Does regenerative strategy vary between populations? A test using a narrowly distributed Atlantic Rainforest palm species

Abstract

Germination rate and seed mass are important factors determining the proportion of seedlings that become established in a habitat, especially where resources are limited and under adverse environmental conditions. Variation in seed attributes can determine a species’ potential to adapt to new climates. This study aimed to investigate the germination behavior of Lytocaryum weddellianum along climatic gradients at two altitudes in the Serra dos Orgaos, Rio de Janeiro, Brazil. We conducted ex situ experiments on germination under two light conditions (light or dark) and three levels of water potential (Ψ = 0, −0.4 or −0.8 MPa) over 8 months. In addition, seeds of different sizes were sown and after 6 months seedlings were divided into shoot and root components. The following growth parameters were measured: root, shoot and total biomass, leaf area, specific leaf area and leaf area ratio. Our results showed that the high- and low-altitude populations had different germination rates, seed mass, and resource allocation in seedlings. The lower altitude population, with higher temperatures and humidity, higher germination rates, produced heavier seeds, and their seedlings invested more in root and total biomass. Meanwhile, seedlings from the higher altitude site, with less available light, had a greater investment in foliar parameters. These differences in the two populations’ seedling establishment strategies over an altitudinal gradient in the Serra dos Orgaos suggest that the species may have the potential to adapt to predicted climate change in this region.