Physiological changes for drought resistance in different species of Phyllanthus.

The Phyllanthus genus is widely distributed in tropical and subtropical areas of the world and present several pharmacological applications. Drought is a restrictive factor for crop development and production, and is becoming a severe problem in many regions of the world. The species Phyllanthus amarus and Phyllanthus niruri were subjected to drought stress for varying periods of time (0, 3, 5, 7, and 10 days), and afterwards, leaves were collected and evaluated for physiological and biochemical responses, such as oxidative stress markers and drought-associated defense mechanisms. Results show that P. amarus has an endogenously higher level of variables of the oxidative/antioxidant metabolism, and P. niruri presents the most significant changes in those variables when compared to control and stressed plants. For both Phyllanthus species, drought stress induces higher levels of organic acids such as malic, succinic, and citric acids, and amino acids such as proline, GABA, alanine, and valine. Moreover, P. niruri plants respond with greater glucose and corilagin contents. Therefore, considering the evaluated metabolic changes, P. amarus is better adapted to drought-stress, while P. niruri presents an acclimation strategy that increases the corilagin levels induced by short-term drought stress.