The Study On Tissue Culture Technique Of Small Leaf Varieties-'Cha Wan No.3' In Dongting Mountain,suzhou

Dongting Biluochun green tea is one of the top ten famous tea in China.It has a long history.Its unique quality characteristics have important relationship with the planting environment,processing process and tea variety in Dongting Biluochun.In this paper,we mainly studied the selection of excellent varieties of Biluochun in Dongting,and then carried out tissue culture experiments to provide germplasm resources support for the future expansion of production.The main contents of this study were as follows:1.Investigation on the excellent germplasm resources of tea tree in Dongting Mountain:20 excellent individual plants were preliminarily selected in the course of the study.Further analysis of botanical characteristics,phenology,fresh leaf quality and biochemical composition was carried out,and the soft leaves were selected according to the botanical characteristics.According to the phenological period,the best product line was Cha Wan system and the Buddhist brocade line.According to the bud density and the weight of 100 buds,the varieties above 6 g were excluded.Finally,the best product species of' Cha Wan No.3' was selected according to the phenol-ammonia ratio.The suitable individual plant was selected for subsequent tissue culture.2.Tissue-culture technique of "Cha Wan No.3":in the tissue culture experiment,it was divided into three stages:primary culture,subculture and rooting culture.Different genotypes,different parts and different time were set up in the experiment.Effects of different disinfectant combinations and different proportion of plant growth agents on the establishment of explants.According to the experimental data,the best explant of'Cha Wan No.3 'tea varietywas the stem segment of axillary buds with leaves during the initial culture period,the best selection time was from April to May in spring,and the best combination of exogenous hormones was MS 6BA2.0mg/L NAA 0.5 mg/L.The best culture and disinfection method for explant anti-browning in spring was 2%sodium hypochlorite(10 min)0.1%mercuric acid(0.1%)for 8 mins and sheltered for 12 hours.In the explant multiplication culture stage,the optimum multiplication culture combination of'Cha Wan No.3 'tea stem segment was MS 6-BA3mg/L NAA 0.25 mg/L,adding 5%sucrose concentration and 4mg/L concentration of gibberellin.In the rooting stage of explants,strong seedlings were cultured best in the medium without any growth regulator after soaking the base 5min of tea plantlets in the solvent of IBA high concentration 2.0mg/L.The optimum carbon source of callus was sucrose.When the NO3-/NH4+ ratio was 2:1,the content of tea polyphenols in callus was the highest.The study can provide excellent tea varieties for tea production and processing,and protect the germplasm resources of small leaf species of Biluochun population in Dongting by tissue culture technology.