Effect of Seaweed Extract, Humic Acid and Chemical Fertilizers on Morphological, Physiological and Biochemical Characteristics of Trigonella foenum-graecum L.

Modern agriculture is searching for new biotechnologies that would allow for a reduction in the use of chemical inputs without negatively affecting crop yield or farmers' income. Seaweed extract and humic acid are used as nutrient supplements, biostimulants, or biofertilizers in agriculture and horticulture to increase plant growth and yield. To investigate the effects of SeaWeed Extract (SWE), humic acid, and chemical fertilizers on the growth, physiological and biochemical characteristics of Trigonella foenum-graecum L., a greenhouse experiment was conducted in 2016. Results showed that foliar applications of seaweed extract enhanced growth parameters. Among the different treatments, the plants that received SWE showed maximum shoot lengths, fresh and dry weights, number of pods per plant, chlorophyll “a”, chlorophyll “b”, total chlorophyll, and carotenoids. Also, application of SWE increased the amount of total phenolic and flavonoid contents in fenugreek. All fertilizer treatments increased significantly 2,2-DiPhenyl-1-PicrylHhydrazyl (DPPH) radical scavenging activity of the plants in comparison to the control. Plants treated with SWE showed stronger activity against α-glucosidase with IC50 value of 171.37 μg mL-1 in comparison with acarbose (IC50= 19.7 μg mL-1) as the reference α-glucosidase inhibitor. The data generated by this study revealed that SWE could be used as foliar spray to maximize the quality and quantity of fenugreek.