Plant growth, yield and bioactive compounds of two culinary herbs as affected by substrate type

Abstract

This study reports on the influence of growing substrates on plant yield, quality, and valuable bioactive compounds of two aromatic leafy vegetables; dill and parsley, grown in net house. The treatments comprised seven substrates; basis substrate (Stender, Germany soil); peat moss; sandy soil; Germany soil + peat moss (1:1 v/v); Germany soil + sandy soil (1:1 v/v); peat moss + sandy soil (1:1 v/v) and Germany soil + peat mass + sandy soil (1:1:1 v/v). Yield traits (stem length and diameter, number of leaves and leaf area), quality (shoot and root fresh and dry weights), as well as spectrophotometric analysis of bioactive components, including chlorophyll content, phenolics and flavonoids, and antioxidant activity based on radical scavenging activity assays DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [(2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)], and ferric reducing antioxidant power (FRAP) were measured. The higher yield and quality were observed in dill and parsley grown in Germany soil, followed by that grown in Germany soil + peat, which showed better performance such as greater plant height, number of leaves and leaf areas, thicker stem diameter, and higher shoot and root fresh and dry weights when compared with other substrates. The highest content of chlorophyll, phenolics, flavonoids, DPPH and ABTS radical scavenging activity, and FRAP was found in dill and parsley plants grown in Germany soil. Dill showed higher antioxidant capacity than parsley owing to the lower content of phenolics and flavonoids compounds in parsley.