Seed reserve translocation and early seedling growth of eight tree species in a tropical deciduous forest in Mexico

Soriano, Diana; Huante, Pilar; Gamboa-de Buen, Alicia; Orozco Segovia, Alma

Seed reserve translocation and early seedling growth of eight tree species in a tropical deciduous forest in Mexico

2013

Soriano, Diana | Huante, Pilar | Gamboa-de Buen, Alicia | Orozco Segovia, Alma

Seed reserves play an essential role during germination and seedling establishment and are particularly important for species that grow in seasonal ecosystems with a short growing season. In this study, we examined (a) how and when the seedlings change their dependence from seed resources to external resources, (b) the lipid, nitrogen, and non-structural carbohydrate reserve translocation from seeds to seedlings over time, and (c) whether reserve translocation may be correlated to cotyledon and leaf lifespan of seedlings for eight tree species in a tropical deciduous forest in north-western Mexico. Our results showed that the cotyledon lifespan was not related to the cotyledon type (photosynthetic or reserve) and that the cotyledon biomass did not decrease significantly until germination. In six of the eight studied species, biomass allocation to the leaves was favored; lipids were the first reserve exhausted before the first leaves were totally expanded in seven of the eight study species. Species with the highest N concentration had expanded leaves and lost their cotyledons faster than species with a low N concentration. Our results suggest that tropical deciduous forest species employ different strategies to survive the dry season and re-sprout in the next growing season mediated by seed reserve concentrations, translocation patterns and subsequent biomass allocation.

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