Water deficit or flooding can damage the photosynthetic and enzymatic metabolism in plants such as Eugenia myrcianthes Nied. Thus, knowledge of technologies that can mitigate stress damage is necessary for the ex-situ cultivation of these species. This study evaluates the potential of hydrogel (H) to mitigate water stress and assist in the recovery of E. myrcianthes seedlings under different water conditions. The seedlings were separated into three water regimes: R1 - continuous irrigation (control); R2 - intermittent stress, characterized by two stress cycles: water restriction followed by flooding (stress); and R3 - intermittent stress + hydrogel - Forth^® gel (stress + H). Evaluations occurred in six periods: zero time (T0), 1^st zero photosynthesis (P0), 1^st recovery (REC), 2^nd P0, 2^nd REC, and END. E. myrcianthes seedlings responded to water conditions with reduced CO₂ assimilation rate, transpiration, and stomatal conductance during stressful conditions. We observed decrease in the growth parameters of this species under stress, including leaf area and biomass. Under stress, independent of H, plants increased the activity of the enzymes superoxide dismutase, peroxidase, and the content of the amino acid proline. We observed recovery potential in most of the evaluated traits. E. myrcianthes seedlings showed morphophysiological changes due to water deficit and flooding. Still, hydrogel did not contribute to alleviating the effects of water deficit on gas exchange and did not affect flooding. Seedlings showed survival and resumption of metabolism and growth after stressful conditions. This demonstrates their resilience due to physiological plasticity, regardless of the use of hydrogel.

Water deficit to causes serious problems in the growth and development of plants, impairing their metabolism. Thus, it is necessary to use agents that can mitigate plant damage. This study assesses the potential of silicon to mitigate water deficit stress in Dipteryx alata Vogel seedlings and to help in their recovery after the resumption of irrigation. The study analyzed four water regimes: (I) Continuous irrigation; (II) Water deficit without Si; (III) Water deficit + 0.75 mL Si; and (IV) Water deficit + 1.50 mL Si. Seedlings were evaluated in four periods: (1) (T0 – time zero) at the beginning of the experiment, before irrigation suspension; (2) (P0) when the photosynthetic rates (A) of seedlings under irrigation suspension reached values close to zero, period in which irrigation was resumed; (3) (REC) when A reached values close to those of seedlings under continuous irrigation, characterizing the recovery period; and (4) (END) 45 days after REC, when seedlings were kept under continuous irrigation, similar to the control. Application of 0.75 mL Si alleviates damage to the photosynthetic apparatus of D. alata seedlings that remain longer under water deficit, and contributes to faster physiological recovery after the resumption of irrigation. D. alata seedlings have recovery potential after the stress period, regardless of Si application.

Cactus cladodes are consumed by humans in arid and semiarid regions of the world. The use of biofertilizers when cultivating cacti can improve the physical and chemical characteristics of the soil, as well as the cladodes’ productivity and physical-chemical quality. We evaluated the physical and physical-chemical qualities of different lengths of Opuntia stricta (Haw.) Haw. Cladodes were grown with different biofertilizer doses. The 3 × 5 factorial design employed corresponded to three cladode sizes (8–12, 12–16, and 16–20 cm) and five doses of biofertilizer (0, 5, 10, 15, and 20%) with three repetitions in a completely randomized design. Cladode characteristics were evaluated 40 days after emergence: diameter, fresh mass, soluble solids, pH, titratable acidity, soluble solid and titratable acidity ratio (SS/TA), ascorbic acid, phenolic compounds, total soluble sugars, chlorophyll a, b, and total, carotenoids, and respiration. The Opuntia stricta cladodes sized 16–20 cm exhibited better physical and physical-chemical qualities as well as better respiratory rates. The biofertilizer improved the cladodes’ physical and physical-chemical qualities, regardless of the cladode’s size. Opuntia stricta (Haw.) Haw. cladodes had levels of antioxidant compounds similar to those of some conventional vegetables, making them suitable for improving human health in arid environments.

