The High-frequency Induction of Adventitious Shoots and Plant Regeneration from Leaf Explants of Phalaenopsis with Added Thidiazuron

The effects of different genotypes,plant growth regulators(PGRs) combination,leaf size and dark treatment on adventitious shoot formation and plant regeneration from leaf explants of Phalaenopsis with thidiazuron(TDZ) added were studied.The difference in the induction rate of adventitious shoots among different genotypes with same induction conditions was significant,for example,the ’Red Angle’ was the highest,up to 81.5%,Doritaenopsis Shannong ’Lassie’ and one other were 0,Doritaenopsis Queen Beer ’Red Sky’ and two others were up to 9.2%-34.9%.The adventitious shoots induction rate under TDZ treatment was significantly greater than that in the 6-BA with the same genotype.The adventitious shoots induction rate with 6-BA or TDZ added alone was superior to the combination of 6-BA or TDZ with NAA.When the leaves were younger,the adventitious shoots induction rate was higher.Short dark treatment was propitious to highly significant on adventitious shoot formation.Using 1-2 cm leaves as material,with 15 days of dark treatment and the 3 mg/L TDZ treatment in 1/2 MS culture medium,the explants induction rate and average number of adventitious shoots of ’Red Angel’ reached 100% and 18.2,respectively.This study showed that bud elongation was obviously inhibited by TDZ treatment in subculture medium.