| Zoysia matrella（L.）Merr.,a perennial warm-season turfgrass of gramineous family.Because of its fine texture,good surface quality,strong growth potential and expansion,salt tolerance,and shade tolerance,it is often used in landscaping and urban construction in southern my country.Zoysia matrella is bred through modern breeding techniques such as somatic mutation and genetic transformation.The selection and breeding of Zoysia matrella is inseparable from rapid artificial propagation,and it is necessary to establish an efficient regeneration system.Embryogenic callus with strong regeneration capacity is an important basis for the establishment of its regeneration system.However,the success rate of callus induction of Zoysia matrella is low,the callus grows slowly,and it is difficult to maintain.In previous studies,with the increase of in vitro culture time and the number of subcultures,the embryogenic callus is easy to degenerate into non-embryogenic and embryogenic callus is also gradually decreasing.It is still a difficult problem to obtain high-quality embryogenic callus.This article mainly studied the effects of four exogenous additives（melatonin,zeatin,epibrassinolide,calcium chloride）on the growth and regeneration of Zoysia matrella callus.Through the analysis of changes in morphological characteristics and physiological indicators,we screened out the concentration and combination of additives suitable for the proliferation and regeneration of embryogenic callus.The main findings are as follows:1.When different concentrations of MT are added to the medium,it was found that 20 mg·L-1is the optimal concentration for exogenous MT treatment to promote callus proliferation,and 15 mg·L-1is the optimal concentration to promote callus regeneration.2.In the subsequent growth of callus treated with different concentrations of single additives,treatment of embryogenic callus at the following four concentrations has the best proliferation effect:20 mg·L-1MT,0.15 mg·L-1ZT,0.01 mg·L-1EBL,10mg·L-1Ca Cl2.The effect of Ca Cl2on the proliferation and growth of callus is not as significant as the first three,and 20 mg·L-1Ca Cl2has an inhibitory effect on the proliferation and growth of callus.When combined with different concentrations of additives,the optimal combination to promote the callus growth of Zoysia matrella is0.15 mg·L-1ZT,0.02 mg·L-1EBL,20 mg·L-1MT,5 mg·L-1Ca Cl2.The embryonic retention of the callus treated with the combination of additives is better than that of a single additive,which is beneficial to the establishment of the regeneration system of Zoysia matrella.3.In the regeneration culture of callus,the effects of a single additive on callus regeneration from good to poor are as follows:0.15 mg·L-1ZT,0.02 mg·L-1EBL,15mg·L-1MT.When treated with different additive combinations,Ca Cl2did not promote the regeneration of callus.0.15 mg·L-1ZT,0.02 mg·L-1EBL,15 mg·L-1MT is the best concentration combination,at this time,the regeneration rate of callus is higher,and the growth of regenerated roots is better.4.In 0-4 weeks of callus regeneration culture,the callus treated with 15mg·L-1MT,0.02 mg·L-1EBL and 0.15 mg·L-1ZT had significantly lower POD activity than other treatment groups at the fourth week.The activity of SOD was higher than that of other groups,and the rate of change of CAT and POD activity was significantly higher than that of other treatment groups.It indicates that the strength of its regenerative ability can be predicted in advance by measuring the level of antioxidant enzyme activity and the rate of change.So as to improve the efficiency of cultivating regenerated seedlings,and further improve the high-efficiency regeneration system of Zoysia matrella. |
