Water deficit is the main cause of abiotic stress to which plants are susceptible, whether cultivated or those that are underexploited, such as Physalis peruviana L. Searching for tools that contribute to the management of water deficit in plants is fundamental for the maintenance of agriculture, especially in arid and semi-arid areas around the world. Thus, the objective of this study was to evaluate the effect of chemical priming with proline and sodium nitroprusside as promoters of increased tolerance to water deficit in P. peruviana plants. Plants grown under well hydrated conditions (FC of 70±5%) were sprayed with proline (10 and 20 mM) or sodium nitroprusside (25 and 50 μM) and evaluated after exposure to water deficit (FC of 20±5%). Plants cultivated under water deficit without pretreatment showed reductions in the variables of water relations, gas exchange and growth. Proline and sodium nitroprusside were effective in maintaining less negative water potential, contributing to improvements in gas exchange, such as CO2 assimilation, stomatal conductance and transpiration. Thus, it was possible to measure greater tolerance to water deficit in pretreated plants and, consequently, greater biomass accumulation. It appeard that pretreatment of proline and sodium nitroprusside can have a priming effect against water deficit in P. peruviana plants.

Salt stress severely constrains agricultural productivity in arid and semi-arid regions. This study evaluated exogenous proline as an osmoprotector in Physalis ixocarpa Brot. (Mexican husk tomato) under salinity. Germination screening identified 75 mM NaCl as a threshold stress level, reducing germination by 38.9% while maintaining seedling viability. Proline pretreatment (30-min imbibition) at 8 mM restored germination to 78% and fresh weight to control levels under salt stress. In vitro experiments revealed that 8 mM proline enhanced chlorophyll content above salt-stressed controls while reducing root length from 9.72 to 5.08 cm, indicating resource reallocation toward photosynthetic protection. Infrared spectroscopy showed characteristic polysaccharide shifts and bands potentially associated with proline incorporation. Gas chromatography–mass spectrometry metabolomics of stem–leaf extracts revealed salt-induced synthesis of nitrogenous osmolytes (such as long-chain amines) and carbohydrate reorganization from α-D-glucopyranoside to β-D-riboside. Proline treatment restored the original carbohydrate profile while generating pyrrolidine derivatives (2.83%), evidence of active proline metabolism. Phenolic antioxidants (e.g., catechol) present in controls were absent under both salt stress and proline treatment, suggesting that proline’s protective mechanism may operate through metabolic regulation of osmolyte pathways and membrane stabilization rather than inducing phenolic antioxidant synthesis. These findings demonstrate proline’s multifaceted protective mechanisms and support its potential application for enhancing salt tolerance in this crop.