Influence of nitric oxide donor on the physiological quality of seeds of Myrcia retorta Cambess

Resumo

Brazil, with its vast biodiversity, is home to several species of the Myrtaceae family with significant ornamental potential that is still underutilized. Myrcia retorta Cambess is a endemic Brazilian plant wich stands out as a promising species for ornamental cultivation. The objective of this study was to evaluate the effect of the nitric oxide donor S-nitrosoglutathione (GSNO) on the germination of M. retorta seeds, with the aim of optimizing germination conditions for the domestication of this species. The seeds were divided into two batches based on their morphology: Batch 1 (spherical seeds) and Batch 2 (flattened seeds). The seeds were treated with five concentrations of GSNO (0, 2.5, 5, 10, and 15 mM) and the parameters evaluated included germination percentage, shoot and root length, and time to stabilization of germination. In batch 1, doses of 2.5 mM and 5 mM GSNO resulted in faster germination stabilization (6 and 7 days, respectively) compared to the control (9 days). In addition, these doses increased germination percentage by 15% and 12%, respectively. However, higher concentrations (10 mM and 15 mM) were found to be phytotoxic, reducing shoot length by 30% and 45% and root length by 28% and 42%, respectively. In batch 2, although no statistically significant differences were observed, a trend towards reduced germination and growth with increasing GSNO doses was observed. It is concluded that GSNO positively affects the germination and initial development of M. retorta at low concentrations, especially in spherical seeds, suggesting its potential in the domestication process of the species for ornamental purposes. However, doses higher than 5 mM should be avoided due to toxicity risks, highlighting the need to optimize concentrations for practical application.