Morphological, biochemical and nutritional variations in a Mexican purslane (Portulaca oleracea L.) variety exposed to salt stress during the vegetative stage

Abstract

Salt stress limits productivity of crop plants, and differential responses may be observed among genotypes. Herein we analyzed the effects of saline stress induced by the application of different concentrations of sodium chloride (0.00, 0.25, 0.50, 0.75, and 1.00 M NaCl) in a local Mexican variety of purslane (Portulaca oleracea L.) named ‘Atlapulco’ in vegetative stage. The NaCl concentrations were applied in the Hoagland nutrient solution used in irrigation for 14 days under greenhouse conditions, using perlite as a substrate. Analysis of variance and comparison of means were carried out with the data obtained. NaCl concentrations from 0.50 M reduced canopy coverage 36.8% and stem diameter by almost 21%, while all NaCl doses reduced the leaf area by 28.2%, on average, as compared to the control. Dry stem biomass and chlorophyll b were reduced by the saline gradient. Secondary stems and root length increased with 1.00 M by 23 and 29%, respectively. Proline concentration both in leaves and stems increased by 223.9 and 138%, respectively, when applying 1.00 M NaCl, compared to the control. Applying 0.75 and 1.00 M NaCl reduced N concentrations by 47 and 28.8% in leaf tissues, respectively, compared to the control. The concentrations of P and K in leaves, and K in roots also decreased with the saline treatments, while those of Ca and Mg were not affected in any of the analyzed tissues. The highest concentrations of Na in leaves were observed in doses 0.50 and 0.75 M NaCl, surpassing the control by 67.5 and 73.1%, respectively. The findings reported herein are very useful to propose programs for the recovery of saline soils in the region and design environmental policies aimed at mitigating the effects of climate change on food production.