Acetyl salicylic acid induces stress tolerance in tomato plants grown at a low night-time temperature

Abstract

SummaryAbiotic stresses are becoming more prevalent as the intensity of agriculture and the demand for farmable land increase. Night-time temperature is one of the major environmental factors that influence plant metabolic processes. The permeability of cell membranes, levels of osmoregulatory substances, reproductive flowering stage, growth rate, and total anti-oxidant capacities of leaves were investigated in tomato (Solanum lycopersicum, formerly Lycopersicon esculentum Mill. ‘Liaoyuanduoli’) plants exposed to a low night-time temperature (LNT) of 9ºC or to an ambient night-time temperature (ANT) of 15ºC, with or without exogenous foliar spray treatment with acetyl salicylic acid (acetyl-SA). Three applications of 1.0 ml of 0.4 mM acetyl-SA made to 4-week-old tomato seedlings at 5 d intervals reduced the decline in fruit yield in the first and second fruit clusters due to LNT treatment by decreasing malondialdehyde (MDA) and increasing proline concentrations and total anti-oxidant capacity in tomato leaves. Under LNT stress, lipid peroxidation, measured in terms of MDA content, and hence membrane permeability were reduced by 0.4 mM acetyl-SA treatment. Superoxide dismutase (SOD) and peroxidase (POX) activities were increased by 0.4 mM acetyl-SA treatment. The accumulation of superoxide free radicals (O2•–) was inhibited, but H2O2 concentrations were increased by 0.4 mM acetyl-SA treatment. These results suggest that acetyl-SA could be used as a growth regulator to improve fruit yields and the tolerance of tomato plants exposed to LNT stress.