Germination of Dipteryx alata Vogel: does temperature modulate early seed physiological performance?

Abstract

Abstract Temperature is one of the main environmental factors regulating seed germination and early seedling development, playing a fundamental role in seed technology, seedling production, and ecological restoration. This study aimed to evaluate the effect of temperature on the germination of Dipteryx alata Vogel seeds in order to understand the possible germinative physiological responses of the species. Seeds were collected from a 38-year-old experimental plantation located in the Pederneiras State Forest, São Paulo, Brazil. Seed physiological quality was assessed through germination tests conducted in a BOD-type chamber under six constant temperatures: 15, 20, 25, 30, 35, and 40 °C. The evaluated parameters included germination percentage, mean germination time (MGT), mean emergence time (MET), germination speed index (GSI), emergence speed index (ESI) and fresh weight of normal seedlings. The results showed that temperatures of 30 °C and 35 °C provided the best physiological performance, characterized by high germination percentage, formation of vigorous seedlings, high GSI values, and greater biomass accumulation. In contrast, seeds subjected to 15 °C and 20 °C showed delayed germination, lower GSI, and reduced formation of normal seedlings, whereas no germination occurred at 40 °C, where seed deterioration associated with fungal and bacterial contamination was observed. Our results indicate high physiological aptitude and plasticity of the species, and demonstrate that knowledge of the germination thermal niche of D. alata is essential for the conservation and sustainable use of this species in the Cerrado, as well as for providing a basis for future studies focused on its adaptive potential under scenarios of environmental change.