Respostas fisiológicas e morfológicas de mudas de landi (Calophyllum brasiliense cambess) a diferentes doses de glyphosate

Abstract

Weeds have become undesirable in commercial forest plantation areas because they compete for water, light and nutrients with forest species causing damage, due to this they must be controlled. Generally the areas of forest planting companies are very vast, thus, the most effective method of controlling invasive plants is the chemical. Glyphosate is the herbicide most used for weed control because it is non-selective, has a systemic action, broad spectrum of action and relatively low cost. However, if it is not applied correctly the product may cause damage to non-target species. These damages will depend on the doses of glyphosate and the susceptibility of the crop. Calophyllum brasiliense Cambess is a native species of great geographic distribution, has noble wood and has been used for reforestation in flooded areas. In recent years the interest of forest companies by this species has grown. Thus, the objective was to quantify the morphological and physiological effects of doses of glyphosate on calophyllum brasililense Cambess. The experiment was carried out at the Federal University of Tocantins, Gurupi campus. The experimental design was a completely randomized (DIC) with 5 treatments (180, 360, 540 and 720 g a.i. L-1 of glyphosate Roundup Original® + control without application) and 10 replicates, each plant being a repetition. Morphological analyzes of visual toxicity (7 in 7 DAA), height and diameter (10 in 10 DAA), biomass (MSC, MSF, MSR and MST), root volume and leaf area (at the end of the experiment) and physiological analyzes (A), stomatal conductance (gs), transpiration (E), and internal carbon (Ci). The instantaneous efficiency of water use (U) and instantaneous efficiency of carboxylation ( EiC) through gas exchange data. At the lowest dose (180 g a.i. L-1) plants were recovering from the effects caused by glyphosate so that at the end of the experiment the physiological parameters were statistically matched to the control. However, the other doses (360, 540 and 720 g a.i. L-1) significantly affected both the morphology and the physiology of the species.