A Study On Micropropagation Of Phalaenopsis Species

The genus Phalaenopsis (Orchidaceae ) comprises a number of commercially important species that have produced a wide range of attractive cultivars or hybrids. Phalaenopsis has long been used in cut flower and potted-plant industries due to its wide variation of flower color and shape. In China, the market for Phalaenopsis has been rapidly expanded and there are about fifty industries to compete for it, but techniques for micropropagation lag behind.In this experiment, inflorescence stalk buds of a Phalaenopsis hybrid "mini red" was used as explants on the developing media to get shoots from which several adventitious buds (ads) were induced at the basal part of it on the proliferation media. The new shoots developed from the ads were used, in turn, to proliferate more new shoots. In this way, bulk of shoots were obtained from a single floral stalk buds with an exponential rate of 4. Furthermore, the effects of supplements such as 6-BA, 2,4-D, IAA, NAA, sugars, PVP and size of shoots on the clonal proliferation of shoots were observed. In addition, immature leaf segments from the above mentioned shoots were used for inducing protocorm-like bodys (PLBs). The effects of TDZ, 6-BA, KT ,coconut milk (CM), lighting and explant orientation on the formation of PLBs were aslo examed.On the media supplemented with 6-BA(10mg/L), not only were the number of shoots multiplied most but also the shoots were stronger than that on the media with other concentrations of 6-BA. 2g/L PVP prompted the proliferation of shoots, but 2,4-D, IAA inhibited shoots multiplication. On the basal media supplemented with 6-BA(10mg/L) and low concentration of NAA (0.2mg/L), the shoots formation was prompted. Glucose (20mg/L,30mg/L) was the best carbon source for shoots proliferation while fructose and sucrose but not mannose were better. Shoots with a size of 1-1.5cm were the most suitable for the proliferation of new shoots. Generally four or five shoots could be obtained from one in every progagation cycle.For leaf segment culture, TDZ was more effective than 6-BA in stimulatingformation of PLBs on leaf segment. CM in media played a beneficial role for PLBs formation. The capability of PLBs formation on leaf segment was higher than that on the young whole leaf. The adaxial-side-up orientation of whole leaf and segment had a significantly higher PLBs formation than that in abaxial-side-up orientation. In darkness. PLBs were easier to be induced than in lighting. Two media were found to be suitable for PLBs formation. The one is that supplemented with TDZ(1mg/L) and 10g/L CM but without sucrose, the other one is that with TDZ(1mg/L) and 2.4-D(lmg/L) in which 2% sucrose played a beneficial role.