Tomato and eggplant scions influence the effect of rootstock under Na2SO4 salinity

摘要

A short-term experiment was conducted to investigate whether the effect of rootstock on plant response to salinity depends on the solanaceous species used as scion. Tomato cv. 'Ikram' and eggplant cv. 'Black Bell' were grafted onto two tomato interspecific hybrids ('Beaufort' and 'He-Man'). Plants were grown in an open soilless cultivation system and supplied with two nutrient solutions: non-saline control and a saline solution (adding 15 mM Na2SO4, 3.7 dS m(-1)). Plant dry biomass production and partitioning were influenced by salinity, but its effect was depending on the rootstock/scion combination. 'Beaufort' eliminated the deleterious effect of salinity when tomato was used as scion, but reduced (-29.6%) the shoot biomass of eggplant. 'He-Man' had a different effect on scion growth under saline conditions: shoot biomass was less reduced in eggplant (-20.6%) than in tomato (-26.8%). Under salt stress, 'Beaufort' reduced the accumulation of Na+ in tomato leaves more than in eggplant, whereas no differences were observed between tomato and eggplant grafted onto 'He-Man'. Stem Na+ accumulation followed a different pattern. The increase of Na+ in the stems was similar for tomato and eggplant grafted onto 'Beaufort', whereas stems of tomato accumulated more Na+ compared to eggplant grafted onto 'He-Man'. The opposite response of the tested rootstocks to salt stress when the scion was either tomato or eggplant seems to be partially related to the capacity of the rootstock and scion to exclude Na+ from the shoot. However, the results of nutrient accumulation within plant tissues imply that other mechanisms in addition to ion competition are involved in the salt resistance of grafted plants.