Integridade do RNA e sensibilidade à dessecação em sementes: Pinus ponderosa e Coffea arabica

Abstract

Seed conservation is a fundamental strategy for maintaining genetic resources of agricultural and forest interest, and it is influenced by the physiological behavior of species in relation to desiccation and storage. In this context, this study aimed to expand the understanding of aspects related to the maintenance of seed viability in species with different storage behaviors, by combining physiological, biochemical, and molecular approaches in two species of economic and ecological relevance: Coffea arabica L. and Pinus ponderosa. In C. arabica, a species with seeds of intermediate behavior, the study investigated the reduction of desiccation sensitivity through seed incubation in regulatory substances (abscisic acid, paclobutrazol, and glycerol), followed by drying to 10 and 5% moisture content. Incubation with 15% glycerol showed the greatest potential to reduce desiccation sensitivity, maintaining 82% germination even after drying to 5% moisture content, in association with higher activity of the antioxidant enzyme ascorbate peroxidase (APX). In P. ponderosa, a species with orthodox seeds, the study investigated the RNA integrity of seeds stored at −20 °C for different periods (from 2 to 51 years) and under different germination categories (high and low) as a potential tool for monitoring physiological quality. The stored seeds maintained high viability and physiological performance for more than four decades, whereas RNA integrity remained high in all seed lots and did not prove to be a robust predictor of germination. By bringing together species with contrasting storage behaviors, the present study proposes an integrated analysis to improve the understanding of processes related to seed conservation.