Análise dos efeitos da microgravidade simulada por ação de um clinostato 2D em plantas de Salvia hispanica por quatro horas por meio de uma abordagem histológica e bioquímica.

Abstract

Since the beginning of human civilizations, plants have been used for therapeutic purposes. Furthermore, it is known that gravity can be one of the factors influencing the development and production of phytotherapeutic compounds (or secondary metabolites). With the growing interest in space exploration, simulated microgravity has been employed to study and understand the morphophysiological and biochemical changes of these organisms in such environments. Based on this, the present study aimed to investigate the effects of simulated microgravity using a 2D clinostat on plants of the species Salvia hispanica, known as chia, in order to assess morphological, histological, and biochemical changes. The exposure to the equipment lasted four hours, with rotations at 35 and 50 rpm, in addition to the control group (CN), which was not subjected to the 2D clinostat. Morphological data were collected over four weeks following the stress exposure, and at the end of this period, material was collected for histological evaluation, and aqueous extracts of the leaves from each group were obtained. Among the morphological aspects analyzed, it was observed that, compared to the control (CN), plants in the 35 rpm group did not exhibit significant alterations. However, the 50 rpm group showed a ~24% reduction in internode distance (ID) in the first week, a ~26% and ~37.5% decrease in stem diameter (SD) in the first and second weeks, respectively, and a ~20% reduction in leaf diameter (LD) in the third week. Regarding histological analyses, the structure of the xylem, phloem, and central cavity tissues was altered at both tested rotation speeds. As for the biochemical profile, the content of phenolic compounds and flavonoids—secondary metabolites with potential therapeutic activity—was quantified. Phenolic compounds decreased by ~18.5% at 35 rpm and increased by ~90% at 50 rpm. For flavonoids, a slight, non-significant decrease of ~10% was observed at 35 rpm, along with a non-significant increase of ~14.5% at 50 rpm. These results provide insights into the behaviour of Salvia hispanica under simulated microgravity conditions, as well as its pharmacological and biotechnological potential.