Effects Of Brassinolide On Lateral Root In Triticum Aestivum And Arabidopsis Thaliana

Wheat(Triticum aestivum L)is one of the major crops and widely cultivated in the world,and the 2016 data of the United Nations Food and Agriculture Organization showed that wheat is the second largest grain only after corn.Besides,our country needs a large number of wheat imports every year to meet domestic demand,so the high yield and good quality cultivation of wheat is very important to China’s agricultural production.Based on the physiological function of lateral roots,the root system structure is likely to be a key to the further improvement of crop productivity.Therefore,the occurrence and development of lateral roots have important agricultural significance.Brassinolide affects plant growth and development as an endogenous influencing factor,and as long as a little change will lead to a serious impact on plant growth and development.The study of BR in wheat is in the initial stage,which limits the application of this important hormone in wheat.At present,a large number of research model systems have been established on Arabidopsis roots,and similar mechanisms to Arabidopsis may exist in gramineous plants to control radially root morphology.And considering the lack of BR related research materials in wheat,it is very important to learn the process and mechanism of wheat lateral root development by referring to Arabidopsis,which count much for plant type breeding of wheat.In this paper,the effects of gradient concentration of brassinolide on the lateral root and apical anatomy of wheat seedling roots were studied.To explore the pathway of BR working in Arabidopsis roots,some Arabidopsis BR related mutants were used,and the results not only provided the basis for the scientific use of brassinolide in wheat production,but also verified and expanded the mechanism of the Brassinolide affecting on the development of plant lateral roots.The main experimental results are as follows:(1)Wheat seedling with different concentrations of BL had no significant effect on the aerial parts,but the root system had a significant response to the concentration gradient BL.Compared with the control,the higher the BL concentration,the more severe the inhibition of the main root length was,and the root tip twisted more severely;for the function of promoting lateral roots of BL,it showed the phenomenon that low concentration promote lateral root number but high concentration inhibit.50 nM is the optimal concentration for growth for that the root is not significantly affected and promoting effect is the best at the concentration.The higher the 50 nM was,the shorter the root length was and the less increased number of the lateral roots on the seminal root was or even the inhibition was observed.(2)BL affected on lateral root primordium initiation directly or indirectly and promoted the formation of root primordia;what’s more,BL functed on root cortex and increased the growth rate of root primordia,leading to the increased number of visible lateral roots.(3)The explore of brassinolide pathway working in lateral root growth in Arabidopsis.BR is a positive regulator of BRS1,which acts on the cortical cells,and it made the lateral root primordia more easily break through the cortex,and accelerated the lateral root primordia to break through the cortex and finally affected the number of lateral roots and the morphology of the root system can be changed by regulating the expression of BRS1.