Foliar Application of Bee Honey or Ginger Extract Enhanced Salvia officinalis L. Growth and Productivity by Improving Phytohormones, Antioxidants, Chlorophylls, and Nutrients

Abstract

Improving the productivity of medicinal and aromatic species via eco-friendly approaches is imperative worldwide because of their therapeutic impacts. Biostimulants have been recognized among the best cultural practices in the last few decades. Among them, bee honey (BH) and ginger extract (GE) are new sources of multifunctional biostimulants that positively influence plant growth and development. However, there are currently no detailed reports on the impacts of BH or GE as promising growth and yield enhancers for medicinal and aromatic species. Also, the mechanism involved in stimulating growth and essential oil content with BH or GE is still unidentified. This work was, therefore, undertaken to analyze the impact of BH and GE on the growth, productivity, and essential oil content of sage plants (Salvia officinalis L.). Sage plants were sprayed monthly for three months with the same volume of BH (0, 5, 10, and 15 g L−1), GE (0, 5, 10, and 15 mg L−1), or tap water, which was used as a control. BH or GE application improved the plant height, branch number, herb yield, total chlorophyll content, total phenolics, and antioxidant capacity relative to the controls, more so with GE. Intriguingly, the essential oil percentage, oil yield, and oil constituents were enhanced by BH and GE. In this respect, the highest levels of biostimulants, particularly GE, were more effective. On a percentage basis, the essential oil yield per hectare was largely increased by 127.91 and 138.89% with GE (10 g L−1) in both seasons relative to the controls. The contents of IAA, GA3, and CK in THE sage leaves were substantially increased by BH and GE, and higher levels of both biostimulants and GE were more effective. The nutrient levels of N, P, K, Fe, Zn, and Mg were also elevated by BH and GE compared with the untreated plants. These results suggest that BH or GE application could be a promising biostimulant for improving the productivity of sage and provide a new understanding of their mechanisms in this aspect.