Study On In Vitro Culture System And Rapid Propagation Technology Of Stellaria Dichotoma L.var.lanceolata Bge.

Stellaria dichotoma,the dried root of Stellaria dichotoma(Stellaria dichotoma L.var.lanceolata Bge.),which belongs to the Caryophyllaceae family,is a traditional Chinese medicinal herb endemic to Ningxia.Due to the depletion of wild resources,its medicinal value has led to the development of artificial cultivation of Stellaria dichotoma.However,there are still problems such as mixed seed sources,uneven seed quality,long cultivation cycles for seedlings,and susceptibility to environmental factors.This study focuses on using Stellaria dichotoma as a material to establish an indirect regeneration system between different organs and explore the fast continuous propagation technology of Stellaria dichotoma.The differences in tissue culture and propagation of Stellaria dichotoma from different sources were also analyzed.The main research results are as follows:(1)Establishment of an indirect regeneration system for Stellaria dichotoma.It was found that the optimal medium components for inducing indefinite shoots of Stellaria dichotoma callus were MS+6-BA 2.0 mg/L+NAA 0.2 mg/L+sucrose 30 g/L+ agar 7 g/L,with an induction rate of 95.80%.The optimal formula for the rooting medium for indirect propagation was 1/2MS+NAA 0.1mg/L+IBA 0.6 mg/L+sucrose 30 g/L+agar 7 g/L,with a rooting rate of up to 93.06%.The optimal medium formula for transplantation of regenerated seedlings was perlite+vermiculite+sand+humus=1:1:1:1,with a survival rate of 96.67%.The tissue-cultured seedlings were strong and healthy.(2)Exploration of the fast continuous propagation technology of Stellaria dichotoma.It was found that the optimal medium formula for fast continuous propagation of Stellaria dichotoma was MS+6-BA 2.04 mg/L+NAA 0.27 mg/L+sucrose 18.54g/L,with a growth score of 86.7.The best propagation period was 20 days,and the best propagation effect was achieved by propagating and expanding the 1-4 generations at this time,with healthy and strong shoots,high propagation coefficient,and low browning rate.Bottle-bottom per-rooting technology was used to reduce the rooting period from 40 days to 14 days.The optimal rooting gel formula was Carbomer 940 10 g/L+IBA 1.0 mg/L+6-BA 0.6 mg/L+carbendazim 2 g/L.The optimal medium formula for bottle-bottom rooting was perlite+vermiculite+sand=1:1:1.After 14 days,the survival rate of plantlets was 93.91%,the rooting rate was 76.39%,the average root length was 2.38 cm,and the average number of roots was 3.23.(3)Analysis of differences in fast continuous propagation of Stellaria dichotoma from different sources.Through a comparison of the propagation and rooting effects of Stellaria dichotoma tissue culture from three different sources-greenhouse,wild,and field-significant differences in propagation of tissue-cultured plantlets were observed during 5 times propagation.The growth of greenhouse Stellaria dichotoma plantlets was most vigorous,with a multiplication factor of 3.29～4.02.Wild Stellaria dichotoma was next,while field Stellaria dichotoma had a poorer result.Wild Stellaria dichotoma had the highest growth rate,with a plant height of up to 5.59 cm and a maximum of 8.23 leaves,followed by greenhouse Stellaria dichotoma,while field Stellaria dichotoma had the weakest growth.The browning rate was highest in the field Stellaria dichotoma group,reaching 24.82%,followed by greenhouse Stellaria dichotoma,and the wild group had the lowest.In terms of rooting rate,greenhouse Stellaria dichotoma had the best effect,with a rooting rate of up to 91.67%,which did not decrease significantly in generations 1～5,whereas the rooting rate of wild and field Stellaria dichotoma decreased to below 50%after the third generation,which could not meet the requirements of tissue culture seedling cultivation.In terms of rooting quality,field Stellaria dichotoma had the most roots,with 4.40～3.90 roots in generations 1～5,while the differences in greenhouse and wild Stellaria dichotoma were not significant.Wild Stellaria dichotoma had the longest roots,with a length of more than 3.0 cm in generations 1～5,followed by field Stellaria dichotoma,which was less than 3.0 cm at the fifth generation.The rooting quality of greenhouse Stellaria dichotoma decreased to less than 3.0 cm in generations 4～5,indicating a poorer rooting quality.Overall,in terms of obtaining materials and the quality of tissue-cultured plantlets,using Stellaria dichotoma cultivated in greenhouses as a source for fast continuous propagation is the most convenient,efficient,and sustainable method.