Cryopreservation of excised embryonic axes of <i>Nothapodytes nimmoniana</i> (Graham) Mebberly—A vulnerable medicinal tree species of the Western Ghats

Abstract

Desiccation sensitivity and freezing tolerance of excised embryonic axes from the seeds of <i>Nothapodytes nimmoniana</i> (Graham) Mebberly and their cryopreservation were examined. Zygotic embryos with cotyledons excised from fully ripened fruits possessed 55.7% moisture content (MC) and 86.67% of them germinated in Murashige and Skoog (MS) medium devoid of plant growth regulators (PGR). Dehydration under laminar airflow for 120 min reduced the MC of the embryos to 19.6% and germination to 68%. Subsequent reduction in MC to 15.4, 14.2 and 12.1% also reduced the germination. Embryos dehydrated for 120 min after 1-wk-storage in Liquid nitrogen (LN) showed 60% germination, which was the optimum condition obtained in the study. The LN treated embryos developed into healthy seedlings after 30-60 d of inoculation in MS basal medium similar to desiccated control. Prolonged desiccation damaged the plumule where only root formation was observed. The study reveals the possibility of long term <i>ex situ</i> conservation of <i>N. nimmoniana</i>, which produces large and intermediate type of seeds, through zygotic embryo cryopreservation.