Can H2O2 application reduce chilling injury of horticultural crops?
W.C. Lin, and G.S. Block
Book of Abstracts, Southeast Asia Symposium Quality and Safety of Fresh and Fresh Cut Produce Greater Mekong Subregion Conference on Postharvest Quality Management in Chains, August 3-5, 2009, Radisson Hotel, Bangkok, Thailand.
2009
บทคัดย่อ
Hydrogen peroxide (H2O2) at low endogenous concentration is a signaling compound leading to adaptation and stress tolerance during plant abiotic stress. At high concentrations, H2O2 can lead to cell death. Our study was to examine whether exogenous application of H2O2 could lead to stress tolerance and thereby improve the quality of horticultural crops. This study consisted of two types of experiments: chilling injury in sweet potato (growth chamber) and storage quality in sweet peppers (greenhouse). In sweet potato (growth chamber experiment), excised leaves had less chilling injury, when stored at 2.5°C for 2 to 3 days, if the petioles were immersed in 15 mM H2O2 as compared to de-ionized water (control). When cv. Purple (PUR) sweet potato shoots were subjected to 3-day chilling at 2.5°C, a 48h pre-treatment of 150 mM H2O2 under 16h photoperiod reduced chilling injury, but H2O2 showed no effect under 8h photoperiod. In sweet peppers (greenhouse experiment), decay index of sweet peppers after 4-week storage was lower when 500 ppm H2O2 was administered through the hydroponic system prior to fruit harvest. The beneficial effect gradually declined when H2O2 was continuously applied for a period of a few months. A similar decline in the beneficial effect on quality was observed through pulsed H2O2: postharvest decay was reduced if sweet peppers were harvested one or two weeks after H2O2 application, but no benefit was observed in those harvested after three weeks. Our data seem to support the hypothesis that endogenous H2O2 leads to stress tolerance. Our preliminary data also illustrated that the benefits of exogenous H2O2 application could not be observed under all experimental conditions. Rather, H2O2 effects were observed under specific conditions, such as photoperiod in sweet potato, or specific number of weeks between H2O2 application and harvest in pepper fruits. Therefore further studies are required to devise specific, practical H2O2 applications for assured benefits in crop production.