Evaluation of the Effect of Fulvic Acid and Humic Acid on Some Morphological and Phytochemical Traits in Different Harvest Stages of Aloe barbadensis Leaf

Barbadensis is one of the 250 species of the genus Aloe, which is widely used in the pharmaceutical, cosmetic and food industries. The aim of this study was to investigate the effect of different concentrations of humic acid and fulvic acid on morphophytochemical traits of barbadensis species at different harvest stages. This study was performed as a factorial experiment based on completely randomized design with three replications. Treatments include fulvic acid (0, 200 and 400 mg.l-1), humic acid (0, 50 and 100 mg.l-1) and different stages of harvest (30, 40 and 50 days). Measured traits included leaf length and diameter, gel percentage, fresh weight and dry weight, leaf bark percentage, total soluble solids, total phenol, total flavonoids, antioxidant activity and vitamin C. The results of analysis of variance showed that the treatments had a significant effect on the measured traits at the level of 1 and 5%. Based on the results of means comparison, the highest antioxidant activity (63.2%) was recorded in the treatment of 200 mg.l-1 fulvic acid in the third harvest (fiftieth day). Also, the highest amount of vitamin C (3.6 mg per 100 ml) was observed in the treatment of 50 and 100 mg.l-1 of humic acid in the first and second harvest (thirty and fortieth day). The results showed that fulvic acid had a positive effect on total phenol, total flavonoid and antioxidant activity. humic acid also had a positive and significant effect on plant yield and increased leaf size and leaf gel content.