| In this study,Youqiao2?lodging-tolerant cultivar,YQ2?,Ningqiao1?moderate lodging resistance?and Ukraine daliqiao?susceptible varieties,UD?as test materials,useing 4 different concentration of uniconazole(T1,40 mg·L-1,T2,60 mg·L-1 T3,80 mg·L-1 T4,100 mg·L-1)and 4 different concentration of gibberellin(T1,10 mg·L-1,T2,20 mg·L-1 T3,30 mg·L-1 T4,40 mg·L-1)and a water control?T0?to study the effects seed soaking of different concentrations of Uniconazole and GA3 on lodging behavior,yield and yield components,snapping resistance,morphological characteristics,structure of anatomy and lignin content and lignin key enzyme activity and lignin synthesis of key enzyme genes which including PAL,CCR,4CL,C4 H,COMT and CCOAOMT of flooming stage in common buckwheat,and the correlation between lodging behavior and stem characteristics.The main results are as follows:1.Uniconazole and gibberellin effect on buckwheat lodging.Under the condition of Soaking with clear water,the lodging rate,lodging grade and lodging index of the lodging resistant cultivar YQ2 were the smallest,and the UD of the lodging resistant cultivar was the largest,and the middle lodging resistant cultivar NQ was between the two.After soaking,with increasing concentration of Uniconazole,the lodging grade,lodging index and lodging first decreased and then increased in T3 treatment(80 mg L-1)to the minimum value,with the increase of GA3 Concentration,lodging grade,lodging index and lodging first increased and then decreased,at T7(30 mg L-1)reached the maximum value.Therefore,Uniconazole can effectively reduce the probability of lodging,while gibberellin promotes lodging.2.Effect of soaking treatment with Uniconazole and Gibberellin on yield.The yield of three varieties were YQ2 > NQ > UD,Uniconazole and gibberellin,yield per plant,grain number,grain weight per plant and 1000 grain weight increased under T1-T4 treatment and then decreased,and reached the maximum value in T3;in the T5-T8,first increased and then decreased,issued minimum the value in T7 or T8?mostly in T7?.The number of the main stem and the number of branches were opposite to the yield.3.The dynamic changes of indexes related to effects of buckwheat lodging resistance.From the flowering stage to mature stage,three varieties under the control of the plant height,stalk height,fresh weight,stem weight of second internode length and internode diameter of second;mechanical tissue layers,mechanical tissue thickness and the number of vascular bundles;lignin content;soluble sugar content,C/N ratio increased.Snapping resistance parameters;the second internode dry weight and internode filling degree;stem wall thickness and vascular area;PAL and CAD activity changes with increased first and then decreased during the filling stage,and reached the maximum value;4CL activity,POD activity and the content of total N from flowering to filling stage decreased gradually.Among them,the second internode length and the total N content in the period were the largest in the UD,NQ in the second,the smallest in the YQ2,the other indicators were the largest in YQ2,the smallest in UD,and between the two.4.Soaking treatment with Uniconazole and gibberellin could significantly affect the stem resistance of buckwheat.Uniconazole treatment significantly increased the resistance of buckwheat stalk,stalk T1-T4 under flexural strength increased first and then decreased,the maximum value in T3.And reduced the resistance of gibberellin stalk of sweet buckwheat stalk,T5-T8 under flexural force decreases first and then increases,in the T7 issued a minimum.5.Culm morphological index of common buckwheat have significant changes in different concentrations of Uniconazole and GA3 treatment.The plant height,stem height of center of gravity,fresh stem weight and second internode length with increasing Uniconazole concentration,decreased first and then increased,the minimum in T3;the second internode stem diameter,internode second,internode filling of dry weight with increasing Uniconazole concentration,increased first and then decreased,at T3 the maximum value;and changing trend of Gibberellin Treatment trends and Uniconazole on the contrary.6.Changes of anatomical structures of stems under soaking treatment with Uniconazole and gibberellin.Uniconazole,buckwheat stalk stem anatomical index structure?mechanical tissue layer,mechanical tissue thickness,stem wall thickness,the number of vascular bundles and vascular bundle area?were higher than T0 significantly increased,increased firstly and then decreased at T3,and reached the maximum value;but the gibberellin treatment,and mechanical tissue thickness vascular area compared with T0 decreased,increased firstly and then decreased,and the minimum in T7,but the mechanical tissue layers,stem wall thickness and the number of vascular bundles and T0 showed no significant difference.7.Effects of soaking treatment with Uniconazole and Gibberellin on carbon and nitrogen metabolism of stems.Compared with T0,Uniconazole soaking can significantly increase the content of soluble sugar and C/N in stem ratio,reduce the total content of N,with increasing Uniconazole concentration,soluble sugar content and C/N ratio decrease after the first increase,reaching the maximum value at T3,the total N content decreased first and then increased,reached the minimum at T7 value.Contrary to the trend of gibberellin treatment.8.Changes of lignin content and lignin synthesis key enzyme activity under the treatment of Uniconazole and gibberellin soaking.Uniconazole soaking can significantly improve buckwheat stalk lignin content and related enzyme activities.The lignin content and the relative enzyme activity increased first and then decreased with the increase of Uniconazole concentration,and reached the maximum at T7.Compared with T0,the use of gibberellin reduced lignin content and PAL,4CL and CAD activity,but increased the activity of POD enzyme.The content of lignin,PAL,4CL and CAD activity decreased first and then increased with the increase of gibberellin concentration,and reached the minimum value at T7.The activity of POD increased first and then decreased,and reached the maximum at T7.9.Changes of key enzyme genes in lignin biosynthesis.In contrast,the expression of PAL,CCR,4CL,C4 H and CCOAOMT were higher in YQ2 than in NQ,NQ was higher than UD.The expression of COMT was highest in UD,the smallest in YQ2,and NQ in between.After Uniconazole treatment,the expression of key enzymes of lignin synthesis in addition to COMT was significantly increased,and the expression of COMT was decreased.Compared with T0,the expression of PAL,CCR,4CL,C4 H and CCOAOMT increased first and then decreased,and reached the maximum value at T3,which decreased first and then increased in T5-T8,and the minimum value was obtained in T3 or T4 treatment.After treatment,the change trend of each index was contrary to the trend of each index.In summary,Uniconazole and Gibberellin has a significant effect.on lodging habit,buckwheat yield and yield components,mechanical properties,morphological characteristics,anatomical structure,sugar metabolism,lignin content and lignin synthesize key enzymes activity and lignin synthesis key enzyme gene expression When Uniconazole Solution Concentration of 80 mg L-1,the optimization effect of buckwheat stalk is the most obvious,so in this concentration,the optimal stem shape and mechanical strength of the strongest and most metabolism of lignin,buckwheat can increase the lodging resistance,reduce the probability of lodging occurrence,increase production. |
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