Regulation Of Exogenous 6-BA And GA₃ On The Phenotype Of Quercus Mongolica

Mongolian oak（Quercus mongolica）is a native tree species in the northeast,in the northeast forest area is an important tree species for maintaining the ecological balance of the environment,but also an excellent landscape species,in the landscape has broad applications prospects.Influenced by environmental conditions,low temperatures in winter usually lead to the death of terminal buds and stimulate the development of lateral branches in oak plants.However,the unstable stimulating effect of low temperature in winter will lead to the unstable sprouting of lateral buds and irregular sprouting time of oak plants,which in turn leads to the very unstable construction of oak plants and reduces the ornamental value of their plant morphology.In view of this,this study is intended to find ways to promote the germination of axillary buds of Mongolian oak,so as to achieve the purpose of regulating the plant size of seedlings and enhancing their ornamental value.In the present study,we explored the effects of 6-BA and GA₃ on the regulation of Mongolian oak plant shape through plant physiology and molecular biology by using 1,2 and 3 years old Mongolian oak as experimental materials.The main findings are as follows:1.Effect of exogenous 6-BA and GA₃ on the growth and development of Mongolian oakIn terms of promoting the increase of the number of lateral branches,the effect of GA₃treatment was the most significant when the concentration of 500μM in 1,2 and 3-year-old seedlings;Under 6-BA treatment,the promotion effect was the most significant when the concentration was 600μM in 1-year-old seedlings,and 2000μM in 2 and 3-year-old seedlings;Under the treatment of mixed hormone,the promoting effect was the most significant when the concentration of 6-3M in 1-year-old seedlings and 20-3M in 2 and 3-year-old seedlings.In terms of promoting the elongation of lateral branches,the promoting effect of GA₃ treatment was the most significant when the concentration was 500μM,the most significant effect was when the concentration of 6-BA was 200μM,and that of mixed hormone treatment was 2-1M.In terms of promoting the growth of seedling height,the maximum concentration of GA₃treatment in one-year-old seedlings was 800μM,and the increase in seedling height was the most significant under its treatment.The maximum concentration set in 2 and 3-year-old seedlings was 500μM,and the seedling height increased most significantly under its treatment;Under 6-BA treatment,the promotion effect was the most significant when the concentration of 1-year-old seedlings was 200μM,and that of 2 and 3-year-old seedlings was 2000μM;Under the treatment of mixed hormone,the promoting effect was the most significant when the concentration of 6-3M in 1-year-old seedlings and 20-3M in 2 and 3-year-old seedlings.2.Effect of exogenous 6-BA and GA₃ on endogenous hormone contentIn terms of promoting the increase of endogenous GA₃ content,exogenous GA₃application had the most significant promotion effect on the endogenous GA₃ content of seedlings,the content of endogenous GA₃ increased significantly under 6-BA treatment whose elevation was lower than that of GA₃ treatment,and the increase of endogenous GA₃ content under mixed hormone treatment was lower than that of 6-BA or GA₃ treatment.In terms of promoting the increase of endogenous ZR content,the effect of 6-BA or mixed hormone on the endogenous ZR content of seedlings was similar,and the promoting effect was better than that of GA₃.3.Effects of exogenous 6-BA and GA₃ on transcription factors BRC1 and AHK3BRC1 expression was down-regulated for a period of time after the application of 6-BA and mixed hormones as well as GA₃ treatment.AHK3 expression was up-regulated for a period of time after exogenous 6-BA and mixed hormone treatment,and the expression trend was similar to that of the control treatment under exogenous GA₃ treatment,which did not show a certain pattern.