Combined Applications of Aminoethoxyvinylglycine with Salicylic Acid or Nitric Oxide Reduce Oxidative Stress in Peach During Ripening and Cold Storage

Abstract

The effects of pre-harvest application of aminoethoxyvinylglycine (AVG) alone or in combination with nitric oxide (NO) or salicylic acid (SA) on the oxidative stress and fruit quality during ripening and cold storage were investigated in peach Prunus persica L. Batsch. cv. ‘Oz Delight’. Trees were sprayed with 830 g ha-1 AVG 10 days before anticipated harvest, or post-harvest fumigated with 10 µL L-1 NO or dipped in 2 mM aqueous solution of SA for 5 min in the following treatments (untreated control, pre-harvest AVG, post-harvest NO, post-harvest SA, pre-harvest AVG + post-harvest SA and pre-harvest AVG + post-harvest NO). Combined application of pre-harvest AVG and post-harvest SA resulted in reduced ethylene production, respiration rate, fruit weight loss, SSC and SSC:TA with higher fruit firmness, CIE L*, b* and ho values and TA during ripening and cold storage, as compared with control. There was no consistent trend in the activities of antioxidant enzymes in any treatment. The activities of SOD, CAT, and POD were reduced, whereas PPO enzymes increased with advancement in fruit ripening and cold storage periods. Fruit treated with combined application of pre-harvest AVG and post-harvest SA exhibited reduced oxidative stress with higher activities of POD and PPO enzymes, as compared with control during ripening and cold storage. Fruit fumigated with NO alone or in combination with AVG showed higher radical scavenging activity during ripening as well as storage, as compared with all other treatments. In conclusions, pre-harvest application of AVG in combination with post-harvest SA treatment exhibited synergistic effect in the reduction of ethylene production, respiration rate, fruit softening, changes in fruit quality (colour, SSC, TA and SSC:TA ratio) and consequently reduced oxidative stress during peach fruit ripening and cold storage.