Caroline Pardine Cardoso

Physalis peruviana L., a South American species, has been increasingly cultivated because of its bioactive compounds and high commercial value. This study evaluated the biochemical responses and fruit quality of physalis plants subjected to different water availability regimes (40%, 70%, and 100% of field capacity), followed by recovery periods. The experiment was conducted at São Paulo State University in a randomized block design with split plots. Plants were exposed to different irrigation regimes and subsequently rewatered over a 120-day period. Leaf and fruit analyses showed that water stress at 40% field capacity significantly increased both enzymatic and non-enzymatic antioxidant levels, thereby mitigating oxidative damage, as indicated by lower lipid peroxidation and reduced reactive oxygen species accumulation. However, this defense response was accompanied by marked reductions in fruit yield, fruit number, fresh mass, and fruit quality. Notably, although rewatering reversed several biochemical stress markers at the leaf level, fruit yield and commercial quality did not recover, suggesting irreversible damage to reproductive development during the stress period. These findings indicate that controlled water deficit may enhance antioxidant accumulation, highlighting the potential of stressed plants for pharmaceutical or nutraceutical applications. However, prolonged water stress, even when followed by a recovery period, impairs commercial fruit production. Therefore, irrigation management should be aligned with the intended production objective.

Vaccinium corymbosum L. ‘Biloxi’ is a cultivated blueberry variety valued for its rich content of phenolic compounds, which contribute to its strong antioxidant activity and recognized health benefits. There is little information on the effects of GA₃ and BA on blueberry, especially when used in combination. This study aimed to evaluate whether GA₃ and BA alter the yield and quality of V. corymbosum ‘Biloxi’ fruits. The experiment included 12 treatments consisting of GA₃ (25, 50 and 100 mg L⁻¹) and BA concentrations (50 and 100 mg L⁻¹) alone and combined and a control. The following parameters were analyzed: yield (g) and number of fruits per plant, mass, diameter, pH, soluble solids (SS), titratable acidity (TA), soluble sugars, total phenols, flavonoids, anthocyanins and antioxidant activity. The results indicate that foliar GA₃ and BA application improved the antioxidant capacity and biochemical composition of fruits, without negatively affecting production traits such as yield, fruit size or maturation period. The increases in antioxidant activity, phenol metabolites (total phenols, anthocyanins and flavonoids), soluble sugars, SS and SS/TA ratio were higher with the combination of GA₃ and BA at 100 mg L⁻¹. These results suggest that the combination of GA₃ and BA is a promising approach to sustainably improve fruit quality in commercial blueberry cultivation, providing both economic and nutritional benefits.

Water limits may have a disastrous impact on agricultural productivity, and the current climate change scenario presents additional problems for crops that rely on regular rainfall. Reactive oxygen species, such as hydrogen peroxide (H₂O₂), are a recognized stress-sensing mechanism in plants, and may be investigated as an approach for reducing stress impact via systemic acquired acclimation. Here, we looked at how H₂O₂ foliar application impacts tomato plants’ photosynthetic activity, antioxidant system, sugar chemical profile, and osmotic adjustment during drought and recovery. The experiment was in randomized blocks, 3 × 2 factorial design, with no, one, or two foliar application of 1 mM H₂O₂, on plants that were either continually watered or subjected to drought. The plants were tested both during the drought period and after they had resumed irrigation (recovered). Leaf water potential, chlorophyll a fluorescence, gas exchange, lipid peroxidation, H₂O₂ concentrations, phenols, proline, antioxidant enzyme activity, and sugar chemical profile were all measured. Our findings showed that H₂O₂ application generated metabolic alterations in tomato plants independent of water status, and that two applications in drought plants resulted in a 30% decrease in oxidative stress during drought and faster recovery following irrigation return, with greater production of defence-related molecules such as the APX enzyme, phenols, arabinose, and mannose. Continually watered plants also benefited from H₂O₂ application, which increased carbon assimilation by 35%.

The limited scion-rootstock combinations used in sweet orange orchards in Brazil reduce the commercial potential of citrus and lead to greater susceptibility to pests and diseases. Aiming to provide germplasm diversification, the research evaluated the Folha Murcha (FM) and Charmute de Brotas (CB) orange trees grafted onto ‘Rangpur’ lime (RL) and ‘Swingle’ citrumelo (SC) rootstocks. The study was conducted in the southern center of the state of São Paulo, in the subtropical region of southeastern Brazil. The grafted trees were planted in September 2016. The field experiment was conducted over two seasons. The combinations were evaluated based on the duration in days and degree-days of the phenological intervals, growth and yield performance, alternate bearing, fruit ripening, and quality. The trees of the two scion cultivars grafted onto RL had the shortest crop cycle, the earliest fruit ripening, and the largest canopy volume. SC produced fewer alternate bearings with greater production efficiency. The CB/SC combination produced fruits with a better color index, higher total soluble solids content, and a higher technological index. This assessment can be useful in planning orchards for dual-purpose markets, such as table fruit and the juice industry.

Atemoya (Annona × atemoya Mabb.), a climacteric fruit of the Annonaceae family, is becoming increasingly popular due to its organoleptic and nutritional properties. Anthracnose, a fungus of the Colletotrichum genus, is one of the most serious diseases in orchards, causing significant damage if not controlled, so producers use phytosanitary products. The current study sought to investigate the quality of atemoya fruits after harvest in an orchard with anthracnose controlled by Cu(OH)² application: T1—no Cu(OH)², T2—7.8 mL Cu(OH)² L1 divided into two applications, T3—15.6 mL Cu(OH)² L1 divided into four, T4—8.0 mL Cu(OH)² L1 divided into eight, and T5—13.0 mL Cu(OH)² L1 divided into thirteen applications. The sugar profile of fruits was examined, as well as MDA, H₂O₂, and quality parameters such as pH, mass, soluble solids, titratable acidity, and maturation index. MDA, such as H₂O₂, can function as a signal molecule. Eight applications of 1.0 mL L-1 Cu(OH)² resulted in increased concentrations of H₂O₂ and MDA, signal molecules involved in sugar modification profiles such as glucose, fructose, and trehalose. It also had a high titratable acidity, a lower maturation index, better fruit quality, and a longer shelf life.