| مستخلص: |
• Shoot dry matter yield of C. longifolia plants was significantly increased by Mn, Cu, Zn and Mo supplementation under field conditions. • The highest increase in shoot biomass was at the 1.5 mM level of each applied micronutrient. • Supplying Mn, Zn, Cu and Mo to C. longifolia markedly increased the concentrations and amounts of P, K, Ca, Mg, Cu, Zn, Mn and B in shoots relative to the zero controls. • Shoot concentrations of N and Fe were significantly reduced with increasing supply of Mn, Cu, Zn and Mo to C. longifolia plants. • There was evidence of mineral-to-mineral antagonism, as well as mineral-to-mineral synergy in the rhizosphere. Cyclopia longifoli a Vogel L. is endemic to the Cape fynbos, and cultivated for the production of Honeybush tea, a herbal beverage with health benefits and economic potential in the cosmetic and nutraceutical industries. In this study, field plants were supplemented with different levels of Cu, Mo, Mn and Zn using 0, 0.5, 1.0 and 1.5 mM solutions of Na 2 MoO 4 ·2H 2 O and MnSO 4 ·2H 2 O and 0, 1.0 and 1.5 mM solutions of ZnSO 4 ·7H 2 O and CuSO 4 ·5H 2 O in a split-application. Plant shoots were harvested at 300 days after fertilization for biomass determination and analysis of mineral nutrients. The results showed significantly increased shoot dry matter yield of C. longifolia in response to Mn, Cu, Zn and Mo supplementation under field conditions, and was highest at the 1.5 mM level of each applied micronutrient. These results suggest that field fertilization of Cyclopia plants can lead to increased plant growth and greater tea yield, in addition to overcoming nutrient mining from the annual harvests of plant shoots for making tea. Furthermore, supplying Mn, Zn, Cu and Mo to C. longifolia also significantly increased the concentrations and amounts of P, K, Ca, Mg, Cu, Zn, Mn and B in shoots relative to the zero controls, suggesting an increase in tea quality with trace element supplementation. However, the shoot concentrations of N and Fe were markedly reduced with increasing supply of Mn, Cu, Zn and Mo to C. longifolia plants, an indication of mineral-to-mineral antagonism in the plant rhizosphere. [ABSTRACT FROM AUTHOR] |
