Study On Induction And In Vitro Plant Regeneration Of Autotetraploid P.australis And P.tomentosa×P.fortunei

Paulownia is a very important fast-growing timber species,It is important to plant Paulownia because it not only can solve the problem of the shortage of wood in China but also can improve the ecological environment. However, Because of the disserve of paulownia witche’s broom, caused great losses to the forestry .In recent years, with the rapid development of biotechnology, polyploid breeding has made great achievements which creat a new road for Paulownia breeding. Tetraploid of tetraploid of(Paulownia.tomentosa×Paulownia.fortunei)and tetraploid of Paulownia.australis were induced with in vitro colchicine treatment using leaves as the materials and the system of in vitro plantlet regeneration of tetraploids of(Paulownia.tomentosa×Paulownia.fortunei) and Paulownia australis was established.While study the effection of DNA methylation agent and DNA Demethylation agent to the in vitro plantlet regeneration of the two tetraploids, The main results are as follows: (1)Use double-cultured method induced tetraploid plant of Paulownia,The concentration ofcolchicine and treatment time produced Significant variance to the experiment, pre-culture time not produced Significant variance to the experiment.(2) The appropriate combinations for tetraploid of paulownia induction was combination8(colchicine 20 mg·L-1+treatment time 48 h+pre-culture time 0 d)and combination 6(colchicine 20 mg·L-1+ +treatment time 72 h+pre-culture time 0 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)In vitro plantlet regeneration system for Paulownia autotetraploid is established.Among intemodes,petioles and leaves,leaves were the best explants for vitro plantlet regeneration. The optimal media for callus、shoot and root induction for Paulownia austrl is MS+0.3mg·L-1NAA+12mg·L-1BA, MS+0.3mg·L-1NAA+12mg·L-1BA and 1/2 MS. and For Paulownia tomentosa×Paulownia fortune is MS+0.5mg·L-1NAA+16mg·L-1BA,MS+0.5mg·L-1NAA+16mg·L-1BA and 1/2MS.(6)The effect of MMS and 5-Aza to Paulownia in vitro plantlet regeneration was studied. MMS and 5-Aza could restrain the shoot and root induction for Paulownia autotetraploid.The restrain degree enhanced with the increase of the content of MMS and 5-Aza.Significant variance was found among the different treatment.