Media for seed germination and seedling development of some terrestrial orchids; Habenaria rhodocheila Hance. and Pecteilis sagarikii Seidenf

Habenaria rhodocheila Hance. and Pecteilis sagarikii Seidenf. are beautiful terrestrial orchids, of both their leafy stems and flowers. They could grow as commercial pot plants for indoor decoration. Numerous tubers were collected from their habitat to sell at domestic and foreign plant markets. So, the in vitro seeds propagation must be studied for the purposes of conservation and commercialization. The first experiment was study on the effect of seed surface-sterilizing on seed germination percentage and index. Seeds were sterilized with 10 percent clorox or hydrogenperoxide before sowing in the liquid modified Vacin and Went (1949) (VW) and kept in the dark for 4 months. The result showed that sterilized seeds with clorox and hydrogenperoxide had germination percentage at 78.00 and 77.57 respectively. In addition, the clorox treated seeds showed better development. And the seeds in agitate or non-agitate condition showed no different in germination and development. The second experiment was study on effects of mineral concentration. The H. rhodocheila, and P. sagarikii seeds were sown in liquid VW modified by using 0.25, 0.50, 0.75 or 1.00 strength of VW with 0, 10 or 20 g/l of table sugar or glucose. After 4 months in the dark, the seeds of both species had no significant difference in germination percentage and index in all media. After the seeds were germinated, the white protocorms with 1 or 2 leaves from liquid media were transferred on solid VW modified with 150 ml/l young coconut water, 100 g/l potato extract, comparing with half or full strength of VW with 10 or 20 g/l of table sugar and 0 or 20 g/l homogenized banana. After the incubation in light condition for a month, the seedlings of both species showed green leaves with larger size in all treatments. The third experiment was study on tuber development. When H. rhodocheila seedlings had 2 leaves, 15 mm. height and 2*6 mm in tuber's size. They were transferred to new media. The modified solid VW media were added with 20, 40 or 60 g/l table sugar and 0, 0.001, 0.01, 0.1 or 1 mg/l paclobutrazol. The brown tubers with white root were enlarged after 3 months, but there was no different in the number and size of tubers or roots in all media.