Comparative Studies On Regeneration And Cell Suspension Culture In Vitro Among Different Genotypes Of Populus Tomentosa Carr.

Populus tomentosa Carr. is a native species of China. It has played a key role in forestry production and ecological environment construction in north of China. Now, the important problems of Populus breeding are orderly improvement and shortening breeding time. Rapid propagation and in vitro plant gemplasm resources conservation could be implemented by tissue culture. And tissue culture could also provide technical basis for orderly improvement of P. tomentosa. In this study, many good P. tomentosa genotypes were selected as study materials. Studies of aseptic culture, leaf regeneration and cell suspension culture were developed by the technique of tissue culture. The study laid the foundation for genetic transformation and somatic embryogenesis of P. tomentosa. The major results and conclusions are described as follows:1. Different P. tomentosa genotypes were cultured in aseptic conditions by using soft branches as explants. The best sterilization methods of different genotypes were different. The best sterilization method of genotype TC152, TC333 and TC504 was 70% ethanol 30 s+0.01% HgCl₂ 7 min. The best sterilization method of genotype TC121, TC342 TC503, TC510 and TC970 was 70% ethanol 60 s+0.01% HgCl₂7 min. The best sterilization method of genotype TC332 was 70% ethanol 30 s+0.01% HgCl₂ 9 min. The best sterilization method of genotype TC414 was 70% ethanol 60 s+0.01% HgCl₂ 9 min.2. The best propagation media of different genotypes were selected. The best propagation medium of genotype TC121 and TC152 was MS+0.5 mg/L 6-BA + 0.1 mg/L NAA. The best propagation medium of genotype TC332, TC333, TC510 and TC790 was MS+0.7 mg/L 6-BA+0.1 mg/LNAA. The multiplication capacities of different genotypes were different, on the medium of MS + 0.7 mg/L 6-BA + 0.1 mg/L NAA. The multiplication capacities of genotype TC121 and TC152 were best, which could reach to 4.0. The multiplication capacities of genotype TC332 and TC333 were worst, which were only3.0.3. The best rooting medium of different genotypes was selected. The best rooting medium of genotype TC121, TC152, TC332, TC333, TC510 and TC970 was 1/2MS+0.60 mg/L IBA.4. The leaf in vitro regeneration systems were established by using leaves of tissue culture plants as explants. The best regeneration media of different genotypes were selected separately. On the medium of MS+1.5 mg/L 6-BA+0.5 mg/L KT, the regeneration rate of genotype TC121 could reach to 48.45%. On the medium of MS+2.0 mg/L 6-BA+0.1 mg/L NAA, the regeneration rate of genotype TC152 could reach to 97.78%. The best regeneration medium of TC332 was MS+1.0 mg/L 6-BA+0.1 mg/L NAA+1.0 mg/L ZT, the regeneration rate could reach to 98.89%. The best regeneration medium of TC333 was MS+1.5 mg/L 6-BA+1.0 mg/L KT+1.0 mg/L ZT, the regeneration rate could reach to 86.67%. The best regeneration medium of TC970 was MS+1.0 mg/L 6-BA+0.1 mg/L NAA, the regeneration rate could reach to 93.33%.5. The cell suspension culture systems were established by using the calli as explants. The suspension cells could be acquired when the calli of genotype TC152 were in the medium of MS+1.0 mg/L 2, 4-D, the calli of genotype TC332 were in the medium of MS+2.5 mg/L 2, 4-D, and the calli of genotype TC510 and TC970 were in the medium of MS+2.0 mg/L 2, 4-D. The best reproduction medium of the 4 genotypes was MS+0.8 mg/L 2, 4-D. Suspension cells were harvested after the leaves of tissue culture plants being suspension cultured. In the liquid medium of MS+3.0 mg/L 2, 4-D, the suspension cells of genotype TC152 and TC 970 could be harvested after being cultured for 30 d.6. The regeneration of suspension cells were studied by using the suspension cells of genotype TC152. And the regeneration plants were acquired. Large amounts of adventitious buds could be acquired when the cells of TC152 was cultured in the liquid medium of MS+1.0 mg/L 6-BA+0.1 mg/L NAA+0.5 mg/L ZT or MS+1.0 mg/L 6-BA+0.1 mg/L NAA+1.0 mg/L ZT. There would be 40-50 buds in every bottle. The calli which were acquired after suspension cells being cultured in solid medium would regenerate adventitious buds on the medium of MS+1.0 mg/L 6-BA+0.1 mg/L NAA+1.0 mg/L ZT. The regeneration rate was 70.00%. The adventitious buds could root on the medium of 1/2MS + 0.60 mg/L IBA.