Red macroalgae extracts affect in vitro growth and bud formation in Comanthera mucugensis (Giul.) L. R. Parra & Giul., an endemic dry flower species from the Chapada Diamantina (Brazil)

摘要

Comanthera mucugensis (Eriocaulaceae), also known as "sempre-viva de Mucug<^>e", is endemic to the Chapada Diamantina, Brazil. It is greatly sought after for ornamental purposes and is currently endangered due to over collection, fire and cattle raising activities. Efforts are currently being made to produce seedlings and promote the ex situ conservation of C. mucugensis through plant tissue culture. The present study evaluated the effects of red macroalgae extracts as biostimulant supplements in the culture media. The germination and cultivation of C. mucugensis plants in half-strength Murashige & Skoog (MS1/2) supplemented with different concentrations of extracts derived from Argardhiella subulata (0, 1, 2, 3 and 4 mg/mL) for 370 days were investigated. To induce bud formation, microplants were transferred to three different types of media: MS1/2, MS1/2 + 1 mg/mL of a Hpynea pseudomusciformis extract, and MS1/2 + 1 mg/mL Gracilaria sp. extract. The in vitro growth of C. mucugensis in high concentrations of A. subulata extracts diminished seed germination, seedling survival, and plant growth, although it promoted bud formation. The Gracilaria sp. extract doubled bud production in microplants, while H. pseudomusciformis extracts positively affected the growth of the aerial part and roots of the buds. The effects of these three macroalgae as plant biostimulants in the culture media can be considered an alternate method for the in vitro propagation and cultivation of C. mucugensis. This study represents the first demonstration of the effects of red algae as biostimulants in vitro C. mucugensis. (c) 2020 SAAB. Published by Elsevier B.V. All rights reserved.