Effect of cryopreservation on seed germination and protocorm development of Vanda tricolor

Abstract

Germination and subsequent development was assessed after seeds of Vanda tricolor were stored in liquid nitrogen. Mature seeds, harvested 7 months after self-pollination, were directly plunged into liquid nitrogen. Germination of cryopreserved seeds on solid New Dogashima (ND) medium supplemented with 1 mg/l 6-benzyladenine, 0.5 mg/l 1-naphthaleneacetic acid and 2% sucrose was faster than non-cryopreserved seeds (28 days versus 60 days after sowing). Immature seeds, harvested 6 months after self-pollination, were treated with or without loading solution (LS) of 2Mglycerol and 0.4 M sucrose in liquid ND medium, pH 5.4 at 25°C for 15 min and dehydrated with PVS2 solution for 0-210 min on ice and then cryopreserved by vitrification. The results showed that the germination percentage of cryopreserved seeds treated with LS was higher than without LS. After 90 days of sowing, the highest germination percentage of cryopreserved seeds was 13.6% which was higher than non-cryopreserved seeds (10.5%) when seeds were treated with LS for 15 min and then dehydrated with PVS2 solution for 180 min. After 150 days of sowing, protocorms of non-cryopreserved and cryopreserved seeds were able to form new protocorms (budding protocorms) and developed into shoots after 180 days of sowing. There were no significant differences between growth and development of protocorms derived from noncryopreserved and cryopreserved seeds. Copyright © 2005 ScienceAsia.