Exogenous proline and glycinebetaine suppress apoplastic flow to reduce Na(+) uptake in rice seedlings.
The application of exogenous proline and glycinebetaine (betaine) confers salt tolerance on plants under salt stress. The effects of exogenous proline and betaine on apoplastic flow in rice plants under saline conditions were investigated using trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS), an apoplastic tracer. Rice plants took up more PTS under light conditions than under dark conditions. Salt stress increased PTS uptake and Na(+) content of rice leaves, but did not affect K(+) content, resulting in a lower K(+)/Na(+) ratio. Addition of proline or betaine to the saline medium suppressed Na(+)-induced PTS uptake and Na(+) accumulation, while the K(+) content was slightly increased, which led to a high K(+)/Na(+) ratio under saline conditions. These results suggest that exogenous proline and betaine suppressed Na(+)-enhanced apoplastic flow to reduce Na(+) uptake in rice plants.
Sobahan
Muhammad Abdus
MA
Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
Arias
Carlos Raul
CR
Okuma
Eiji
E
Shimoishi
Yasuaki
Y
Nakamura
Yoshimasa
Y
Hirai
Yoshihiko
Y
Mori
Izumi C
IC
Murata
Yoshiyuki
Y
D017209:Apoptosis / Q000187:drug effects*; D001622:Betaine / Q000494:pharmacology*; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D011392:Proline / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism*; D013312:Stress, Physiological
D001622:Betaine; D011392:Proline; D012964:Sodium