Abstract

The Byrsonima genus covers various fruit species known in the Brazilian Amazon as murucizeiro, which is considered as a species with good nutritional quality and features in its composition a variety of volatile compounds. The adaptation of plants to water stress is a complex physiological and biochemical phenomenon. Depending on the intensity and duration of stress, changes ranges from a rapid change in the flow of ions to improve the osmotic pressure, reduction of gas exchange, stabilization of cell structures by osmotic protection to a more drastic change in plant growth pattern. The aim of this work was to study gas exchange and carbon metabolism in young plants of muruci (Byrsonima crassifólia L.) submitted for water suspension. The experimental design was completely randomized with two water conditions: control and drought, with 14 repetitions, totaling 28 experimental units. The parameters analyzed were relative water content, transpiration, stomatal conductance, photosynthetic pigments, concentrations of starch, total soluble carbohydrates and sucrose. The suspension of irrigation for 25 days provided significant differences in all parameters, promoting decreases in the metabolic pathways of plants and reducing the relative water content by 26.92%, transpiration 90%, stomatal conductance 94.79%, photosynthetic pigments (Clrofila (42.1%), Chlorophyll b (50%), Carotenoids (45.1%) and overall (33.3%)) and starch in leaves and roots (73.43 and 63.63%), but increase in the control plants with the total soluble carbohydrates at 63, 87 and 39.5% and sucrose content as 64.73 and 43.99% in the leaves and roots. Therefore, these changes indicated that these plants are susceptible to soils with low water availability.

Key words: Carbohydrates, drought, muruci, photosynthetic pigments, transpiration, sucrose.