DOES THE FILM FORMED BY THE BORDEAUX MIXTURE ON THE LEAF SURFACE OF FIG TREES AFFECT PHOTOCHEMICAL PROCESSES?

Abstract

The objective of this work was to evaluate if the layer formed by the Bordeaux mixture on the leaf surface alters the characteristics of gas exchange, as well as the Fluorescence of chlorophyll A, when applied to combat rust. The experimental design used was entirely randomized with 2 treatments (with and without Bordeaux mixture) with leaves in 3 distinct parts of the plant branch (apical, median and basal), with 5 evaluations in 4 repetitions. The gas exchange evaluations were related to: carbon variation between the external environment and the analysis chamber, leaf temperature, transpiration rate, stomatal conductance and net photosynthesis rate. The chlorophyll A fluorescence evaluations were: maximum quantum yield of the photosystem, effective quantum yield of the photosystem, electron transport rate and photochemical and non-photochemical dissipation. In addition to the leaf area. The film formed by the Bordeaux mixture application did not interfere in the photochemical stages of photosynthesis and the fluorescence of chlorophyll A. The internal CO2 concentration, and net CO2 assimilation are gas exchange variables influenced by the position of the leaf on the branch over time. The leaves in the middle part of the branch showed the largest area, to the detriment of the apical and basal parts of the branch.