Interpopulational seed hydration memory does not affect seed germination of Xiquexique gounellei (F.A.C.Weber ex K.Schum) Lavor & Calvente subsp. gounellei (Cactaceae) under water deficit

Abstract

SummaryThe passage of seeds through hydration and dehydration cycles (HD cycles) can be essential for the acquisition of tolerance and survival to abiotic stress conditions. Since seeds of species from semi-arid ecosystems naturally undergo discontinuous hydration when they germinate, the aim of this study was to compare the seed germination of Xiquexique gounellei subsp. gounellei (Cactaceae) from different populations growing in the Caatinga, a Tropical Dry Forest in Northeastern Brazil, submitted to water deficit after HD cycles. We collected seeds from two populations growing in the municipalities of Canindé de São Francisco and Sousa. We subjected the seeds to 0, 1, 2 and 3 HD cycles and placed them to germinate at osmotic potentials 0.0, -0.2, -0.4, -0.6, -0.8 and -1.0 MPa. From the results of this study, we observed that the two populations do not respond significantly to HD cycles, however the population of Canindé de São Francisco showed a higher germinability in a shorter period, as well as a higher germination speed. Although the two populations grow in the same ecosystem, we observed different germinative behaviour between the populations. Differences in seed germination from the two populations may be related to the phenotypic plasticity of the species influenced by genotypic variation and differences in seasonality and microhabitat conditions in which the populations are growing.