Leaf gas exchange, water relations, nutrient content and growth in citrus and olive seedlings under salinity
2008
Melgar, J.C.,Universidad de Cordoba (Spain). Departmento de Agronomia | Syvertsen, J.P.,University of Florida, Lake Alfred (USA). Citrus Research and Education Center | Martinez, V.,Centro de Edafologia y Biologia Aplicada del Segura, Espinardo (Spain) | Garcia-Sanchez, F.,Centro de Edafologia y Biologia Aplicada del Segura, Espinardo (Spain)
The effects of salinity on growth, leaf nutrient content, water relations, gas exchange and chlorophyll fluorescence were studied in six-month-old seedlings of citrus (Citrus limonia) and rooted cuttings of olive (Olea europaea cv. Arbequina). Citrus and olives were grown in a greenhouse and watered with half strength Hoagland's solution plus 0 or 50 mM NaCl for citrus, or plus 0 or 100 mM NaCl for olive. Salinity increased Cl- and Na+ concentrations in leaves and roots in both species and reduced total plant dry mass, net photosynthetic rate and stomatal conductance. Decreased growth and gas exchange was apparently due to a toxic effect of Cl- and/or Na+ and not due to osmotic stress since both species were able to osmotically adjust to maintain pressure potential higher than in non-salinized leaves. Internal CO2 concentration in the mesophyll was not reduced in either species. Salinity decreased leaf chlorophyll a concentration only in citrus.
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