Study On Induction And In Vitro Plant Regeneration Of Tetraploid Paulownia

Paulownia plant is popular in China, which is a fast-growing tree produced high quality timber and green enviryment. But some problems such as wicths broom occered seriously, large crown and short trunk exist all the time. Recentely, lots of new breeds were cultivated by science and technology workers using normal breed methods which were still unsuitable for the purpose . While new channels must be developed . Tetraploid Paulownia.tomentosa Steud., tetraploid Paulownia. elongata S. Y. and tetraploid Paulownia. fortunei Hemsl. were induced with in vitro colchicine treatment using stems leaves and leafatalks as the materials, while, Tetraloid of Paulownia. tomentosa, tetraloid of Paulownia. elongata and tetraloid of Paulownia. fortunei in vitro regeneration were developed, which would give base to new breeds of Paulownia.The main results are as follows:(1) Liquid-medium method, solid-medium method and double-cultured method were compared, and the result was that the double-cultured method was the best one and leaves were the appropriate material.(2) The appropriate combinations for tetraploid of paulownia induction using leaves were combination A₁B₃D₃ (colchicine 5 mg · L^-1 +treatment time 72 h+pre-culture time 12 d), combination A2B1D3 (colchicine 10 mg ? L"'+treatment time 24 h+pre-culture time 12 d), combination A₃B₃D₁(colchicine 20 mg ·L^-1+treatment time 72 h+pre-culture time 0 d) and combination A₃B₃D₃ (colchicine 20 mg · L^-1+treatment time 72 h+pre-culture time 12 d).(3) Chromosome number of the three kinds of tetraploidy plant was 80 and that of diploid plant was 40. Results of the flow cyometric analysis showed the tetraploid plant present twice higher DNA content than the diploid plant.(4) Leaves of tetraploid seedlings were larger, thicker and greener. The stomata size of tetraploid plants were significantly larger than those of diploid ones, while the frequency of stomata were reduced significantly. In addtion, chlorophyll increased and POD reduced.(5) Regeneration systems of tetraploid P. tomentosa, tetraploid P. elongata and tetraploid P. fortunei were developed. And media of calli induction from leaves of which were MS+0.3 mg · L^-1NAA+14 mg · L^-1BA, MS+0.3 mg · L^-1NAA+8 mg · L^-1BA and MS+0.1 mg · L^-1NAA...