investigation of the effect of chitosan and salinity stress on physiological traits and some chemical compounds in purslane (portulaca oleracea l.)

Portulaca oleracea l. is a medicinal plant of the portulacaceae family, known for its protective effects against liver damage, viral hepatitis, diabetes, and cancer. the main purpose of this study was to evaluate the effects of salinity stress and chitosan on the growth and physiological traits of the portulaca oleracea l. salinity stress is one of the most important factors limiting plant growth and development, especially in arid and semi-arid regions. chitosan is a biological elicitor and a major component of the cell wall of many fungal species. this study was conducted by a completely randomized factorial design. for this purpose, the plant was exposed to different concentrations of nacl (0, 25 and 35 ds/m) and chitosan (0, 0.2 and 0.4 g/l), and subsequently harvested and assayed for shoot length, root length, relative water content, photosynthetic pigments, soluble sugar, proline, k+, na+, and fatty acids. the results of two-way analysis of variance showed that different concentrations of salt, chitosan and their interaction significantly affected most of the said parameters. the 25 ds/m salinity caused a favorable growth; while 35 ds/m salinity retarded plant growth. increasing salinity monotonically decreased the shoot length and rwc and increased na+ and carotenoids; however, the root length, proline, chl a, k+, and soluble sugars showed a hormetic response. a 0.4 g/l chitosan acted as an improving agent under the stress conditions, mainly due to positive changes in the physiological traits. also, this treatment significantly increased the major fatty acids, linolenic acid (omega-3) and linoleic acid (omega-6). with growing soil salinity, using appropriate dose of chitosan can alleviate the adverse effects of salinity on portulaca oleracea l. portulaca oleracea l. is a medicinal plant of the portulacaceae family, known for its protective effects against liver damage, viral hepatitis, diabetes, and cancer. the main purpose of this study was to evaluate the effects of salinity stress and chitosan on the growth and physiological traits of the portulaca oleracea l. salinity stress is one of the most important factors limiting plant growth and development, especially in arid and semi-arid regions. chitosan is a biological elicitor and a major component of the cell wall of many fungal species. this study was conducted by a completely randomized factorial design. for this purpose, the plant was exposed to different concentrations of nacl (0, 25 and 35 ds/m) and chitosan (0, 0.2 and 0.4 g/l), and subsequently harvested and assayed for shoot length, root length, relative water content, photosynthetic pigments, soluble sugar, proline, k+, na+, and fatty acids. the results of two-way analysis of variance showed that different concentrations of salt, chitosan and their interaction significantly affected most of the said parameters. the 25 ds/m salinity caused a favorable growth; while 35 ds/m salinity retarded plant growth. increasing salinity monotonically decreased the shoot length and rwc and increased na+ and carotenoids; however, the root length, proline, chl a, k+, and soluble sugars showed a hormetic response. a 0.4 g/l chitosan acted as an improving agent under the stress conditions, mainly due to positive changes in the physiological traits. also, this treatment significantly increased the major fatty acids, linolenic acid (omega-3) and linoleic acid (omega-6). with growing soil salinity, using appropriate dose of chitosan can alleviate the adverse effects of salinity on portulaca oleracea l.