Seed germination of six mature neotropical rain forest species in responseto dehydration

We studied effects of dehydration and rehydration on germination of seeds o f six mature tropical rain forest species-Cupania glabra Swartz, Cymbopetal um baillonii Fries, Poulsenia armata (Miq.) Standl., Stemmadenia donnell-sm ithii (Rose) Woodson, Rheedia edulis Triana & Planch. and an understory pal m Chamaedorea alternans H. Wendl. -from Veracruz, Mexico. Before the seeds were sown, their water content was reduced by 0 (control), 30, 54 and 72% o f their original water content. Dehydration affects the ability of seeds to rehydrate, as well as the rate and final percentage of germination when se eds are subsequently rehydrated. Seed survival and germination behavior sho wed three patterns: (1) C. baillonii, P. armata and S. donnell-smithii had greater tolerance to seed dehydration than C, glabra, C. alternans and R. e dulis; (2) partial dehydration enhanced germinability of C. glabra and C. b aillonii seeds; and (3) partial dehydration of C. alternans and R. edulis s eeds resulted in delayed or sporadic germination. A relationship was found between the effects of dehydration on germination and the seasonality of se ed production.