Pre-sowing enrichment of Echinacea angustifolia seeds with macronutrients improved germination performance and early seedling growth via stimulating the metabolism of reserves

Abstract

Seed enrichment with macronutrients such as N, K and P through nutrient seed-priming is a low-cost and low-risk technique to improve seed vigor and proper establishment of early seedlings. The objective of this study was to assess the potential of nutrient-enrichment of Echinacea angustifolia seeds, a high-valuable medicinal plant in pharmaceutical industry, with NK, KP or NKP through seed-priming with KNO3, KH2PO4 and a mixture of KNO3 and KH2PO4, respectively, on seed germination indices and early growth of seedlings, relative to non-enrichment treatments (non- and water-priming). The data showed that vigor of NK-, KP- or NKP-enriched seeds improved when compared with non-enriched seeds, while the highest seed vigor was manifested by NKP-enriched seeds. This finding was supported by higher final germination percentage, germination rate indices, coefficient uniformity of germination and seedling vigor index, and less mean germination time observed for macronutrient-enriched seeds, especially for NKP-enriched seeds. Other evidence to support enhanced vigor of macronutrient-enriched seeds was increased activity of total dehydrogenase (an indicator for accessing seed viability and vigor) in NK-, KP- and NKP-enriched seeds, with the highest activity in NKP-enriched seeds. In addition, the growth of early seedlings obtained from NK-, KP- and NKP-enriched seeds increased relative to that of the seedlings obtained from non-enriched seeds, with the highest early growth for the seedlings originating from NKP-enriched seeds. The activities of α-amylase and β-amylase were stimulated in NK-, KP- and NKP-enriched seeds, with the highest stimulation being observed in NKP-enriched seeds. This finding was consistent with the highest total reducing sugars and total soluble sugars in NKP-enriched seeds. Therefore, pre-sowing enrichment of the seeds with NKP can be suggested to improve seed vigor and vigorous establishment of early seedlings in nutrient-poor soils.