Cryopreservation of some wild orchid seeds
Vilaiporn boonyakitjanda and Vimol kwankua
20th Biennial Conference of the ASIAN ASSOCIATION FOR BIOLOGY EDUCATION “Roles of Modern Technologies in Biology Education”. Chiang Mai University. Chiang Mai, Thailand. 27-30 December 2004. Page 26.
2004
บทคัดย่อ
Cryopreservation of some wild orchid seeds
Seeds of four species of wild orchids, Aerides falcata Lindl., Dendrobium cariniferum Rchb.f., Dendrobium heterocarpum Lindl. And Rhyncostylis retusa (L.) Blume, were preserved by dehydration technique using laminar air flow and siliga gel prior to storage in liquid nitrogen at –196°C. The dehydration periods were 30 minutes and 1, 2, 3 and 10 hours for the laminar air flow whereas 30 minutes and 1, 2, 3 and 25 hours were varied for 50-g silica gel. The seeds were then stored in liquid nitrogen for 24 hours before being thawed in water bath at 25°C. For survival tests, they were cultured on a solidified half-strength Vacin and Went medium at 25°C under the 16-hr photoperiod. It was found that the survival rate (%) depended on the dehydration period as well as the orchid species. All seeds, which were stored in liquid nitrogen without dehydration, did not survive when they were cultivated later. The dehydration periods of 1, 2 and 3 hours were considered appropriate for both techniques since the % survival of A.falcata, D.cariniferum and D.heterocarpum seeds ranged from 50% to 100%. However, this was not the case of R.retusa of which the survival rate was highest at 50% after being dehydrated for 10 hours by laminar air flow or 25 hours by silica gel. It souldbe noted that all viable seeds developed into green protocorms within one month, all of which developed into green shoots.