Trithrinax acanthocoma Drude: morphobiometry, morphoanatomy, and viability by tetrazolium test in a rare Brazilian palm

Abstract

Trithrinax acanthocoma Drude is an endangered palm tree, rarely found and restricted to southern Brazil. The scarcity of basic information on the biology and quality of its seeds hinders the development of strategies for physiological evaluation, seedling production, and species conservation. Given this gap, this study aimed to characterize the morphobiometry of fruits and pyrenes, establish correlations between biometric variables, describe the morphoanatomy of the embryo, and, based on structural knowledge, propose a methodology for the tetrazolium test. Fruits from matrices located in the municipality of Curitibanos, Santa Catarina (Brazil), were evaluated for morphological characteristics, dimensions, mass, and water content, while the embryos underwent anatomical analysis. The tetrazolium test was conducted in a 2 × 2 with two concentrations (0.1% and 0.2%) and two batches of pyrenes for six hours at 25 °C. Biometric data were analyzed using descriptive statistics and Spearman’s correlation, and viability results were analyzed using analysis of variance and Tukey’s test. The fruits were subglobose in shape and had a high pulp content, while the pyrenes ranged from globose to ovoid, with ruminated endosperm and a small, lateral, and poorly differentiated embryo. The 0.1% tetrazolium solution yielded more uniform staining and a higher viability estimate (89%) than the 0.2% solution. The established protocol proved to be fast, reliable, and applicable, providing new information and practical tools for programs to conserve, manage, and propagate the species.

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