Differences in water relations, leaf ion accumulation and excretion rates between cultivated and wild species of Limonium sp. grown in conditions of saline stress

Plants of two genotypes, Limonium pectinatum (wild species) and the hybrid Limonium latifolium x Limonium caspium cv. Beltlaard grown in greenhouse co nditions were irrigated with a 200 mM NaCl solution for 4 months (saline tr eatment). The dry weight of cv. Beltlaard plants was significantly reduced by salinity but remained unchanged in Limonium pectinatum. At the end of th e experiment none of the parameters related to floral stems (number, height and dry weight) in Limonium pectinatum was affected to any significant deg ree by salts, while the treated plants of the Beltlaard genotype showed sig nificant reductions in these parameters compared with the control plants. L eaf water relations under saline conditions showed a similar behaviour in b oth genotypes, achieving the same degree of leaf osmotic adjustment through the accumulation of Na+ and Cl-. Although the highest levels of these ions were found in treated plants of Limonium pectinatum, the lower accumulatio n of salts in the tissues of cv. Beltlaard plants generated major toxicity and nutritional disturbances, which negatively affected growth. The Na+ and Cl- excretion rate through salt glands was higher in Limonium pectinatum t han in cv. Beltlaard, which indicated that the wild species was more effici ent decreasing the toxic salt content of its tissues. The ultrastructure of these salt glands is depicted and described.