SEMINIFEROUS PROPAGATION OF Cordia oncocalyx (Allemão) Baill. AND BIOMETRIC CHARACTERIZATION OF DIASPORES AND SEEDS

Jayane Karine Pereira De Araújo,Mauro Vasconcelos Pacheco,Diógenes Fernandes Dos Santos,Poliana Coqueiro Dias Araujo,Jessica Sabrina Ovídio De Araújo

doi:10.1590/1983-21252022v35n116rc

Abstract

ABSTRACT Cordia oncocalyx Allemão Baill., widely known as “pau-branco”, is a native species from the Caatinga (Brazilian Savannah) and has socioeconomic and environmental potential; however, there are few silvicultural studies on this species. Therefore, this paper aimed to analyze and compare the biometric characteristics of diaspores and seeds through manual biometrics and by digital image processing, and to evaluate the in vitro and ex vitro germination of C. oncocalyx. In the biometrics evaluation, three hundred diaspores and three hundred seeds were used, applying manual and digital biometrics. Subsequently, ex vitro emergence was determined, testing mechanical scarification (in different regions of the diaspore) and chemical scarification (immersion in sulfuric acid for 90 min and 180 min). Finally, in vitro germination was tested with different compositions of Murashige & Skoog (M&S) culture medium and sucrose addition. Results showed that digital image processing is a viable and fast technique to obtain the biometric parameters of C. oncocalyx fruit and seeds. Chemical and mechanical treatments on diaspores have not influenced seed emergence (0.33%). The composition of the culture medium has influenced the germination percentage, and the maximum value of 96% % was obtained with 6 g/L of sucrose and 0.90 g/L of M&S medium. Thus, the seminiferous propagation of C. oncocalyx can be performed successfully when the seeds are germinated in vitro, and the digital image processing shows the solidity and applicability aiming to evaluate the quantitative parameters of seed and fruit of this species.

Highlights

Cordia oncocalyx (Allemão) Baill., widely known as “pau-branco”, is an endemic species of the Boraginaceae family in the Caatinga region (Brazilian Savannah)
The epicarp is plain, glossy, and its color varies from light brown to dark brown, with a stony endocarp. They are surrounded by an increasing chalice in light brown color, which facilitates its spreading by the wind
The description of the external characteristics of diaspores and seeds of C. oncocalyx is in agreement with what was described by Carvalho

Summary

Introduction

Cordia oncocalyx (Allemão) Baill., widely known as “pau-branco”, is an endemic species of the Boraginaceae family in the Caatinga region (Brazilian Savannah). The gradual increase in the extraction of its wood and non-wood products and the lack of recommendations regarding the proper propagation methodology have resulted in reduction of C. oncocalyx individuals in the species' natural populations, considered a rare species with the possibility of being extinct in the future (MAIA, 2012). C. oncocalyx propagation is sexual; there are limiting factors for the production of seedlings of the species, such as fruit morphology. The scarcity of silvicultural studies makes it difficult to overcome these problems, since this information is not included in the Instructions for Analysis of Forest Species Seeds. Knowledge about fruit biometrics and the adequacy of an efficient propagation protocol are essential for conservation and perpetuation of the species

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Conclusion