Chilling Tolerance of Wheat Seedlings Is Related to an Enhanced Alternative Respiratory Pathway

Abstract

Pretreatment with exogenous hydrogen peroxide (H 2 O 2 ) mitigated the water loss of wheat leaves exposed to 4°C for 24 h. The same treatment also partially reduced the increases of electrolyte leakage and H 2 O 2 production of the chilled plants. These observations suggest that H 2 O 2 pretreatment could effectively induce chilling tolerance. The capacity of the alternative respiratory pathway and the expression of the gene encoding the alternative oxidase ( AOX1 ) were substantially elevated by H 2 O 2 treatment under either normal or chilling conditions. Salicylhydroxamic acid (SHAM, an inhibitor of the alternative respiratory pathway) decreased the tolerance of plants to chilling conditions and reversed the chilling tolerance induced by exogenous application of H 2 O 2. These observations indicate that the tolerance of plants to chilling might be related to an enhanced alternative respiratory pathway.