Monoculture and Coculture of Sesuvium portulacastrum and Sulla carnosa Under Saline and Non-Saline Conditions: Plant Vigour and Soil Phytodesalination

The aim of the present work was to study the possibility of coculture of the two halophytes Sesuvium portulacastrum-Sulla carnosa under saline and non-saline conditions with a special focus on plant vigour and phytodesalination potential. Plants were grown for 2 months in unperforated pots filled with agricultural soil added or not with 1.5 g NaCl. kg(-1). Thereafter, shoots were harvested for growth, water status, and mineral composition. Soil samples were also analysed. Plant productivities and phytodesalination potentials were estimated based on shoot dry weights and sodium contents as well as soil soluble sodium contents. As grown for only 2 months in monoculture, S. carnosa could not desalinate the slightly saline soil, unlike S. portulacastrum, which extracted a quarter of the added sodium quantity. Nevertheless, such a noticeable phytodesalination capacity of S. portulacastrum did not reduce soil salinity and soluble sodium content. S. carnosa growth and productivity were enhanced by both salinity and coculture under non-saline conditions, which can be explained respectively by S. carnosa halophytic behaviour and probably a positive allelopathy exerted by S. portulacastrum. By contrast, a negative allelopathy seems exerted by S. carnosa under both saline and non-saline conditions. Under moderately saline conditions, both halophytes should be grown in monoculture. The stimulatory effect of S. portulacastrum on S. carnosa under non-saline conditions needs further investigations.