Effects of ascorbate foliar application on morphological traits, relative water content and extract yield of Purslane (Portulaca oleracea L.) under salinity stress

Ascorbate is a strong antioxidant which has remarkable biological effects on plants growth، including an improvement in plants'' tolerance under salinity stress conditions. In the present study، the effect of salinity stress and its interaction with ascorbic acid was investigated on some morphological traits، cell membrane stability، leaf relative water content، and extract yield of purslane (Portulaca oleracea L.) under greenhouse conditions. This research was down as factorial based on completely randomized design with 4 replications. The plants were treated in different concentrations of sodium chloride (0، 70، 140، and 210 mM) and ascorbic acid (0، 10، and 20 mM) for 4 weeks after germination. In the treated plants with salt، increases in sodium chloride concentration reduced growth parameters such as roots and shoots fresh and dry weights، roots and shoots lengths، extract yield and relative water content (RWC). However، cell membrane stability and extract percent increased. Under the same salt stress conditions، increase in ascorbic acid concentrations improved all the studied characters، so that spraying 20 mM ascorbate conducted to the maximum amount of extract percentage (0. 0054 %) and extract yield reduced (0. 037 g/plant). The study also revealed that purslane is a medicinal plant with a high resistance to salinity stress and can generally be cultivated in saline soils.