Physiological And Molecular Mechanism Of Architecture And Flowering For Young Apple Trees Fuji Effected By Dwarf Rootstock M9-T337

Dwarf rootstock exert an important influence on the growth and flowering of apple(Malus pumila Mill)trees.Exploring related physiological mechanisms,it is quite important to expand the pattern of dwarf and high-density cultivation and the intensive study of the scion-rootstock interaction.In this study,dwarf rootstock M9-T337 and Fuji apples were used as test materials,and their distinct growth characteristics differences in tree sizes,the length of young trees and the difficulty of flowering and fruiting were used in this study,by testing the growth of trees,the root growth,the flowering features,the endogenous hormone content,accumulation of mineral nutrients and associated gene expression,Aiming to explore the effect that M9-T337 as a dwarf rootstock posed on the formation of young apple trees flowering.Effects of M9-T337 Dwarfing Rootstocks on the growth of young apple trees as following:1.The decrease of M9-T337 dwarf rootstock to Fuji growth indexes was28.9%-74.5%,which had a significant weakening effect on Fuji tree sizes.2.After being grafted on the dwarf rootstock M9-T337,roots of young Fuji apple trees were changed from its alienated root type to the shallow multi-branch root of M9-T337,which overwhelmingly reduced the proportion of thick roots.3.Under the influence of M9-T337,IAA in Fuji /M9-T337 accumulated in the phloem of rootstocks,and other endogenous hormones in Fuji /M9-T337 were also regulated.4.The expression of genes related hormone in both root and leaf stages of Fuji/M9-T337 is generally between their seedlings.Moreover,the content of IAA is significantly lagged behind the expression of MdYUCCA10 a gene and there is a significant hysteresis relationship between the content of GAs and MdGA20 ox gene expression.Effects of M9-T337 Dwarfing Rootstocks on flowering of young apple trees as following:1.Proportion of Fuji apple trees short shoots increased to promote its flowering afterbeing grafted on the dwarf rootstock M9-T337.The flowering rate increased from 0% to1.4% to 8.7% to 11.3%..2.M9-T337 Dwarfing Rootstocks improve the quality of Fuji apple tree leaves by accelerating the accumulation of organic material in 5-7 months.3.Content of N,P,K and soluble sugar,as well as starch content of Fuji /M9-T337 leaves and short branch terminal bud significantly increased compared with that of Fuji seedlings.M9-T337 dwarf rootstock promoted Fuji flowering by changing accumulation of mineral elements and carbohydrates in plant leaves and short branch terminal bud.4.Being grafted on the dwarf rootstock M9-T337,the content of integration factor s MdSOC1 and MdFT of the ways of flowering regeneration on short branch terminal bud of Fuji,as well as the downstream gene MdSPL9,gene MdTPS1 and MdTPS2 related to sugar synthesis and MdSUSY1 related to glucose metabolism elated genes MdSUSY1 all increased compared with Fuji seedlings.M9-T337 dwarf rootstock changes the rate and mode of the synthesis and transport of hormones,mineral elements and carbohydrates by changing the expression and transmission process of related genes in Fuji apple,and then improve leaf qualities,the proportion of long and short branches and root architecture,which are closely related to the growth of plants.Finally,M9-T337 dwarf rootstock promote Fuji apple trees dwarfing and flowering.