| In order to investigate the effects of different concentrations of PP333,Uniconazole and their combined agents on the phenotypic plasticity of Amorpha fruticosa plants,In this study,annual concentrations of PP333(0mg/L,200mg/L,300mg/L,400mg/L,500mg/L),Uniconazole(0mg/L?100 mg/L,200 mg/L?300 mg/L?400 mg/L)and a combination of PP333 and Uniconazole(S1+D2,S1+D3,S2+D2,and S2+D3,respectively Uniconazole 100mg/L mixed with PP333 200mg/L?Uniconazole 100mg/L mixed with PP333300mg/L?Uniconazole 200mg/L mixed with PP333 200mg/L?Uniconazole 200mg/L mixed with PP333 300mg/L)were applied to annual amorpha seedlings.The optimal concentration of pesticide treatment and optimal combination of PP333,uniconazole and compound agents for regulating plant phenotypic characteristics were obtained It is expected to provide theoretical basis for the wider planting and development of Amorpha fruticosa in Maowusu sandy land.The main conclusions are as follows:(1)PP333 inhibited the growth of above-ground part of Amorpha fruticosa seedlings,but promoted the growth of fine and medium roots of seedlings,which in turn allowed the plant biomass to accumulate,the specific results are as follows:PP333 inhibited the growth of plant height,leaf length,leaf width,leaf area,and crown width of Amorpha fruticosa seedlings.Under the treatment concentration of 300 mg/L,the plant base diameter,branch number,branch base diameter,branch angle,total plant fresh weight,dry weight,and root-shoot ratio all reached the maximum.The root length,surface area and root volume of the fine roots of the plant reached the maximum at a concentration of 400 mg/L.300mg/L treatment concentration had the best promotion effect on all indexes of middle root.According to the principal component analysis,the optimal concentrations of PP333-regulated plant growth indicators were 300mg/L,followed by 200mg/L.(2)Uniconazole treatment inhibited the growth of the aerial part of Amorpha fruticosa seedlings,but promoted the growth of fine and medium roots of seedlings,which in turn caused the accumulation of plant biomass.the specific results are as follows:After treatment with uniconazole,the plant height,leaf length,leaf width,and leaf area were significantly inhibited.With the increase of the treatment concentration,the inhibition was stronger.At each treatment concentration,the crown size of the plant was significantly lower than CK(P<0.05),but with the increase of the treatment concentration,the crown size increased first and then decreased,and 200mg/L had the best promotion effect.In the concentration range of 200mg/L and 300mg/L,the plant base diameter,branch base diameter,number of branches,branch angle and fine and medium roots promote the best effect.With the increase of the treatment concentration,the total fresh weight and dry weight of the plants showed a trend of rising first and then decreasing.According to the principal component analysis,the optimal concentrations of uniconazole to regulate plant growth indexes were 200 mg/L,followed by 100 mg/L.(3)Uniconazole and PP333 combined treatments were similar to the two single-agent treatments,both of which could inhibit the growth of the aerial part of the plant,promote the growth of the plant's fine and medium roots,and the accumulation of biomass.Compared with the effect of the optimal application concentration of two single agents:Under S2+D2 treatment,the plant height and leaf length were the lowest,and the basal diameter,basal diameter of branches,number of branches,root length,root surface area,total fresh weight and dry weight promoted the best effects.Under S2+D3 treatment,the leaf width and leaf area were the lowest,and the branching angle and root volume were the largest.According to the principal component analysis,it was determined that the combination with the best effect on regulating plant growth index was S2+D2. |
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