Variation in Response of Seeds of Three Tropical Orchid Species Towards Storage Conditions for Seed Viability

Abstract

Ripe seeds collected from undehisced and almost matured capsules of three tropical Orchid species viz., Phaius tankervilliae, Rhyncostylis retusa and Aerides odoratum were first used for standardization of concentration of Tetrazolium (Tz) solution and minimum time required for its viability testing. Another part of the collected capsules/seeds were dried in ambient room temperature for one month wrapping with butter paper. Seeds scooped from such dried capsules were wrapped within a piece of butter paper separately for each species and stored in oven dried test tubes prior set with a little amount of CaCl2 (1:50:: desiccant: seed) covered with a small amount of cotton at the bottom of the test tubes. Test tubes with seeds were plugged with cotton and closed with parafilm, then stored in three different conditions viz., in fridge at 4°C, in culture room (25±2°C) and in room temperature. Stored seeds were evaluated for its viability at three intervals- 90, 180 and 270 days of storage (DOS). Viability testing using Tz solution was suitable for Orchid species under study with specific duration as: 24 hours treatment at 0.5% solution for P. tankervilliae, whereas it was only 3 and 2 hours at 0.5% solution for R. retusa and A. odoratum respectively. Out of three storage conditions, fridge storage was found to be better for two species- P. tankervilliae and R. retusa, whereas the result could not be ascertained in case of A. odoratum. Therefore, variation in potentiality of retaining seed viability under different conditions was mainly depended on the genetic architecture of individual species as well as its interaction with storage conditions.