Ion uptake by halophytic plants to mitigate saline stress in Solanum lycopersicon L., and different effect of soil and water salinity

Soil and water salinization are affecting an increasing number of countries in the world, especially in arid and semi-arid regions, and cause sensible reductions of agricultural land extension and of crop yields. Consociation with halophytic plants is a promising but not yet widely investigated strategy of salt stress reduction in crops. In this experiment, tomato plants were cultivated in saline conditions, alone and in consociation with three different halophytic species (Portulaca oleracea L.; Salsola soda L.; Atriplex hortensis L.). The salinity was brought either by the soil or by the irrigation water. Consociation with P. oleracea gave the best results in terms of increase of tomato growth and yields, while S. soda caused excessive nutritional competition against tomato due to its fast growth, undoing the positive effects of saline ions uptake. A. hortensis gave intermediate results. Salinity of water resulted in causing more severe stress on the plants, and consequently highlighted more the benefical effect of salt uptake performed by the halophytes on the main crop; salinity of soil on the contrary appeared to be less decisive, probably due to the leaching effect of the irrigation water.