Cleome gynandra L. (C4 plant) shows higher tolerance of salt stress than its C3 close relative, C. viscosa L

The effect of salt stress on some physiological and anatomical parameters in two species ofCleome, C. gynandra (C4 plant) and C. viscosa (C3 plant) was investigated. Seedlings were grown inpotted soil in greenhouse for 3 months, before being subjected to salinity stress. Salinity was inducedby adding sodium chloride solution at the concentration of 75 mM for 15 days. Growth andphysiological parameters were recorded every three days after addition of NaCl. The results showedthat salinity caused slightly higher reduction in plant height of C. gynandra than C. viscosa. A smallreduction in chlorophyll content was observed in C. viscosa after 15 days of NaCl treatment. Prolinecontent in roots, stems and leaves of both species was generally unaffected by NaCl treatment. Theamount of hydrogen peroxide, malondialdehyde and electrolyte leakage increased in response to NaCl.These parameters, which indicate secondary oxidative stress response, were more affected in C.viscosa than C. gynandra. Significant reductions in leaf thickness, petiole and root diameters, and rootvascular cylinder were observed in NaCl-treated plants of C. viscosa compared to control plants. Theresults suggested that C. gynandra was more tolerant of salt stress compared to C. viscosa.