Osmotic priming effects on emergence of Physalis angulata and the influence of abiotic stresses on physalin content

Abstract

Physalis angulata is a medicinal plant with valuable pharmacological activities. The physiology of stress in this plant can play an important role in the induction or maximization of the production of physalin F, B, D and G, bioactive secondary metabolites described as immunosuppressive, anti-malarial and anti-leishmanial agents. P. angulata was cultivated from seeds which had been previously primed in PEG 6000 solution and non-primed seeds. After 45days, the plants were exposed to water restriction and saline stress in the field for 13days. Seedling emergence and growth after stress treatment were assessed. Seco-steroids were quantified in leaves and stems by HPLC/PDA. The emergence rate was 14% higher in primed seeds. The types of irrigation proved to have a significant influence on the number of leaves and fruits, plant height and stem diameter, irrespective of whether the seeds were primed or not. The biomass of the fruits, stems and roots was also decreased by water restriction and saline stress. Physalin content in ethanol extracts increased in leaves, mainly after saline stress and from primed seeds. Despite the biomass reduction caused by the treatments, stress application led to an increase in the production of bioactive metabolites.