Effect of humic acid on morph-physiological traits, nutrients uptake and postharvest vase life of pot marigold cut flower (Calendula officinalis cv. Crysantha) in hydroponic system

Humic acid (HA) with pseudo-hormonal activity has an important effect on nutrients uptake، yield and quality of crop products. Therefore، this experiment was conducted in soilless condition to evaluate the best HA concentration (0، 250، 500، 750 and 1000 MG/l) of nutrition solution and its effects on morphological traits، nutrients uptake، and postharvest vase life of pot marigold. Based on the results، HA showed significant effects on physio-morphological traits of pot marigold. Accordingly، as compared with control plants، the leaf area and chlorophyll content (a، b and total) as plant photosynthetic capacity، flower number and total phenol concentration were significantly affected by HA application. Also، as compared with control plants (without HA application)، HA showed a significant effect on P and Ca uptake. Flower longevity، as an important postharvest quality index، was increased 20% higher than control plants، in 250 mg/L concentration of HA. The results of the current investigation revealed that application of HA with 250 and 500 mg/L concentrations in soilless culture of pot marigold ‘cv. Crysantha’ could be recommended.