Salinity and Salt-Priming Impact on Growth, Photosynthetic Performance, and Nutritional Quality of Edible Mesembryanthemum crystallinum L.

Mesembryanthemum crystallinum L. is a nutritious edible facultative halophyte. This study aimed to investigate the physiology and quality of M. crystallinum L. grown under different salinities and salt-priming conditions. All plants were first grown in 10% artificial seawater (ASW) for 10 days. After that, some plants remained in 10% ASW while the others were transferred to 20%, 30%, 40%, or 50% ASW for another 10 days. Some plants also underwent a salt priming by transferring them gradually from 10% to 100% ASW over a span of 10 days (defined as salt primed). All plants were green and healthy. However, there were reductions in shoot and root productivity, leaf growth, and water content, but also an increase in leaf succulence after transferring plants to higher salinities. The salt-primed plants showed higher photosynthetic light use efficiency with higher chlorophyll concentration compared to other plants. The concentrations of proline, ascorbic acid (ASC), and total phenolic compounds (TPC) increased as percentages of ASW increased. The salt-primed plants switched from C(3) to crassulacean acid metabolism photosynthesis and accumulated the greatest amounts of proline, ASC, and TPC. In conclusion, higher salinities and salt priming enhance the nutritional quality of M. crystallinum L. but compromises productivity.