Fábio Afonso Mazzei Moura de Assis Figueiredo

Water scarcity and elevated vapor pressure deficits pose significant challenges to papaya seedling production in tropical environments. To address this, the present study compared partial root-zone drying (PRD) and regulated deficit irrigation (RDI) to evaluate their efficacy in reducing water consumption without compromising physiological performance or seedling quality. Papaya seedlings were cultivated in a split-root system under four distinct water regimes: full irrigation, PRD, RDI, and non-irrigation (NI). At 14 days after treatment onset, PRD reduced stomatal conductance and CO₂ assimilation relative to full irrigation while increasing leaf-level intrinsic water-use efficiency. Xylem sap pH did not differ significantly between PRD and full irrigation in the post hoc comparison. Electron flux allocated to carboxylation decreased under PRD, whereas flux allocated to oxygenation and the measured energy-partitioning ratios did not differ significantly among the irrigated treatments. At 21 days, PRD and RDI received approximately half the irrigation volume of the fully irrigated control and accumulated less total biomass. The Dickson Quality Index under PRD was intermediate and did not differ significantly from full irrigation, whereas RDI resulted in significantly lower seedling quality compared to the control. These findings demonstrate that while both deficit strategies saved 50% of water and reduced total biomass, PRD offers a clear ecophysiological advantage over homogeneous RDI by successfully maintaining seedling quality comparable to well-watered plants.

This study investigates whether exogenous biotin (vitamin B7) mitigates salinity-induced physiological limitations in Dizygostemon riparius , a medicinal species endemic to Maranhão, Brazil, grown in vitro. Salinity (50 mM NaCl) significantly restricts shoot growth, reduces shoot dry mass, and decreases leaf number. Gas exchange analyses demonstrate that the salinity-induced decline in photosynthesis is driven predominantly by non-stomatal limitations, as evidenced by reduced carboxylation efficiency and intrinsic water use efficiency, indicating biochemical constraints on carbon fixation. Biotin supplementation (16 mg L⁻¹) partially alleviates these effects, restoring photosynthetic performance and attenuating growth reductions under salinity. In contrast, photosynthetic pigment composition, maximum quantum efficiency of photosystem II (Fv/Fm), and leaf micromorphology remain stable across treatments, indicating that salinity does not induce photochemical impairment or structural damage. Untargeted metabolomic analysis revealed that salinity extensively reprograms primary metabolism, altering tricarboxylic acid cycle intermediates while promoting the accumulation of osmoprotective and secondary metabolites, consistent with metabolic adjustment to osmotic stress. Although biotin restored photosynthetic performance, it did not reverse the salt-induced metabolic reprogramming, suggesting that its protective effects arise from improved metabolic efficiency rather than changes in the stress-associated metabolome. These findings demonstrate that biotin modulates salinity responses primarily at the metabolic level, sustaining carbon assimilation and water use efficiency without anatomical or photochemical adjustment. The results highlight the sensitivity of D. riparius to salinity and identify biotin as a potential metabolic regulator of its photosynthetic resilience in vitro.

Soil salinity is an increasing constraint to crop production, yet little is known about the responses of culantro (Eryngium foetidum), a medicinal and culinary species of high economic value, to saline conditions. This study evaluated the effects of NaCl-induced salinity (0, 40, and 80 mM) on the growth, photosynthetic performance, pigment content, and vascular anatomy of E. foetidum cultivated in vitro. After 45 days, salinity significantly reduced shoot and root length, leaf number, chlorophyll fluorescence, net CO₂ assimilation, stomatal conductance, transpiration, carboxylation efficiency, and the contents of chlorophylls a and b, and carotenoids, with the strongest effects observed at 80 mM NaCl. In contrast, leaf area, biomass accumulation, specific leaf area, and intrinsic water-use efficiency were not significantly affected. Qualitative anatomical observations indicated apparent modifications in vascular organization under saline conditions, including narrower xylem vessels and phloem disorganization. Collectively, these findings demonstrate that salinity primarily impairs photosynthetic performance and vegetative growth while inducing morphological, physiological, and apparent anatomical responses in E. foetidum cultivated in vitro. This study provides the first integrated characterization of the responses of E. foetidum to in vitro salt stress, establishing a foundation for future investigations into the physiological mechanisms underlying salinity responses in this species.

