Investigation on Some Morphological and Physiological Characteristics of Gerbera jamesonii as Affected by Humic Acid and Nano-Calcium Chelate in Hydroponic Culture Conditions

In order to investigate the effect of humic acid (HA) and nano-calcium chelate on the cut flowers of gerbera cv. Dune, an experiment was performed as a completely randomized design with two factors and three replications in hydroponic conditions. The first factor included humic acid at 4 concentrations of 0 (control), 500, 1000, and 2000 mg L^-1 as drench and the second factor was assigned to nano-calcium chelate at 4 concentrations of 0 (control), 1, 2 and 3 g L^-1 as foliar application. The recorded growth traits included the flower and flowering stem diameter of gerbera cv. Dune, leaf and flowering stem length, and leaf fresh and dry weight. The biochemical traits were anthocyanins, carotenoids, total soluble sugars, and phenolic compounds. The results showed that leaf length and fresh and dry weight were influenced by HA so that with the increase in HA concentration, an increase was observed in leaf length and dry weight. The highest flowering stem diameter was observed in the plants exposed to 2000 mg L^-1 HA and 0 g L^-1 nano calcium chelate. Flower and flowering stem diameter were increased at higher HA rates. Total soluble sugars and phenolic compounds were affected by the application of HA. Overall, the concurrent application of HA and nano calcium chelate improved the growth and biochemical traits of Gerbera, and approximately 2000 mg/l humic acid and 2 g/l nano-calcium chelate were the most effective.