Effects of humic acid derived from sediments on the postharvest vase life extension in cut chrysanthemum flowers

Previous research has shown that humic acid can extend the vase life of cut flowers. However, the mechanisms responsible for this effect are unclear. In this study, the physiological mechanisms of foliar humic acid fertilizer on cut chrysanthemum flower postharvest vase life were investigated. Seedlings of chrysanthemum were sprayed with the same volume of distilled H2O, inorganic NPK fertilizer and organic foliar humic acid fertilizer every 15 days (15, 30, 45, 60 days after transplanting). The results showed that foliar application of humic acid improved the chlorophyll content, the net photosynthetic rate (P-n), contents of soluble sugars and soluble protein in the leaves of chrysanthemum, and increased the flower size, fresh weight, vase life, activities of antioxidant enzymes, and decreased the malondialdehyde (MDA) content in cut chrysanthemum flowers. It was concluded that the responses of the foliar humic acid fertilizer on postharvest vase life extension of cut chrysanthemum flowers could be related with the higher chlorophyll content, Pn, contents of soluble sugars and soluble protein in the leaves, the greater flower size, fresh weight, activities of antioxidant enzymes, and the lower MDA content in cut chrysanthemum flowers. (C) 2014 Elsevier B.V. All rights reserved.