‘Turiaçu’ is a pineapple variety native to the Amazon region with high commercial potential that remains unexplored. Its propagation traditionally relies on vegetative material from mother plants, which increases the risk of pathogen transmission. Temporary immersion bioreactors (TIBs) are an alternative for large-scale production of disease-free plantlets, but their efficiency depends on the optimization of culture conditions. This study aimed to evaluate the effects of photoautotrophic and photomixotrophic in vitro cultivation of ‘Turiaçu’ pineapple under different light intensities in TIBs, as well as the subsequent ex vitro acclimatization performance of the plants. Explants were cultivated under light intensities of 71 and 116 µmol m⁻² s⁻¹, in culture media containing 0–15 g L⁻¹ of sucrose. After 50 days of in vitro growth, biometric parameters, photosynthetic pigments, gas exchange, and leaf anatomy were evaluated. Following 30 days of ex vitro acclimatization, survival, growth, and physiological performance were analyzed. The presence of sucrose in the culture medium was the main factor influencing growth and photosynthetic performance. Photoautotrophic conditions stimulated photosynthetic capacity, whereas photomixotrophic cultivation promoted greater biomass accumulation, particularly under 71 µmol m⁻² s⁻¹. Both cultivation modes resulted in 100% survival after acclimatization, confirming the high physiological quality of the in vitro-derived plants. Overall, the combination of 15 g L⁻¹ sucrose and a light intensity of 71 µmol m⁻² s⁻¹ proved to be the most suitable condition for large-scale production of ‘Turiaçu’ pineapple plantlets in temporary immersion bioreactors.

In vitro propagation is an efficient technique for producing ‘Turiaçu’ pineapple (Ananas comosus var. comosus) plantlets, ensuring uniform and pathogen-free plants. However, the acclimatization phase remains challenging, requiring appropriate nutritional strategies, with nitrogen being a key element for plant growth and metabolism. This study evaluated the effects of foliar fertilization with urea as a nitrogen source on the acclimatization of in vitro-grown ‘Turiaçu’ pineapple plantlets, using a completely randomized design with five foliar-applied urea concentrations (0%, 0.25%, 0.5%, 1.0%, and 1.5%) and ten replications. After 72 days of acclimatization, growth (leaf area, number of leaves, length of D leaf, rosette diameter, shoot and root dry mass), physiological (chlorophylls, carotenoids, photochemical efficiency), and nutritional (leaf macro- and micronutrients) parameters were analyzed. Foliar application of 1.0% urea promoted increases of 86.3% in leaf area, 38.7% in D leaf length, 30% in rosette diameter, 83% in shoot dry mass, and 13% in root dry mass, without causing phytotoxicity to the plantlets. It is concluded that foliar application of 1.0% urea is recommended to optimize the acclimatization of in vitro cultivated ‘Turiaçu’ pineapple plantlets, representing a promising approach for the commercial production of vigorous plantlets and for guiding future studies on foliar nutrition in bromeliads.

Plants possess several molecular mechanisms that enable them to adapt their development to environmental changes. Many plant biological processes depend on the circadian rhythm and are regulated by the internal biological clock. Predictable environmental changes, such as variations in photoperiod, can modulate circadian rhythms, allowing organisms to synchronize their biological processes with seasonal conditions. Plant tissue culture is a valuable tool for investigating and monitoring plant plasticity in response to environmental fluctuations, as well as for elucidating the biological changes that occur under these conditions. This review highlights the importance of in vitro culture as a tool to study the physiological plasticity triggered by photoperiod and its interaction with the plant biological clock. To achieve this, a descriptive analysis was conducted through a literature search in the Scopus database, followed by a bibliometric analysis to demonstrate the progress in the application of in vitro culture to studies on photoperiod and circadian regulation in plants.