The use of microalgae has been proeminent in agricultural scenario, because it is an alternative product considered extremelly productive, which contains essential elements for plants. Thus, this study aimed to evaluate the morphophysiology of Punica granatum L. seedlings treated with Spirulina platensis and Scenedesmus sp. nanoparticles in controlled environment. The research was carried out at the of Federal University of Campina Grande, Pombal-PB, using a completely randomized design with five replications. The factorial scheme (2 x 4) was adopted, represented by two types of microalgae (Spirulina platensis; Scenedesmus sp.) and four doses of application (0, 5, 10 and 15%). Growth evaluations happened at 135 days after planting, verifying the number of leaves and branches and shoot length. The physiological parameters evaluated were gas exchanges, chlorophyll ‘a’ fluorescence, electron transport rate, stationary fluorescence, maximum fluorescence yield after light adaptation and quantum efficiency of PSII. Shoot length and number of branches had rises at doses of 6 and 15%. Number of leaves was induced in seedlings at dose of 8% with Spirulina platensis. Stomatal conductance and internal CO2 concentration increased in seedlings sprayed with Spirulina platensis. extract of Scenedesmus sp. improved the stationary fluorescence and quantum efficiency of PSII in pomegranate seedlings. The use of microalgae has been proeminent in agricultural scenario, because it is an alternative product considered extremelly productive, which contains essential elements for plants. Thus, this study aimed to evaluate the morphophysiology of Punica granatum L. seedlings treated with Spirulina platensis and Scenedesmus sp. nanoparticles in controlled environment. The research was carried out at the of Federal University of Campina Grande, Pombal-PB, using a completely randomized design with five replications. The factorial scheme (2 x 4) was adopted, represented by two types of microalgae (Spirulina platensis; Scenedesmus sp.) and four doses of application (0, 5, 10 and 15%). Growth evaluations happened at 135 days after planting, verifying the number of leaves and branches and shoot length. The physiological parameters evaluated were gas exchanges, chlorophyll ‘a’ fluorescence, electron transport rate, stationary fluorescence, maximum fluorescence yield after light adaptation and quantum efficiency of PSII. Shoot length and number of branches had rises at doses of 6 and 15%. Number of leaves was induced in seedlings at dose of 8% with Spirulina platensis. Stomatal conductance and internal CO2 concentration increased in seedlings sprayed with Spirulina platensis. extract of Scenedesmus sp. improved the stationary fluorescence and quantum efficiency of PSII in pomegranate seedlings.

Organic fertilization can promote greater production of cladodes as well as increase phytomass production and the quality and content of bioactive compounds. Thus, the aim of this study was to evaluate the sources and doses of organic fertilizer on the production and quality of forage palm cladodes. A completely randomized experimental design in a 3 × 3 factorial scheme with five replications was used. Three sources of organic fertilizer (chicken manure, cattle manure, and goat manure) and three concentrations of each source (0, 10, and 20%) were studied. Cladodes fresh mass, pH, soluble solids, titratable acidity, soluble solids/titratable acidity ratio, ascorbic acid, chlorophyll, carotenoids, phenolic compounds, flavonoids, and anthocyanins were evaluated. Palm cladodes fertilized with 20% chicken manure produce the highest biomass, while cladodes fertilized with 10% chicken manure have the highest palatability and content of bioactive compounds. Thus, fertilization with 10% chicken manure is the most promising and economically viable way to increase the production and quality of palm cladodes. The research demonstrated that fertilization with chicken, cattle, and goat manure increases the productivity, nutritional quality, and palatability of the cladodes intended for human consumption, providing a sustainable and healthy alternative for the region.

Water deficit is a stressful condition that negatively affects photosynthetic metabolism and plant growth. In an attempt to alleviate the effect of low water availability, the use of water-retaining polymer (hydrogel) has proven to be a viable strategy. We aimed to evaluate the effect of the hydrogel on photosynthetic metabolism and antioxidant protection in Dipteryx alata Vogel. seedlings under water deficit and on potential recovery in post-stress. The seedlings grown under the following water regimes: i) control – irrigated daily, ii) water deficit – suspension of irrigation, and iii) water deficit + hydrogel – addition of polymer in the time of transplanting. Assessments were carried out at photosynthesis close to zero and at recovery (resumption of irrigation after). We observed decreased in gas exchange and growth of seedlings subjected to water deficit in photosynthesis close to zero, but those with hydrogel maintained high values, in addition to a more efficient recovery. Although the hydrogel did not contribute to chlorophyll a fluorescence, it favored enzymatic regulation similar to control plants, especially peroxidase in leaves and roots, and superoxide dismutase in roots. D. alata responds to water deficit activating protective mechanisms through physiological and antioxidants adjustments that ensure its survival when exposed to water deficit and its recovery post-stress, indicating phenotypic plasticity. The hydrogel contributes positively to the photosynthetic, enzymatic, and quality maintenance of D. alata seedlings during and after stress.