Morphometric And Physiological Changes In Branches, Leaves And Flower Buds At Phase Change In Populus Euphratica

In this paper, the different diameter levels of Populus euphratica individuals under the samesite conditions for the study. Field investigation, Physiological and biochemical experiment andstatistical method analysis were conducted to study the flower and heteromorphic leaves occurredand the vertical spatial distribution，the morphometic changes in branches, leaves and lfower buds,the foliage nutrient, physiological and endohormones characteirstics changes in branches andleaves, along with the different diameter levels and canoy levels. The results were as follows:Linear leaves, lanceolate leaves and ovate leaves were appeared from the2size class.Flowers and broadly ovate leaves were appeared from the4size class which beganed to appearfrom the canopy top in turn. Comprehensive analysis showed that a significant positivecorrelation with high proportion and size of lfower and broadly ovate leaves. Meanwhile regionalof lfower were located in the broadly ovate leaves in4-18diameter levels. Analysis showed thatoccurred in broadly ovate leaves are symbols of the morphological characteristics and P.euphratica into reproductive growth at phase change in P. euphratica.With the increase of diameter levels and canoy levels，morphometric changes in branches,leaves and flower buds were showed the stages and levels of changes. There was a significant/very significant negative/positive correlation with each morphometric index of branches, leavesand flower buds，diameter levels and canoy levels. It’s indicated that the number of branches,leaves and flower buds were changing with the stage of individual development at phase change inP. euphratica.With the increase of diameter levels and canoy levels, nutrient, soluble sugar, starch andsoluble protein, endohormonecontents changes in branches and leaves were showed the stages andlevels of changes. There was a signiifcant/very significant negative/positive correlation betweennutrient, soluble sugar, starch and soluble protein, endohormonecontents contents of branches andleave and diameter levels or canoy levels. Comprehensive analysis showed that nutrient, soluble sugar，starch and soluble portein，endohormoneContents contents of branches and leave werechanging with the stage of individual development at phase change in P. euphratica.Correlation analysis showed a significant/very signiifcant negative/positive correlationbetween nutrient, soluble sugar, starch, soluble protein, GA3, IAA, ZR，IAA/ABA，GA3/ABA,ZR/ABA, ZR/IAA of leaves and leaf morphometric. There was a significant negative correlationbetween total nitrogen and organic carbon, soluble sugar，starch soluble, GA3/ABA of branchesand branch morphometric. Comprehensive analysis showed that nutrient, soluble sugar，starch andsoluble protein, endohormonecontents contents of branches and leave had an important role toregulation branches morphological changes at phase change in P. euphratica.According to the emergence of flower buds，P. euphratica developmental stages divided intojuvenile stage (no flower buds with tree diameter below level2) and adult stage(starting at level4，a few flower buds with tree diameter in between4-8levels and abundant flower buds10-18levels), on tree branch for the juvenile stage (no flower buds with1layer) and adult stage (startingat level flower buds and abundant flower buds5-4layer, a few flower buds with3-2layer).4diameter was turning point which was rfom juvenile to adulthood of P. euphratica. Morphologicaland physiological showed branch length, the number of leaves on each branch，C/N and solubleprotein contents of leaves and branches were signiifcantly reduced. ZR/IAA of leaves andbranches, total nitrogen and ZR contents of leaves were significant increased.10diameter wasturning point which was the bud number rfom less to abundant at adulthood of R euphratica.Morphological and physiological showed IAA contents and IAA/ABA of leaves were significantlyreduced. Petiole length, branch diameter, organic carbon contents of branches were significantincreased.2th layer was turning point which was rfom juvenile to adulthood of P. euphratica.Morphological and physiological showed leaf index was significantly reduced. Starch contents ofbranches were significant increased.4th layer was turning point which was the bud number fromless to abundant at adulthood of P. euphratica. Morphological and physiological showed leaf area,petiole length, the number of budes on each branch, organic carbon contents of branches andleaves, starch contents of leaves were signiifcant increased.