Exogenous abscisic acid inhibits the water-loss of postharvest romaine lettuce during storage by inducing stomatal closure

Abstract

Postharvest lettuce often lose water, thus affecting both its market value and consumer acceptance. However, the mechanism of the water-loss is still waiting well exploration. The aim of the present study was to investigate the effect of a foliar application of ABA on the fresh weight-loss and the chlorophyll content of postharvest lettuce as well as its association with the regulation of stomata. The present data demonstrated that exogenously application of ABA, in a concentration range of 0 to 100 µM, significantly lowered the fresh weight-loss of postharvest lettuce. ABA also delayed chlorophyll reduction during ambient storage, but this protective effect was ABA concentration-dependent. Among the tested ABA concentrations, 50 µM or lower ABA produced an inhibition effect on chlorophyll degradation in postharvest lettuce leaves. The results demonstrated that the exogenous ABA treatment can obviously reduce the transpiration rate of lettuce leaves by promoting the stomatal closure of postharvest lettuce, therefore eventually delay fresh weight-loss. The present study primarily showed that the application of exogenous ABA, which originated from a naturally-produced phytohormone, has a great potential in retaining the freshness of postharvest lettuce that is stored in an ambient condition, although possible practical application still need to be further evaluated.Keywords: lettuce; postharvest; abscisic acid; water-loss; stomatal closure. Practical Application:The effect of a foliar application of ABA on postharvest lettuce was investigated. The results demonstrated that the ABA, which originated from a naturally-produced phytohormone, can obviously reduce the transpiration rate of lettuce leaves by promoting the stomatal closure of postharvest lettuce, therefore eventually delay fresh weight-loss and chlorophyll reduction during ambient storage. The strategy could potentially be used as an alternative for lettuce producer and retailer to effectively retain the fresh of postharvest lettuce products.

Efficacy of ABA-Mimicking Ligands in Controlling Water Loss and Maintaining Antioxidative Capacity of Spinacia oleracea

“…27 It was reported that exogenous ABA application can maintain a higher chlorophyll content, lower fresh weight loss, and reduce the transpiration rate by promoting stomatal closure in postharvest lettuce. 5 However, there are still some unsolved problems for ABA application, such as chemical instability, high expenses for production, and rapid catabolism by plant enzymes. 12 AM1 and AMF4 are structurally modified ABA- mimicking ligands capable of activating multiple ABA receptors and showing effects on preventing water loss from leaves and, thus, are promising for improving drought tolerance in agricultural crops.…”

“…Moreover, it plays a vital role in reducing water transpiration by promoting stomatal closure . It was reported that exogenous ABA application can maintain a higher chlorophyll content, lower fresh weight loss, and reduce the transpiration rate by promoting stomatal closure in postharvest lettuce . However, there are still some unsolved problems for ABA application, such as chemical instability, high expenses for production, and rapid catabolism by plant enzymes .…”

“…10 It was demonstrated that exogenous abscisic acid (ABA) inhibited water loss of postharvest romaine lettuce during storage. 5 Besides, ABA has been used for keeping the freshness of postharvest flowers. 11 Nevertheless, ABA has few applications in practices due to its chemical instability, high production expenses, and rapid catabolism by plant enzymes.…”

“…Transpiration is the principal reason for water loss in fruit and vegetables, , and the rates of water loss are affected by their shapes and structures, as well as environmental factors . Therefore, appropriate handling and distribution practices in combination with optimal conditions are crucial for preserving quality and reducing postharvest losses .…”

“…Low storage temperatures, high relative humidity, and low O 2 atmosphere can reduce water loss of tissues and extend postharvest life of fresh produces. ,, However, these measures are not necessarily practicable, since some fresh produces of tropical and subtropical origin (e.g., mango, tomato, and cucumber) are chill-sensitive and may develop symptoms of chilling injuries at temperatures below thresholds . It was demonstrated that exogenous abscisic acid (ABA) inhibited water loss of postharvest romaine lettuce during storage . Besides, ABA has been used for keeping the freshness of postharvest flowers .…”