INFLUENCE OF SEED MASS IN BIOMASS ALLOCATION OF A PALM VULNERABLE OF EXTINCTION

Vigor analysis

Abstract

Seedling vigor, defined here as total seedling biomass, is directly related to seedling performance in the face of environmental harshness. Additionally, differential portioning between shoot and root biomass can be a determinant of seedling survival under conditions of resource scarcity. We aimed to determine the biomass allocation pattern of Euterpe edulis seedlings and test the hypothesis that heavier seeds produce more vigorous seedlings. We followed a germination protocol that produced 50 seedlings, 32 of which were used to calculate the total seedling biomass investment, relative growth rate (RGR), specific leaf area (SLA), and root/shoot ratio (R/S). A linear regression showed that the root/shoot ratio (R/S) increased with increasing seed mass (p = 0.03). This result may be a consequence of differing seed reserves accumulated by seeds of different masses. Seed mass was also directly related to seedling vigor (p = 0.03). Despite the lack of relationship between seed mass and RGR (p = 0.553), the positive relationship between seed mass and SLA (p = 0.03) suggests that heavier seeds have a slow-growth strategy, whereas lighter seeds have a fast-growth strategy. As heavier seeds produce more vigorous seedlings, they should be preferred when planning restoration plantations since their seedlings have greater chances of survival under harsh conditions and may present more satisfactory performance. Additionally, since the population studied is already located at the upper thermal limit of the species, we suggest that future studies focus on how seedlings of different sizes perform at different temperatures.