Mango is the most exported fruit of Brazil, especially grown in São Francisco Valley (tropical semiarid) where there is high temperatures and low air humidity, a condition that can cause stress to plants. Thus, the current study aimed to evaluate the effectiveness of different sunblocks to alleviate the abiotic stress of “Palmer” mango trees grown in a semiarid environment. The experimental design consisted of randomised blocks with six treatments, four repetitions and three plants per plot. The treatments consisted of different strategies of sunblocks as follows: (T1) control (no sunblock); (T2) calcium carbonate (50 g · L ⁻¹ ); (T3) sunblock (5 mL · L ⁻¹ ); (T4) sunblock (5 mL · L ⁻¹ ) + calcium carbonate (50 g · L ⁻¹ ); (T5) sunblock (5 mL · L ⁻¹ ) + sunblock silicon concentrated (20 mL · L ⁻¹ ) and (T6) sunblock (20 mL · L ⁻¹ ). The results indicate a clear action of sunblock in attenuating the abiotic stress of mango, with a persistent effect with time elapsing, considering the evaluated interval. The sunblock clearly promotes a differentiated leaf coverage pattern, protecting the photosynthetic apparatus and increasing its performance and consequently improving the production of plant reserves. The use of calcium carbonate individually promotes a very short protective effect, without positive reflexes after a few days of application. Mango fruit yield is affected by the sunblock with an increase of 4.2 t · ha ⁻¹ from the treatment with sunblock (20 mL · L ⁻¹ ) in relation to the control treatment.

Using water with high salt concentrations in irrigated agriculture can affect sensitive plants’ metabolic and biochemical functions. Therefore, strategies are needed to minimize the adverse impacts of salt stress. This study aimed to evaluate radish plant growth, water relations, and biochemical and nutritional responses as a function of irrigation water salinity and exogenous ascorbic acid (AsA) application. The experiment was conducted in a controlled greenhouse under a completely randomized design in a 3 × 2 factorial scheme with four replicates, using one plant per experimental unit. Treatments consisted of three levels of irrigation water salinity (0.5, 3.0, and 5.0 dS m-1) and ascorbic acid application [without (0 mM) and with (1 mM)]. Increased salinity (3.0 and 5.0 dS m-1) affected growth, water status, biochemical traits, and nutrient accumulation in radish plants. Stem diameter (55.0%), shoot mass ratio (14.5%), relative growth rate (9.0%), and soluble sugars in shoot (29.8%) and root (47.6%) increased with 1 mM AsA application, especially at 5.0 dS m-1. Applying 1 mM AsA reduced Na⁺ and Cl⁻ cont 0ents in both shoot and root at all salinity levels and increased the Mg²⁺ content in shoot and root and Ca²⁺ content at 3.0 and 5.0 dS m-1.

Pitaya is a high-value tropical fruit with a postharvest life constrained by rapid physiological deterioration. This study aimed to evaluate the efficacy of chitosan-based (CH) biopolymeric coatings, enriched with ascorbic acid (AA), on the postharvest quality and preservation of pitaya fruits stored under refrigeration (12 °C). The fruits were subjected to different treatments and evaluated for biometric and physicochemical parameters, including weight loss, total soluble solids, pH, titratable acidity, and the SS/TA ratio throughout storage. The results demonstrated that the coatings significantly reduced weight loss (e.g., 4.15% for the CH4AA treatment) and contributed to the maintenance of quality attributes, delaying senescence-associated processes. Among the treatments, the combination of chitosan with ascorbic acid was the most effective in preserving fruit quality, extending the marketable shelf life from 10 to 20 days. These findings indicate that the use of biopolymeric coatings is a promising strategy to prolong the shelf life and maintain the postharvest quality of pitaya, with potential applications in commercial supply chains.

High air temperatures and intense solar radiation in semi-arid regions may impose thermal and photooxidative challenges on cacti. This study evaluated the physiological responses of white-fleshed (Hylocereus undatus) and red-fleshed (Hylocereus costaricensis) pitaya to foliar application of calcium sources and sunscreens. The experiment used a randomized block design (4 × 2 factorial) and tested four strategies (control, SunGard^®, calcium silicate, and Bordeaux mixture) on the two pitaya species. In red-fleshed pitaya, Bordeaux mixture was associated with the highest contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids, with increases of approximately 101.3%, 114.4%, 108.3%, and 99.4%, respectively, relative to the control, while reducing energy dissipation (DI₀/RC = 0.42) and increasing the photosynthetic performance index (PIabs) by 62.0%. In contrast, white pitaya showed a marked increase in the quantum yield of dissipation (φD₀) and DI₀/RC (1.53 with Bordeaux mixture), indicating treatment-dependent changes in excitation-energy partitioning. Maximum photochemical efficiency (Fv/Fm) remained high in both species (approx. 0.81–0.84) under calcium silicate and SunGard^® treatments. Foliar mineral formulations modified photosynthetic pigment contents and fluorescence responses in a species-dependent manner under semi-arid field conditions; the observed changes do not, by themselves, establish increased thermotolerance. Overall, the foliar formulations elicited distinct species-dependent responses in pigment accumulation, energy dissipation, and PSII photochemical performance under the recorded semi-arid field conditions.