title: Physiological adjustment to salt stress in Jatropha curcas is associated with accumulation of salt ions, transport and selectivity of K+, osmotic adjustment and K+/Na+ homeostasis.
abstract: This study assessed the capacity of Jatropha curcas to physiologically adjust to salinity. Seedlings were exposed to increasing NaCl concentrations (25, 50, 75 and 100 mm) for 15 days. Treatment without NaCl was adopted as control. Shoot dry weight was strongly reduced by NaCl, reaching values of 35% to 65% with 25 to 100 mm NaCl. The shoot/root ratio was only affected with 100 mm NaCl. Relative water content (RWC) increased only with 100 mm NaCl, while electrolyte leakage (EL) was much enhanced with 50 mm NaCl. The Na(+) transport rate to the shoot was more affected with 50 and 100 mm NaCl. In parallel, Cl(-) transport rate increased with 75 and 100 mm NaCl, while K(+) transport rate fell from 50 mm to 100 mm NaCl. In roots, Na(+) and Cl(-) transport rates fell slightly only in 50 mm (to Na(+)) and 50 and 100 mm (to Cl(-)) NaCl, while K(+) transport rate fell significantly with increasing NaCl. In general, our data demonstrate that J. curcas seedlings present changes in key physiological processes that allow this species to adjust to salinity. These responses are related to accumulation of Na(+) and Cl(-) in leaves and roots, K(+)/Na(+) homeostasis, transport of K(+) and selectivity (K-Na) in roots, and accumulation of organic solutes contributing to osmotic adjustment of the species.
authors: Faculdade de Educação, Ciências e Letras do Sertão, Central, Universidade Estadual do Ceará, Quixadá, Ceará, Brazil.
authors: E N
authors: EN
authors: Silva
authors: Departamento de Bioquímica e Biologia Molecular/Instituto Nacional de Ciência e Tecnologia em Salinidade (INCTsal/CNPq), Universidade Federal do Ceará, Fortaleza, Ceará, Brazil.
authors: J A G
authors: JA
authors: Silveira
authors: Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.|Faculdade Leão Sampaio, Juazeiro do Norte, CE, Brazil.
authors: C R F
authors: CR
authors: Rodrigues
authors: Departamento de Engenharia Florestal da UFPB, Universidade Federal de Campina Grande, Patos, Paraíba, Brazil.
authors: R A
authors: RA
authors: Viégas
mesh_terms: D001692:Biological Transport; D018533:Biomass; D002712:Chlorides / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D006706:Homeostasis; D031286:Jatropha / Q000187:drug effects / Q000502:physiology*; D009997:Osmotic Pressure; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology; D018520:Plant Shoots / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D054712:Salinity; D055049:Salt Tolerance; D036226:Seedlings / Q000187:drug effects / Q000502:physiology; D012965:Sodium Chloride / Q000378:metabolism* / Q000494:pharmacology; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism
chemical_list: D002712:Chlorides; D014867:Water; D002734:Chlorophyll; D012965:Sodium Chloride; D011188:Potassium
keywords: Ion accumulation; Jatropha curcas; organic solutes; osmotic adjustment; salinity