Gas exchanges and photosynthetic pigments of 'Tommy Atkins' mango as a function of fenpropimorph/Trocas gasosas e pigmentos fotossinteticos de mangueira 'Tommy Atkins' em funcao de fenpropimorfe

HIGHLIGHTS: Fenpropimorph promotes a higher physiological activity in mango. Fenpropimorph favors carbon assimilation in mango. Fenpropimorph dose of 1.3 g per linear meter of plant canopy promotes higher transpiration and stomatal conductance in mango. The objective of the present study was to evaluate the influence of the application of fenpropimorph and paclobutrazol on gas exchanges and photosynthetic pigments of 'Tommy Atkins' mango grown in the semi-arid region in different evaluation periods. Two experiments were carried out in 'Tommy Atkins' mango orchards in the first production cycle between September and December 2018 (first experiment) and between September and December 2019 (second experiment) in Petrolina, PE, Brazil. The experimental design adopted was randomized blocks in split plots in time, 4 X 4 + 1, with four replicates. The plots corresponded to the concentrations of fenpropimorph: 0, 0.7, 1.0, and 1.3 g per linear meter of plant canopy diameter plus the additional paclobutrazol treatment (1 g per linear meter of plant canopy diameter), and the subplots corresponded to the evaluation dates (0, 30, 60, and 90 days after the first application of treatments). The following traits were evaluated: C[O.sub.2] assimilation rate, stomatal conductance, internal C[O.sub.2]. concentration, transpiration, water use efficiency, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids. The fenpropimorph dose of 1.3 g per linear meter of plant canopy promotes a higher rate of C[O.sub.2] assimilation; however, paclobutrazol was more effective in the accumulation of chlorophyll a and total chlorophyll, and the use of fenpropimorph did not interfere in the concentration of photosynthetic pigments. Key words: Mangifera indica L., growth regulator, plant physiology O objetivo do presente estudo foi avaliar a influencia da aplicacao de fenpropimorfe e paclobutrazol nas trocas gasosas e pigmentos fotossinteticos de mangueira 'Tommy Atkins' cultivada no semiarido em diferentes periodos de avaliacao. Foram realizados dois experimentos em pomares de mangueira 'Tommy Atkins' no primeiro ciclo produtivo entre setembro e dezembro de 2018 (primeiro experimento) e entre setembro e dezembro de 2019 (segundo experimento) em Petrolina, PE, Brasil. O delineamento experimental adotado foi o de blocos casualizados em parcelas subdivididas no tempo, 4 X 4 + 1, com quatro repeticoes. As parcelas corresponderam as concentracoes de fenpropimorfe: 0; 0,7; 1,0 e 1,3 g