Hydrogen peroxide pretreatment induces osmotic stress tolerance by influencing osmolyte and abscisic acid levels in maize leaves

摘要

Hydrogen peroxide (H 2 O 2 ) functions as a signal molecule in plants under abiotic and biotic stresses. Leaves of detached maize ( Zea mays L.) seedlings were used to study the function of H 2 O 2 pretreatment in osmotic stress resistance. Low H 2 O 2 concentration (10 mM) which did not cause a visual symptom of water deficit (leaf rolling) was applied to the seedlings. Exogenous H 2 O 2 alone increased leaf water potential, endogenous H 2 O 2 content, abscisic acid (ABA) concentration, and metabolite levels including soluble sugars, proline, and polyamines while it decreased lipid peroxidation and stomatal conductance. Osmotic stress induced by polyethylene glycol (PEG 6000) decreased leaf water potential and stomatal conductance but enhanced lipid peroxidation, endogenous H 2 O 2 content, the metabolite levels, and ABA content. H 2 O 2 pretreatment also induced the metabolite accumulation and improved water status, stomatal conductance, lipid peroxidation, ABA, and H 2 O 2 levels under osmotic stress. These results indicated that H 2 O 2 pretreatment may alleviate water loss and induce osmotic stress resistance by increasing the levels of soluble sugars, proline, and polyamines thus ABA and H 2 O 2 production slightly decrease in maize seedlings under osmotic stress.