| Acacia trees belongs to Leguminosae,Mimosaceae.It is mostly an evergreen tree and has many good properties such as fast-growing,high yield,low tolerance,and nodules nitrogen fixation.The source of high-quality furniture and high-quality pulp,the good ecological and economic benefits make it gradually play an irreplaceable role in forestry production and ecological environment construction.At present,research on the breeding techniques of Acacia tree species in China mostly focuses on tissue culture and cutting propagation.The problems such as low callus induction rate and difficulty in rooting cause its lack of effective breeding techniques,which makes the utilization rate of seed varieties low and can not meet the market.Demand.Therefore,it is of great significance to open up a new breeding route to promote the application of Acacia superior clones and to exert their good value.In this paper,Acacia melanoxylon and Acacia cincinnata were used as materials to systematically study the methods of grafting,the diameter of the rootstock,the location of the scions,the type,concentration,and treatment time of exogenous hormones.The effect of grafting effect of Acacia mangium and the changes of nutrient content and activity of oxidases in the two kinds of scion in the process of grafting healing were analyzed to reveal the physiological changes of Acacia melanoxylon and Acacia cincinnata grafting.The main findings are as follows:1.Comparative experiments of grafting Acacia melanoxylon and Acacia cincinnata grafted in different environments by various grafting techniques in different seasons,comprehensive analysis of survival rate and growth index under various treatments and comprehensive evaluation.The results show that the grafted Acacia in spring is overall The effect was significantly better than that in autumn,and the effect of grafting Acacia melanoxylon on nursery plots was significantly better than that on nursery plots.The survival rates were 41.12%and 58.89%,respectively.2.Different grafting methods had significant effects on the grafting effects of two kinds of Acacia,comprehensively judging the survival rate,growth volume and other indicators.The effect of Acacia cincinnata side grafting method was significantly higher than that of the cutting method,and the average survival rate was 46.67%;Acacia melanoxylon leaves best effect with side grafting method with an average survival rate of 70%.3.The diameter of the rootstock had a significant effect on the grafting effect.The survival rate of Acacia cincinnata tuberculosis was the highest in the range of 9～12mm in diameter,and the comprehensive evaluation of the growth amount was 1.25.The Acacia melanoxylon was in the range of 15～30mm in the thickness of the rootstock.It is more conducive to graft survival,the survival rate is 56.67%,and the comprehensive evaluation for growth is 1.63,which is significantly higher than the rootstocks in the remaining two diameter ranges.4.Acacia cincinnata to select the middle semi-woody shoots as scion,the grafting survival rate is the highest,reaching 40%,and after grafting to survive,the growth of new shoots is better;among the three scions,the upper shoots are scions The survival rate of Acacia melanoxylon was the highest,the average survival rate was 50%,and the combined assessment value of growth was 1.51.5.Three concentrations of 50 mg·L-1,100 mg·L-1,and 200 mg·L-1 of three exogenous hormones,IAA,IBA,and GA3,were set by orthogonal test of L9(34),followed by dipping for 1 second and soaking for 1 minute.,Soaking for 10min three kinds of treatment time,found that each treatment had a significant effect on the grafting effect.The optimal treatment of grafted Acacia cincinnata was to soak the scion with 50 mg·L-1 IBA for 1 min,and the average survival rate was 66.67%.The optimal treatment for Acacia melanoxylon grafting was dipping 200 mg·L-1 IBA for 1 second.The highest graft survival rate reached 73.33%.6.The increase of nutrient content is helpful for grafting healing.During the healing process of Acacia melanoxylon and Acacia cincinnata,the contents of soluble sugar and soluble protein increase first and then decrease.It may be due to the fact that in the initial stage of grafting,in order to promote the formation of callus,it is necessary to call for nutrients in the body to provide a large amount of energy substances needed for graft healing.The soluble sugar content and soluble protein content in scion of Acacia cincinnata variabilis were higher than that in Acacia melanoxylon.japonica in the whole healing process,and its survival rate was also higher than that in Acacia melanoxylon.7.The activities of peroxidase(POD),catalase(CAT),and superoxide dismutase(SOD)increased at the beginning of Acacia melanoxylon and Acacia cincinnata,which played a protective role in the grafting interface.There were two peaks in POD activity and SOD activity of Acacia cincinnata,respectively,at the 20th and 40th days after graft healing,indicating that these two peaks were the two stages of Anoectochondial graft healing,namely callus formation period and callus.Differentiation period.With the formation of callus,the activity of the three decreased compared with before,and the activity of PPO began to increase.It can regulate plant growth and also play an important role in the accumulation of lignin in the healing process. |
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