Hydrological regime modulates functional anatomy, imbibition dynamics, and early establishment of Copernicia alba seeds under submerged conditions

Abstract

Seed traits associated with tolerance to flooding are poorly understood in tropical palms, despite their potential importance for establishment in wetlands. This study aimed to evaluate whether composite seed lots collected from flooded and dry sites differ in functional anatomical traits, water uptake dynamics, germination, mean germination time, and normal seedling formation under submerged conditions. The composite lots were compared for seed anatomy, histochemistry, chemical composition, imbibition, greenhouse emergence, mean germination time, and post-germinative performance. Seeds from the flooded-site lot had a thicker inner epidermis, greater total seed-coat thickness, and a larger relative lipid area in the endosperm than seeds from the dry-site lot. Water uptake followed a triphasic pattern in both lots; however, the flooded-site lot showed slower initial imbibition and a longer mean germination time under water. In sawdust + sand, germination was similar between lots, whereas under water the flooded-site lot reached 86.50 % of germination and the dry-site lot 45.01 %. The contrast was even more pronounced for normal seedling formation: the flooded-site lot maintained 100 % of normal seedlings in both substrates, whereas the dry-site lot reached only 6.85 % under water.

KEYWORDS: Carandá, flood tolerance, functional seed anatomy, wetland palms.