₃₃ Regulation On Ornamental Characters Of Bougainvillea Spectabilis Willd And The Process Of Flower Bud Differentiation

Bougainvillea spectabilis Willd has strong growth potential and it is breeding and cultivated easily.Meanwhile it has long flowering and unique ornamental characteristics.As the city flower of Shenzhen,Bougainvillea is widely used as potted plant,hanging plant,vertical greening of overpass and other aspects.However,due to the low temperature and rainfall in Shenzhen,as well as artificial management and other reasons,the bracts appear uneven size,inconsistency in flowering and so on,affect the ornamental value and production application of B.spectabilis Willd seriously.In this paper,B.spectabilis Willd ‘Crimsonlake' as research materials.two kinds of exogenous hormones are used as foliar spraying the exogenous hormones are ethyphon(25,50,75,100,125mg/L)and paclobutrazol(100,300,500,700,900mg/L).This paper also explores the effects of exogenous hormones on the ornamental traits and physiological basis of B.spectabilis Willd.At the same time,observe the morphological characteristics offlower bud and its characteristics of the internal anatomy.So the process of flower bud differentiation of B.spectabilis Willd is to make clear and the following conclusions are obtained:(1)Compared with the control,the treatment of 75mg/L ethephon makes the plant initial flowering 5 days in advance,and the control plants florescence prolonged 7 days;When blooming period is coming the number of flowering branches,inflorescence number,flower number all increased by 67.45%,16.02%,14.72% respectively than CK.But it has little effect on the bract area.Paclobutrazol treatment delay both the initial flowering stage and flowering stage,inhibit the plant flower count,inflorescence number,flower number and bract area,and the higher the concentration,the more obvious inhibitory effect.The treatment of 900mg/L Paclobutrazol delayed plant initial flowering 17 days,shortened plant flowering 41 days,and decreased bracts area 65.70%.(2)During the period of flower bud physiological differentiation(after treatment 10 days),low concentration of IAA,GA3,high concentration of ABA,ZR content is beneficial to the flower bud differentiation;in ethephon treatment,treatment of 75mg/L ethephon Significantly promotes the growth of IAA content(P< 0.05),increased 20.29% than CK.In Paclobutrazol treatment,the most significant effect is in the treatment of 100mg/L(P< 0.05).Higher IAA content,low concentration of ABA and ZR content and stable GA3 content in later stage conducive to the formation of flower morphology.Ethephon treatment all decrease the contents of IAA and GA3,and increase the content of ZR.The treatment of 75mg/L can increase the content of ABA,which is increased 9.04% compared with the control.Paclobutrazol treatment all decrease the contents of IAA and ZR,and increase the content of GA3.The treatment 100mg/L content increases the content of ABA.75mg/L ethephon treatment can significantly promote the ratio of ABA/IAA,ZR/IAA,ABA/GA3,ZR/GA3,and promote the B.spectabilis Willd flower bud differentiation.Paclobutrazol treatment inhibites the ratio of ABA/IAA,ZR/IAA,ABA/GA3,ZR/GA3,the higher the concentration,the more obvious the inhibitory effect.(3)Duiring the flower bud differentiation of B.spectabilis Willd(after treatment 10 days),treatment A,B,C,F,G,H can promote the total nitrogen content of leaf obviously,the promoting effect shows that C>A>G>F>B>H;75mg/L ethephon treatment promote the content of soluble sugar and C/N ratio,is good for flower bud differentiation and flowering of B.spectabilis Willd;100mg/L of paclobutrazol treatment promote the soluble total sugar and soluble protein contein obviously,isgood for flowering.(4)According to flower bud formation and differentiation process of growth cone of B.spectabilis Willd,the flower bud differentiation process of B.spectabilis Willd ‘Crimsonlake' can be divided into eight phases: undifferentiation stage,inflorescence primordium differentiation stage,bract primordium differentiation stage,floret primordium differentiation stage,sepal primordium differentiation stage,petal primordium differentiation stage,stamen primordium differentiation stage and pistil primordium differentiation stage;Early differentiation of flower bud changes is not obvious,and then accelerate the speed of differentiation,showing obvious enlargement and expansion.Understanding the exogenous hormones on the ornamental characteristics and regulation of the physiological basis of B.spectabilis Willd through the above research,has been clear about the flower bud differentiation process of B.spectabilis Willd,provide theoretical basis and practical guidance for more effective guidance flowering regulation ang increase the rate of flowering in actual prodution.