Viability in the storage of seeds of Lecythis spp. and functional characterization, chemical composition, and structural resistance during the germination process of Lecythis lanceolata Poir
Name: VITÓRIA FERREIRA GOMES
Publication date: 27/02/2026
Examining board:
Name |
Role |
|---|---|
| CRISTIANE COELHO DE MOURA | Examinador Interno |
| LIANA HILDA GOLIN MENGARDA | Examinador Externo |
| LUCIANO BESTETE OLIVEIRA | Examinador Externo |
| RODRIGO SOBREIRA ALEXANDRE | Presidente |
Summary: Considered one of the largest tropical forests in the Americas, the Mata Atlântica is currently highly fragmented, making the adoption of conservation strategies for native species increasingly urgent. In this context, Lecythis pisonis and Lecythis lanceolata (Lecythidaceae) stand out as native species with food, ornamental, ecological, and bioeconomic potential, yet remain poorly studied, particularly regarding propagation, seed physiology, and conservation. These species present difficulties in vegetative propagation, making seeds the primary source of propagation. However, their seeds exhibit hard seed coats, irregular germination, and possible physical and physiological dormancy, reinforcing the need to understand the physiological and biochemical processes involved in germination and early seedling development. Reserve mobilization—mainly lipids, carbohydrates, and proteins—is a key process for seedling establishment, directly influencing morphophysiological quality. In the first chapter, seeds and seedlings of Lecythis lanceolata were classified into ten ontogenetic stages, allowing an integrated evaluation of germination, emergence, dormancy, and early growth in relation to reserve mobilization dynamics. Biochemical and structural analyses were performed, including quantification of tannins, lignin, and structural carbohydrates, as well as techniques such as X-ray diffraction, nuclear magnetic resonance, and thermogravimetric analysis. The results indicated that glucose and xylose were the only carbohydrates detected in the seed coat, and that lipids constitute the main reserve of the species, being preferentially mobilized during germination, in addition to evidencing initial investment in structural and defensive compounds. In the second chapter, the effect of ultralow temperature storage (-86 ºC and -196 ºC), with or without post-storage thermal conditioning, was evaluated on the physiological quality of seeds of Lecythis pisonis and Lecythis lanceolata. Parameters of emergence, vigor, and early seedling growth were analyzed, along with ecophysiological attributes such as chlorophyll index and chlorophyll fluorescence, aiming to assess potential damage to the photosynthetic apparatus and metabolic integrity. The results revealed contrasting responses between species. Lecythis pisonis showed sensitivity to storage at -196 ºC, indicating limitations for cryopreservation in liquid nitrogen, likely associated with structural and metabolic damage caused by intracellular ice formation. However, the species maintained viability and vigor when stored at -86 ºC, provided that embryo moisture content was not below 7%, highlighting the importance of water content in freezing tolerance. In contrast, Lecythis lanceolata showed no sensitivity to the tested temperatures, demonstrating greater physiological stability under thermal stress. Additionally, post-storage thermal conditioning did not significantly influence germination, emergence, or early development in either species, suggesting that this procedure is not decisive for physiological recovery after exposure to ultralow temperatures. Overall, the results indicate that the success of ultralow temperature storage depends on seed water content and species-specific physiological characteristics, reinforcing its potential as a conservation strategy when properly adjusted. These approaches contribute to the development of efficient ex situ conservation methods, production of high-quality seedlings, and strengthening of productive chains, supporting the preservation and sustainable use of these native species.
Key words: Sapucaias. Seed Propagation. Cryopreservation. X-Ray Diffraction. Nuclear Magnetic Resonance. Monosaccharides.
