RESUMO
Hypertonic salt stress with different concentrations of NaCl increased the levels of extracellular ATP of Arabidopsis leaves. And, hypertonic salt stress decreased the levels of F v /F m (the maximal efficiency of photosystem II), Φ PSII (the photosystem II operating efficiency), qP (photochemical quenching), and intracellular ATP (iATP) production. The treatment with ß,γ-methyleneadenosine 5'-triphosphate (AMP-PCP), which can exclude extracellular ATP from its binding sites of extracellular ATP receptors, caused a further decrease in the levels of F v /F m , Φ PSII, qP, and iATP production of the salt-stressed Arabidopsis leaves, while the addition of exogenous ATP rescued the inhibitory effects of AMP-PCP on Φ PSII , qP, and iATP production under hypertonic salt stress. Under hypertonic salt stress, the values of F v /F m , Φ PSII , qP, and iATP production were lower in the dorn 1-3 mutant than in the wild-type plants. These results indicate that the responses of photosystem II and intracellular ATP production to salt stress could be affected by extracellular ATP.
Assuntos
Trifosfato de Adenosina/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Cloreto de Sódio/farmacologia , Folhas de Planta/efeitos dos fármacosRESUMO
Pore size adjustable mesoporous silica was synthesized by adsorption of varying amounts of sodium dodecyl benzenesulfonate at the surface of silica activated by zinc ion via a novel surface charge reversal route. The pore size and volume can be adjusted from 5.9 to 13.76 nm and 0.88 to 1.08 cm(3) g(-1), respectively, with increasing the SDBS concentration from 0.77 to 3.08 mmol L(-1). Adsorption of Zn(2+) as a function of pH and N(2) adsorption/desorption isotherms demonstrated that the metal ions such as Zn(2+) could be readily removed with dilute nitric acid without apparent collapse of the pore structure at the proper range of SDBS concentration.