Dormancy, storability, and germination of seeds inMagnolia punduana(Magnoliaceae)

Abstract

Magnolia punduana Hk. f. & Th. (syn. Michelia punduana) is a threatened tree species restricted to northeastern India. The seeds remain dormant for 6 months after dispersal. Seed development and breaking of dormancy was investigated in the present study. Physical treatments such as water (cold, hot, and boiling) and acid and manual scarification proved ineffective in breaking dormancy. Matured seeds had linear and underdeveloped embryos at the time of dispersal with an embryo to seed length (E:S) ratio of 0.13. Germinating seeds showed a significant increase in the embryo length with an E:S ratio of 0.36. Cold stratification (CS) at 5 °C effectively broke dormancy. The embryo grew significantly after CS, indicating the presence of “non-deep simple” morphophysiological dormancy (MPD). Application of GA3had a significant effect on germination and the lowest germination time with the shortest T50was observed in seeds treated with 3000 mg·L−1GA3. KNO3did not have an influence on breaking dormancy except in combination with GA3, which increased the germination percentage significantly. CS for 90 days and GA3(3000 mg·L−1) at 25 °C resulted in optimum germination. In the test for viability, seeds stored at 5 °C showed highest viability of 66.66% after 180 days.