EMBRYO CAP REMOVAL AND HIGH-TEMPERATURE EXPOSURE STIMULATE RAPID GERMINATION OF NEEDLE PALM SEEDS

High synchrony, rate, and germination of needle palm [Rhapidophyllum h ystrix (Pursh) H.A. Wendle & Drude] seeds were achieved only after rem oving the sclerotesta and embryo cap, which imposed physical dormancy. After scarification, recently harvested seeds or seeds stored for 12 months at 5C and 100% relative humidity had 96% and 98% final germinat ion (G), with 9 to 11 days required to achieve 50% of final germinatio n (T50) at 30C. Germination temperature controlled G, T50, and days be tween 10% and 90% of final germination (T90-T10) of scarified seeds, w ith respective values of 98%, 9 days, and 5 days at 30C, and 18%, 31 d ays, and 12 days at 15C. Seeds with 36% moisture at harvest had no red uction in G until moisture was <14%. Germination of seeds with t9% moi sture declined from 80% if stored at 0C to 33% if stored at -10C; no s eeds germinated after storage at less than -10C.