Water stress and salinity tolerance of Mesembryanthemum crystallinum L. in hydroponics

Abstract

In their natural growing environment, halophytes such as ice plants are subjected to salt and drought stresses simultaneously, but our understanding of the impacts of combined stress on plants is restricted. This study evaluated the individual and combined impacts of salinity and drought stress on plant development, mineral content, proximate content, and phytochemical composition of Mesembryanthemum crystallinum. Treatments consisted of four different irrigation treatments of 1 = 100 mL once a day; 2 = 100 mL once every 2 days; 3 = 100 mL once every 4 days; 4 = 100 mL once every 8 days in conjunction with four different salt concentrations of (0, 200, 400 and 800 ppm) applied in each treatment. Salt concentrations were determined by gradually raising the concentration of NaCl in the nutrient solution, while the control treatment received daily irrigation without NaCl. The results showed that plants irrigated with 800 ppm salinity every four days had a substantial rise in leaf number, fresh and dry weight. During the growing weeks, the chlorophyll content was similar among treatments, except for week eight, when the combination of salinity and drought reduced the chlorophyll content among treatments. The highest yields of N, Mg, and Cu were consistently recorded in plants that were not subjected to saline treatment, whereas P, K, Ca, Na, Zn, and Fe were consistently documented in plants that were subjected to both drought and salinity. Plants subjected to drought stress alone had high levels of acid detergent fibre (ADF), crude fat, protein, and neutral detergent fibre (NDF), whereas plants subjected to a combination of drought and salinity had the greatest levels of ash and moisture. The same pattern was seen in phytochemical accumulation, with polyphenols and flavonols being abundant in plants only exposed to drought stress. Plants irrigated every eight days, on the other hand, consistently had the greatest antioxidant capacity (FRAP) regardless of drought or saline treatment. These results imply that M. crystallinum could provide an additional source of nutrients in areas prone to salinity and drought. As a result, domestication in South Africa, a country with a scarcity of water, is highly suggested.