Study On Tissue Culture And Propagation Of Dominant Moss In Baiyun Obo Mining Area

Due to perennial mining activities in the Baiyun Obo mining area,the ecological environment of the mining area and its surroundings has deteriorated year by year.Investigation found that bryophytes are the dominant plant species in the Baiyun Obo mining area.They can absorb and enrich heavy metals including rare earth elements,which are significant to improve the fragile ecosystem of the mining area.However,the coverage area and biomass of bryophytes under natural conditions are very small,severely limiting value in use.In this project,the gametophytes of Bryum caespiticium and Didymodon constrictus,the dominant moss species in the Baiyun Obo mining area,were used as experiment materials to explore their tissue and rapid propagation systems,The optimal culture conditions were also screened out to expand their reproduction numbers,so as to lay the foundation to apply their various ecological functions.The main findings are the following:(1)Treating three kinds of disinfectants with 75%ethanol,1%Na Cl O,and0.01%Hg Cl₂for 30 s is the best disinfection method for Bryum caespiticium.The pollution rate is zero,and the survival rate is 48.9%;The three disinfectants were treated respectively for 30 s,10 s,and 30 s as the best disinfection method for Didymodon constrictus,with a zero pollution rate and a 40%survival rate.(2)The optimal conditions of the protonus regeneration system of Bryum caespiticium are:1/2 MS+3.0%sucrose+0.1 mg/L 6-BA(or 0.3 mg/L IBA)under the conditions of 12h/d photoperiod and pH 6.0;the optimal conditions for the gametophyte regeneration system are:16h/d photoperiod,pH 6.0,1/2 MS+3.0%sucrose+1.0 mg/L 6-BA+0.5 mg/L IBA.(3)The optimal conditions for the protonus regeneration system of Didymodon constrictus are:MS+3.0%sucrose+0.1 mg/L NAA(or 1.0 mg/L 2,4-D)under the conditions of 12h/d photoperiod and pH 6.0;The optimal conditions for the gametophyte regeneration system are:1/2 MS+1.5%sucrose+0.5 mg/L 6-BA+0.3mg/L IBA under the conditions of 12h/d photoperiod and pH8.0.(4)The growth and development processes of Bryum caespiticium and Didymodon constrictus are similar.The explants with incisions first develop the protons in the medium,and then the protons branch to form the green filaments,and finally the Buds with inconspicuous stem and leaf differentiation growing on the main shaft,which gradually develops into mature gametophytes.(5)In the soil experiment of two kinds of mosses with different substrates,the substrates using vermiculite have the max plant density,plant heights,and number of leaves in the early growth stage(two weeks)of Bryum caespiticium.In the late growth period(one month),the plant density and the number of leaves were not significantly different in different substrates.The Plant height was much larger when grewing on the peat soil or peat soil with vermiculite 1:1.For Didymodon constrictus,vermiculite is the most suitable substrate.This research has successfully established a reproduction system for Bryum caespiticium and Didymodon constrictus.It is expected to provide an ideal material for vegetation restoration in arid and degraded mining area ecosystems in Bayan Obo district.It can also be used for heavy metal pollution monitoring in other mining areas,soil remediation,gardening landscaping,and other applications and research,and can help to protect the existing wild moss resources from destruction by excavation.