RESUMO
The effects of root abscisic acid (ABA) signal on Na+ transport and photosystem 2 (PS2) in Jerusalem artichoke (Helianthus tuberosus) under salt stress (150 mmol·L-1 NaCl) were examined by applying ABA synthesis inhibitor sodium tungstate to roots. Sodium tungstate inhibited ABA synthesis in roots, reduced root Na+ efflux, and increased the efficiency of Na+ transport from roots to leaves under salt stress. Salt stress increased leaf Na+ content and did not affect leaf membrane lipid peroxidation, PS2 reaction center protein and PS2 maximum photochemical efficiency (Fv/Fm ). The inhibition on root ABA synthesis significantly increased leaf Na+ accumulation, aggravated leaf membrane lipid peroxidation, impaired PS2 reaction center protein, decreased Fv/Fm, and induced PS2 photoinhibition. In conclusion, root ABA signal was beneficial to reducing leaf Na+ accumulation and preventing PS2 oxidative damage by inducing root Na+ efflux and inhibiting Na+ transport to the aerial part in H. tuberosus under salt stress.
