Analysis On The Factors To Coiling Of Bermudagrass Sod And The Effect Of Auxin On The Grouwth Of Bermudagrass

Lawn is widely used in fields such as garden construction,street greening,saline-alkali land improvement,sand prevention and control,slope and embankment protection.Bermudagrass（Cynodon dactylon（L.）Pers.）is a warm-season turfgrass with fast growth,superior drought tolerance,trampling resistance,soft texture,and good turf color,which is widely used in China and worldwide.Bermudagrass mainly propagates in vegetative stolon,therefore promoting the formation of sod and plant growth is an important industrial issue.In this thesis,the growth characteristics of bermudagrass were characterized and sod forming of bermudagrass using different planting methods,fertilizer combination（including nitrogen,phosphorus,and potassium）,and exogenous auxin spraying.The functional analysis of Cd IAA18 genes was investigated and further application was discussed,which provides a theoretical basis for subsequent research onbermudagrass sod production and grassgrowth and development.The research results are as follows:1.Effect of four cultivation methods on bermudagrass sod formation.Four cultivation methods,including sprinkling,rotary tillage,hole planting,and interlacing were applied for lawn construction.The lawn growth,turf formation,roll formation speed,and quality were evaluated.The results showed that the interlacing method can promote sod formation,the sprinkling method can boost rolling of the sod,and the hole planting method can accelerate the development of the underground parts of the turf,which can improve the quality of the sod roll.In a word,the best way to establish turf is the method of spreading grass stem,and the best way to produce sod roll is the method of burrowing grass stem.2.Effect of different nitrogen,phosphorus,and potassium on bermudagrass sod formation.A three element quadratic orthogonal rotation combination approach was applied as a fertilization treatment scheme.The best treatment combination was T9,with fertilizer content of N:28 g/m²,P₂O₅:14 g/m²,and K₂O:14 g/m².A regression model between the comprehensive quality related to sod and the three factors of nitrogen,phosphorus,and potassium was established.Through simulation and optimization,the optimal formula range of nitrogen,phosphorus,and potassium was screened,namely N:27.656～27.925 g/m²,P₂O₅:18.988～23.208 g/m²,K₂O:16.358～20.777 g/m².In addition,the regression model was used to discover the optimal formula range of nitrogen,phosphorus,and potassium for various turf rolling related traits.The results showed that the optimal fertilization scheme for rapid sod formation is:N:27.501～27.875 g/m²,P₂O₅:13.958～17.945 g/m²,K₂O:9.572～12.194 g/m²;the optimal fertilization scheme for rapid roll formation is:N:25.661～26.285 g/m²,P₂O₅:15.448～17.612 g/m²,K₂O:9.256～1.112 g/m²;the best fertilization scheme for rapid growth of aboveground parts is:N:25.911～26.685 g/m²,P₂O₅:16.347～19.302 g/m²,K₂O:10.313～13.060 g/m²;the best fertilization scheme for rapid growth in underground areas is:N:16.547～21.241 g/m²,P₂O₅:14.333～18.836 g/m²,K₂O:11.570～16.189 g/m²;the best fertilization scheme for faster coverage is:N:27.342～27.734 g/m²,P₂O₅:15.124～18.719 g/m²,K₂O:13.650～16.638 g/m²;the best fertilization scheme with higher color score is:N:23.422～24.071 g/m²,P₂O₅:15.290～17.021 g/m²,K₂O:15.182～16.738 g/m²;and the optimal fertilization formula for high grass block tension is:N:26.061～26.652 g/m²,P₂O₅:15.273～18.112 g/m²,K₂O:18.827～20.891 g/m².3.Selection of the optimum concentration of auxin treatment to promote the growth of bermudagrass root.The results showed that auxin at concentrations of 10^-8to 10^-7mol/L promoted root elongation of bermudagrass during tissue culture,whereas auxin concentrations above 10^-8mol/L promoted root growth in field condition.When bermudagrass stolon cuttings were cultivated in the field,auxin with concentrations at0,1,5,15 and 30μmol/L was applied.The results showed that auxin concentration with lower than 5μmol/L could significantly promote root elongation,while concentration higher than 5μmol/L could significantly increase the root number.4.Functional cloning of Cd IAA18 and possible application.The sequence of Cd IAA18 in auxin pathway was cloned and transfeed heterologously into Arabidopsis thaliana.The results showed that no significant differences were observed in root length,root number and shoot growth between transgenic lines and wild type.In summary,the results showed that different cultivation methods affected bermudagrass sodformation.The method of spreading grass stolons could promote sod formation,the method of burrowing grass stolon accelerate regeneration of sod.Application of N,P and K accelerate sod formation,in which N is dominant,P and K play roles in maintaining good auxiliary effect.Auxin promotes bermudagrass root growth and accelerates the formation of bermudagrass sod formation.The research is of practical significance for the rapid production of bermudagrass sod.