Dizygostemon riparius is an endemic tropical Brazilian species whose physiological responses to salinity are poorly understood. This study evaluated the effects of NaCl (0, 50, and 100 mM) on in vitro-grown D. riparius by integrating growth, anatomical, photosynthetic, and biochemical analyses. Salinity significantly reduced biomass and growth parameters, indicating impaired development. Photosystem II efficiency declined, as evidenced by decreases in the performance index and chlorophyll content, while anatomical changes such as epidermal thickening and reduced vascular bundles reflected structural adjustments under stress. At the biochemical level, salinity altered polyamine metabolism, with reductions in total free polyamines, suggesting potential limitations in defense mechanisms. Hyperhydricity observed under high salinity indicated a non-adaptive response. Overall, D. riparius displayed limited tolerance to salt stress, with physiological and biochemical impairments outweighing structural plasticity. This study provides the first data-driven characterization of salinity effects in this species and highlights the value of in vitro culture as a tool to investigate stress responses.

Aim: This study aimed to identify the key bioclimatic factors driving the distribution of the Babassu Complex across the Neotropics in the current scenario (2011–2040), and to project their range shifts under future climate scenarios (2041–2070 and 2070–2100). Taxon: Babassu Complex (Arecaceae): Attalea barreirensis , A. eichleri , A. funifera , A. maripa , A. phalerata , A. speciosa , and A. vitrivir . Location: Neotropical region. Methods: We employed Species Distribution Modelling using four algorithms: Maximum Entropy (MaxEnt), Random Forest (RF), Boosted Regression Trees (BRT), and Generalised Linear Models (GLM) for the seven babassu species and for the combined Babassu Complex dataset. GBIF presence‐only data was combined with CHELSA 2.1 bioclimatic variables from current and future scenarios to fit the models. Projections for 2041–2070 and 2071–2100 were derived for two high‐emission climate scenarios (SSP3 7.0 and SSP5 8.5), using an ensemble of five global climate models. Results: The RF and BRT algorithms provided more conservative predictions for the current scenario, while MaxEnt and GLM projected broader distributions. Temperature seasonality was the most important suitability predictor. Attalea maripa , A. phalerata , and A. speciosa showed the broadest suitability ranges, while A. funifera and A. vitrivir were most constrained. Future scenarios projected major suitability increases (up to 871.80% for the Complex under SSP5‐8.5 by 2071–2100), particularly in Amazonian and Cerrado regions. Only A. funifera and A. vitrivir showed declines (−8.55% and −20.97% respectively under SSP3‐7.0). Main Conclusions: We anticipate that climate change may favour babassu species that tolerate warmer and more variable conditions, promoting their expansion. While this may support restoration and livelihoods, unmanaged spread could disrupt local ecosystems. It is recommended that future research focus on incorporating anthropogenic variables, validating predictions with field data, and exploring species‐specific ecological responses to climate change.

Platonia insignis, a native tree from the Amazon, has a high market demand due to its various uses, such as producing pulps and ice creams from its fruit and furniture from its wood. This review aims to systematize the scientific knowledge about the species and explore the potential of biotechnology to elucidate its growth, development, and fruiting mechanisms. Databases such as the Web of Science, Scopus, the Brazilian Agricultural Research Database, and PubMed were consulted using keywords like “P. insignis”, “bacuri”, and “bacurizeiro”. Of the 67 selected articles, it was observed that rigorous research on P. insignis is limited. Current management is based on empirical observations, but biotechnology could expedite the domestication process. Additionally, studying medicinal compounds from P. insignis could open new economic opportunities, encourage germplasm conservation, and drive genetic breeding.