Effect Of Colchicine On Seed Germination And Seedling Growth Of Dracocephalum Rupestre Hance

Dracocephalum rupestre Hance was a kind of labiatae wild perennial herbs,possessing higher medicinal and ornamental value.In the northern part of Shanxi Province,Dracocephalum rupestre Hance was processed into "Maojian tea" for drinking by local people.In recent years,with the rapid development of medicinal tea industry in Shanxi,the demand and quality of Dracocephalum rupestre Hance in practical production had higher requirements.So it was imperative to select and breed wild Dracocephalum rupestre Hance resources and germplasm innovation.In this study,seeds was treated with different colchicines,by analyzing the germination indexes of seeds and the seedlings growth under different cultivation methods.Some seeds were cultivated by tissue culture,aiming to provide a technical research basis for colchicines to induce polyploidy of Dracocephalum rupestre Hance.The results of this study were as follows:（1）Under different culture methods: the sequence of germination time was petri dish,culture medium,nutrient soil;the germination rate was petri dish,culture medium,and nutrient soil in descending order.The germination of Dracocephalum rupestre Hance seeds was greatly affected by light,the combination of environmental factors and colchicine affects the germination of seeds.（2）In the petri dish,there were two treatments with higher germination rate: 0.05%-9h,0.10%-9h.The best treatment for germination in nutrient soil was 0.05%-3h.The weakest germination treatment in 1/2 MS medium was 0.20%-9h.（3）The long-term soaking of colchicine caused the radicle of the seedlings to swell and shrink,and the growth and development were stagnant.When cultured in petri dishes,the seeds treated with colchicine were not prone to develop lateral roots,and their survival rate was extremely low.In nutrient soil,seedlings could grow lateral roots,but they grow slowly.In tissue culture,the lateral roots of Dracocephalum rupestre Hance under low concentration and short soaking time could be generated.（4）Colchicine inhibited the elongation of the radicle,long-term soaking was conducive to the accumulation of substances.（5）In the nutrient soil,the stem height of the seedlings after 9h soaking with 0.05%,0.10%,0.20%colchicine was significantly reduced,the crown width all showed different degrees of decline,and the leaf length/leaf width values were compwered with those of the control.It was reduced,but not significantly.（6）The disinfection time of HgCl₂ suitable for Dracocephalum rupestre Hance seeds was 7.5min.At this time,the pollution rate decreased and the inhibitory effect on seed germination was small.（7）The concentration of IBA and NAA had different effects on the growth of the root system and above-ground part of the seedlings of Dracocephalum rupestre Hance.Adding NAA 0.5mg/L had the largest plant height value,adding IBA 0.5mg/L and NAA 0.5mg/L had the largest root length.Hormone concentrations higher than 0.5mg/L caused poor seedling growth.