The Effect Of BR On The Reproductive Performance Of Leymus Secalinus

Leymus secalinus is a drought-rooted herbage of the Leymus Hochst,with developed rhizomes,strong sand-fixation capacity,strong stress resistance and rich nutritional value.It is a high-quality herbage for biological improvement in saline-alkali land.At present,Leymus secalinus has a low seed yield and low germination rate,which seriously restricts its application in production.The low seed yield was mainly due to the large amount of hollow seeds and small grain weight,which not only affected the seed yield,but also restricted the germination of seeds.Therefore,filling seeds and increasing grain weight can not only increase yield,but also promote seed germination and seedling construction.BR has a regulatory effect on plants,can increase grain fullness,improve 1000 grain weight.In this experiment,Leymus secalinus.CV.Yanbei was used as the test material,and brassinolide(BR)was sprayed at heading stage and flowering stage respectively,and the whole plant was sprayed,divided into four spray concentrations,is 0、0.05、0.1、0.15mg·L-1.The photosynthetic parameters,chlorophyll content,fluorescence parameters,dry matter,sugar metabolism,starch content and the activity of key enzymes in starch synthesis of Leymus secalinus leaves were determined to study the effect of BR on the reproductive performance of Leymus secalinus seeds.Results are as follows:(1)The Pn,Ci,Tr and Gs of Leymus secalinus leaf increased first and then decreased with the increase of BR spraying concentration,when the concentration was 0.1mg·L-1,it reached the maximum value and was significantly higher than the control(P<0.05),The results showed that BR could enhance the photosynthetic activity of the leaves.(2)The content of soluble sugar and sucrose in the leaves of Leymus secalinus increased to the maximum at the concentration of 0.1mg·L-1,which was significantly higher than that of the control group(P<0.05),and flowering stage>heading stage.(3)The enzyme activities of SS and AGPase on Leymus secalinus seeds were increased,and were significantly higher than the control at 0.1mg·L-1 concentration(P<0.05),and flowering stage>heading stage.(4)(4)The starch content,dry matter of the ear and dry matter of the plant increased in the seed of Leymus secalinus.When the concentration was 0.1 mg · L-1,the maximum value was reached,and spraying at the flowering stage> spraying at the heading stage.(5)The panicle length,node number per panicle,floret number per panicle,grain fullness and 1000-grain weight of Leymus secalinus all increased,and reached the maximum at the concentration of 0.1mg·L-1,and flowering stage >heading stage.Seed fullness and 1000-seed weight were significantly higher than the control(P<0.05).In summary,spraying BR with a concentration of 0.1mg·L-1 during the flowering stage of Leymus secalinus can increase the photosynthesis of Leymus secalinus,increase the sugar content of leaves,increase the activity of key enzymes in starch synthesis,and increase the starch content of seeds.Seed fullness,increase 1000-grain weight.