| The northeastern region has a special geographical environment.It is long and cold in winter,short and warm and wet in summer.There are fewer species of plants that can survive winter in the open fields of Northeast China.Scutellaria regeliana Nakai,naturally distributed in the northeast region,is a perennial herb with purple flowers.It is an excellent wild ornamental plant,which can be used as a ground cover in gardens.In this paper,the bud regeneration system and the callus regeneration system were established,and the effects of exogenous Methyl Jasmonate on Scutellaria regeliana Nakai under drought stress were studied.The effects of exogenous application of Methyl Jasmonate on physiological and biochemical characteristics of Scutellaria regeliana Nakai under drought stress were also studied,which provided theoretical support for the development and application of wild resources of Scutellaria regeliana Nakai on the basis of proper protection and garden application in arid areas.The main findings are as follows:1.Optimum stem sterilization method and sampling period of Scutellaria regeliana Nakai as explants:the best disinfection method was 75%alcohol 15s+0.1%HgCl2 for 5 minutes,the lowest contamination rate was 8.25%.April was the best time for extracting explants of Scutellaria regeliana Nakai,and the differentiation rate could reach 88.89%.2.Establishment of regeneration system of buds and stems of Scutellaria regeliana Nakai:MS medium was the basic medium suitable for the induction of axillary buds of Scutellaria regeliana Nakai,and then the growth condition of explants was better.The optimal medium for axillary bud germination of Scutellaria regeliana Nakai was MS+1 mg/L6-BA+1 mg/LNAA,the differentiation rate could reach 73.66%;the optimal medium for bud multiplication was MS+1 mg/L6-BA+0.5 mg/LNAA,the multiplication ratio of buds was 5.85;the optimal rooting medium was 1/2 MS+0.2 mg/LIBA,the rooting rate could reach 74.07%;When planting,it was found that vermiculite:perlite:the proportion of garden soil was used in a volume ratio of 1:1:3,and the survival rate of transplanting was up to 79.24%,And the plants grew vigorously.3.Establishment of callus regeneration system of Scztellaria regeliana Nakai:the best disinfection method of leaves was 75%alcohol 15s+1%NaCIO for 5 minutes,with the lowest pollution rate of 20%;the best medium for inducing stem callus was MS+1 mg/L6-BA+1 mg/L2-4D,with the induction rate of 91.33%;when the leaves of Scutellaria regeliana Nakai were used as explants,no callus was induced in all treatment groups.For the phenomenon of browning in the process of callus proliferation of Scutellaria regeliana Nakai,it was found that the medium with 0.5g/L carbon powder was added,the browning rate of callus was 24.44%,and the highest survival rate was 75.56%.The best medium for callus proliferation was MS+2 mg/L6-BA+0.5 mg/L2-4D+carbon powder 0.5g/L,and the highest multiplication multiple was 3.29.The best medium for callus differentiation of Scutellaria regeliana Nakai was MS+1 mg/L6-BA+0.5 mg/LNAA,the differentiation rate was 44.71%.4.Effects of methyl jasmonate on photosynthetic characteristics of Scutellaria regeliana Nakai under drought stress:Exogenous application of methyl jasmonate enhanced net photosynthetic rate,stomatal conductance and transpiration rate of Scutellaria regeliana Nakai,and mainly promoted them.The concentration of intercellular CO2 was decreased,and the effect of MJ4 treatment on Photosynthetic indexes was the most significant.5.Effects of mernyl jasmonate on physiological indices of Scutellaria regeliana Nakai under drought stress:After different concentrations of methyl jasmonate were applied,the content of free proline in the treatment group closed to CK at 1 and 3 days,but it was lower than CK at later treatment time,which indicated that methyl jasmonate could effectively inhibit the increase of free proline content.Thereby alleviating the adverse effects of drought stress on Scutellaria regeliana Nakai.Soluble protein content tended to be lower or lower than CK in the first 6 days of treatment,but significantly higher than CK in the treatment at later time,indicating that methyl jasmonate takes a long time to cause the increase of soluble protein content.In this study,exogenous application of methyl jasmonate could increase the activity of SOD,POD and CAT as a whole,but the effects of different concentrations were different.PPO activity was also higher than CK.Exogenous application of methyl jasmonate promoted PAL of Scutellaria regeliana Nakai as a whole.The results of photosynthetic parameters and physiological indexes of Scutellaria regeliana Nakai showed that the treatment of methyl jasmonate could effectively alleviate the adverse effects of drought stress on Scutellaria regeliana Nakai,but the time and concentration of the most significant effects on Photosynthetic and physiological indices were not the same.Among them,the 9d MJ4 treatment group had the most significant effect on the photosynthetic indexes of Scutellaria regeliana Nakai,while the treatment time with the most significant effect on physiological indicators was 12d. |
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