The influences of exogenous H2O2 and salicylic acid (SA) treatments on the alternative respiratory pathway (ARP) in aged potato (Solanum tuberosum L.) tuber slices were compared. The results showed that both H2O2(5.0 mmol/L) and SA (0.1 mmol/L) treatments had a significant inducing effect on ARP capacity (Valt) and its ratio to total respiration (Valt/Vt) in potato slices aged for 24 h. With a monoclonal antibody against the alternative oxidase (AOX), Western blotting results showed that both H2O2 and SA treatments increased the AOX expression levels in aged potato tuber slices. However, the results of oxygen isotope discrimination experiments showed that H2O2 had no influence on the in vivo ARP activity (ρValt) and its contribution to Vt(expressed as ρValt/Vt) in potato slices aged for 24 h, but SA had a significant influence on the ρValt and ρValt/Vt values of the aged potato tuber slices. These results indicate that there are differences between the effects of H2O2 and SA on ARP in plant tissues. Both of them possess the ability to induce ARP capacity through inducing AOX expression. However, SA can simultaneously stimulate the operation of ARP, but H2O2 can not.
H2O2
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