| مستخلص: |
AbstractCopper (Cu) is a micronutrient involved in the formation of several metalloproteins, which play critical roles in plant metabolism. Due to its natural presence in soils, fertilization with copper and other micronutrients is commonly neglected. Proper Cu nutrition is crucial for the yield of economically significant crops, as coconut. Thus, the objective of this study was to determine the ideal dose of Cu applied via foliar fertilization and evaluate its effects on nutritional status, growth attributes, gas exchange and chlorophyll a fluorescence in Brazilian green dwarf coconut seedlings. An experiment was conducted in a greenhouse in the state of Pará, Brazil. The experimental design was randomized blocks, and the treatments consisted of Cu doses (0, 4, 8, 12, 16 and 20 g plant−1), with five replicates. Cu fertilization had a positive influence on the evaluated attributes. In the nutritional status, the lowest Cu doses resulted in higher contents of nitrogen and phosphorus. Regarding growth, fertilization with Cu at lower doses promoted increments in leaf area, height, shoot dry mass and total dry mass. Regarding gas exchange, the lowest Cu doses promoted improvements in photosynthesis rate, transpiration, and stomatal conductance. In addition, Cu at lower contents improved the efficiency of photosystem II. Thus, the recommended dose of Cu for each plant is 5 g, which is considered the ideal dose to improve the growth and functioning of the photosynthetic system in green dwarf coconut seedlings, as higher doses negatively affected the metabolic and physiological processes of the plants evaluated. [ABSTRACT FROM AUTHOR] |