Modulation of structural carbohydrates, phenol compounds and lignin content in Eucalyptus urophylla cuttings grown under boron, copper and zinc induced-deficiency

Micronutrients participate in various plant metabolic pathways, including the synthesis of carbohydrates, lignin, and phenols, which are necessary for plant growth and defense against pests and pathogens. In this study, we evaluated the effects of nutrient solutions deplete in B, Cu, or Zn on the nutrition, growth, and production of biochemical compounds in Eucalyptus urophylla cuttings. The experiment was carried out in a greenhouse for 90 days, with clonal cuttings of E. urophylla at four months of age. The treatments evaluated were complete fertilization (CF) and individual omissions of B, Cu, and Zn in the nutrient solution. The omission of Cu and Zn increased the concentration of carbohydrates in the leaves by 10% and reduced the rate of CO2 assimilation (A) by more than 30%. Cu omission decreased the lignification process compared to complete fertilization. Flavonoid production in plants with complete fertilization was 45–75% higher than that in plants maintained under B, Cu, or Zn deficiencies. Collectively, these results suggest that micronutrient deficiencies may reduce plant productivity as well as plant resistance to pests and pathogens.