Algal extract and proline promote physiological changes in mango trees during shoot maturation

Abstract

Water stress should be adequately managed during shoot maturation to improve the floral induction of mango grown in semi-arid regions. In this scenario, proline association with algal extracts has a potential stress-mitigating effect. However, even though this practice has been reported separately for some crops, its effects on mango are still unknown. From this perspective, this study investigated the role of proline and algal extract in mitigation of water deficit effects during shoot maturation of the mango variety ‘Tommy Atkins’ grown in the tropical semi-arid region. The study consisted of five consecutive individual experiments (five foliar application treatments) in a randomized block design and a 4 x 2 factorial corresponding to i) four proline concentrations (Pro): 0.0% (without proline), 0.287, 0.575, and 1.150%, and ii) the presence of algal extract (AE) (presence and absence). The following parameters were evaluated: photosynthetic pigments, soluble carbohydrates, photochemical and non-photochemical efficiency, and flowering and production uniformity. Carotenoids were interactively affected by the factors evaluated. On the other hand, as additive effects, proline provided the highest values of gas exchange and total soluble carbohydrates, with a higher internal CO2 concentration and greater flowering uniformity. The application of proline and the algal extract of A. nodosum promoted different responses in mango physiology and can be used during shoot maturation.

Physiology and production of sugar-apple under water stress and application of proline

“…Probably, a longer period without the supply of water to sugar-apple plants caused the formation of ROS such as hydrogen peroxide (H 2 O 2 ) and singlet oxygen ( 1 O 2 ), which are usually produced in greater quantity when plants are under stress conditions. These ROS cause destabilization of the cell membrane, ionic imbalance and damage to the cytoplasm, releasing ions; thus, the higher the leaked content of the cell, the greater the damage to the cell membrane (Cunha et al, 2022). Fernandes et al (2021), in a study evaluating cell damage in sugar-apple through the combination of two levels of electrical conductivity of irrigation water (1.3 and 4.0 dS m -1 ) and five doses of potassium (K1 -50%, K2 -75%, K3 -100%, K4 -125% and K5 -150%), found that the increase in potassium doses caused a linear increase in the %EL of sugar-apple leaves, equal to 5.64% per 25% increment in K 2 O doses.…”