S04 - Session P1 - New Tools II - Effect of Plant Growth Regulators on In Vitro Seedling Growth of Papilionanthe hookeriana (Rchb.f.) Schltr

Authors: Nattaya Montri *, Kanokporn Bunya-atichart

The effect of plant growth regulators on Papilionanthe hookeriana ( Rchb.f .) Schltr . growth was evaluated. Immature seeds from green pods of P. hookeriana were cultured on Vacin and Went medium (VW, 1949) and 2 leaf stage seedlings were cultured on VW medium supplemented with cytokinins (TDZ, BA and kinetin) or auxins (IAA, IBA and NAA) at concentrations of 0, 0.5 and 1.0 mg/L and 0, 2 and 4 mg/L, respectively, for 2 months. The preservation was also investigated for 12 months by culturing 5 leaf stage seedlings on VW media supplemented with plant growth regulators ( ancymidol , paclobutrazol; PBZ and Chlomequat Chloride; CCC) at 0, 5 and 10 mg/L. Five leaf stage seedlings were mulched with sphagnum moss and acclimatized in pots, with coconut husk chops and peat moss used as substrate and compared with control (without substrate) for 2 months. The results showed that, adding cytokinins and auxins at 0-4 mg/L, 4 mg/L of kinetin treatment had the maximum root number at 3.40 roots, while 2 mg/L IAA treatment had the highest leaf dry weight percentage at 5.5 %. Application of 3 plant growth retardants could minimize growth of seedlings and the seedlings height was lowest in 10 mg/L CCC treatment. Mulching root with sphagnum moss and acclimatized in the pot without substrate or with coconut husk chips before transferred to shade house was suitable for the first 2 months of acclimatization with higher survival percentage at 100 and 96.67 % respectively, and seedlings growth was not significantly different between the 2 treatments.