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.

DROIT ET DÉMOCRATIE CHEZ HANS KELSEN. LA CRITIQUE KELSÉNIENNE DE LA PERSONNALISATION DE L’ÉTAT

Cette étude analyse comment Kelsen, pour libérer le droit et la démocratie des traces de ce qu'il appelle les hypostases collectives ou la mythologie de l'âme collective, prend position face aux grandes théories de la sociologie et de la psychologie sociale de son temps (Durkheim, Simmel, Weber et Freud). D'abord, il s'agira de montrer comment Kelsen critique les métaphores de l'âme collective ; ensuite, de montrer comment la pensée kelsénienne sur le droit et la démocratie essaie d'échapper aux problèmes liés à la métaphore de l'âme collective. Cela peut laisser entrevoir quelques points communs entre la théorie de Kelsen et les théories contemporaines sur le droit et la démocratie libérées des prémisses de l'idée d'une communauté homogène.