Impact of water availability on Caryocar brasiliense (Caryocaraceae) seedling establishment

Abstract

In seasonal habitats, adjusting plant reproductive strategies and early developmental patterns to water availability is crucial for sustaining natural populations. Understanding these adaptive mechanisms is vital for conserving and domesticating key species. Caryocar brasiliense, an economically significant fruit tree native to the Cerrado biome, faces threats from deforestation and unsustainable extraction. This study examines how water availability affects the seedling establishment and growth of this species. Over a year, we assessed the impact of irrigation on pyrene (endocarp + seed) germination, seedling survival, morphology, and anatomy of the hypocotyl (an underground stem structure), through six evaluations. Our findings revealed that irrigation promotes seedling emergence and growth of stems, leaves, and roots, especially at the end of the rainy season. However, plants exhibited enhanced growth during the wet/warm season, even without irrigation. The hypocotyl plays a pivotal role in drought resistance: it is enduring, shows secondary growth influenced by water, and serves as a starch-storing structure. C. brasiliense seedlings and young plants display remarkable drought resistance, attributed to their deciduous nature, hypocotyl reserves, and deep root systems. Despite this inherent resilience, irrigation significantly boosts the species establishment and early growth, underscoring its importance for crop cultivation and habitat restoration.