https://repositorio.uema.br/jspui/handle/123456789/6298 2026-09-21T23:34:09Z https://repositorio.uema.br/jspui/handle/123456789/6690 Título: Aspectos fisiológicos de Cedrela fissilis Vellozo germinada in vitro sob condições de ventilação natural Abstact: Deforestation and rising atmospheric CO₂ levels threaten valuable tree species such as Cedrela fissilis. In this context, in vitro culture associated with natural ventilation in photoautotrophic and photomixotrophic systems represents a promising alternative for its conservation. Therefore, it is relevant to investigate how different in vitro cultivation strategies may affect the performance of this species under controlled conditions. This study aimed to evaluate the effects of photoautotrophic and photomixotrophic systems with natural ventilation on the development and physiological and anatomical characteristics of C. fissilis plants germinated in vitro. Seeds were disinfected and inoculated under different growing conditions, and two experiments were conducted: (E-I) a 2 × 2 × 2 factorial design evaluating sucrose concentrations (0 or 20 g L⁻¹), agar (0 or 5.5 g L⁻¹), and porous membranes (absence or presence). Germination parameters (% germination, % seedling formation, mean germination time—MGT, and mean seedling formation time—MSFT), growth traits (hypocotyl, shoot and primary root length; number of leaves, nodes, and roots), photosynthetic pigment contents, and anatomical traits (micromorphometry) were assessed. (E-II) a 2 × 2 factorial design evaluating the number of porous membranes (2 or 4) and CO₂ concentration ([CO₂], 420 or 800 ppm). The same growth and physiological analyses as in E-I were performed, with the addition of relative water content (RWC). In E-I, the presence of porous membranes enhanced seedling development in both culture media, particularly in the semisolid medium, which produced plants with superior growth and intense leaf greening even without sucrose supplementation. Sucrose supplementation (20 g L⁻¹) promoted improved plant development, especially when combined with membranes, resulting in greater fresh and dry biomass of shoots and roots, increased hypocotyl and shoot length, higher numbers of nodes and roots, and greater leaf area. Additionally, the membrane significantly increased chlorophyll b and carotenoid concentrations in C. fissilis plants. In E-II, increasing [CO₂] to 800 ppm and higher membrane permeability (four membranes) promoted greater shoot growth, higher dry biomass, larger leaf area, and increased numbers of lateral roots. Maximum root length and stem diameter were not affected, whereas root diameter varied depending on the interaction between CO₂ and permeability. Photochemical parameters (Fv/Fm, Fv/F₀, RC/ABS, and PI) remained stable, indicating preserved photosystem II functionality. Chlorophyll a and total chlorophyll contents increased with higher [CO₂] and permeability, whereas chlorophyll b remained unchanged. Carotenoids showed variable responses, with reductions under high permeability and elevated CO₂. Overall, combining porous membranes with semisolid medium, sucrose supplementation, elevated [CO₂] (800 ppm), and higher membrane permeability enhanced growth, biomass accumulation, and physiological performance of C. fissilis in vitro without impairing photochemical function. These strategies optimize the cultivation environment and support the micropropagation and acclimatization of the species. 2025-10-10T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6686 Título: Morfofisiologia da bananeira cv. Williams cultivada in vitro em diferentes intensidades da radiação fotossinteticamente ativa e concentrações de sacarose Abstact: The banana plant (Musa spp.) is a tropical fruit crop of great economic and social importance. However, the expansion of its cultivation is mainly limited by conventional propagation methods, making micropropagation a fundamental strategy for the largescale production of seedlings with high phytosanitary quality. In this context, adjusting the sucrose concentration and the intensity of photosynthetically active radiation (PAR) in in vitro cultivation contributes to optimizing photosynthetic efficiency and seedling growth. Thus, this work aimed to evaluate the impact of sucrose concentration and PAR on the photosynthetic machinery and in vitro growth of the ‘Williams’ banana plant, as well as the effects of these factors on the seedling acclimation phase. Thus, the experiment was conducted in a completely randomized design, in a 3x3 factorial scheme, corresponding to the combination of three sucrose concentrations (0, 15, and 30 g L⁻¹) with three PAR intensities (60, 120, and 180 μmol m⁻² s⁻¹). After 30 days of in vitro cultivation, growth, gas exchange, photochemical efficiency, pigments, and anatomical characteristics were evaluated. The results indicated that the total absence of sucrose, regardless of the PAR intensity, limited biomass production and seedling growth. However, treatments with the combination of 120 μmol m⁻² s⁻¹ of RFA and 15 g L⁻¹ of sucrose, and the treatment with the combination of 180 μmol m⁻² s⁻¹ and 30 g L⁻¹ of sucrose, provided improvements in the photosynthetic process and growth, with higher values of photosynthetic index and higher contents of photosynthetic pigments, and an increase in shoot length, leaf area, and shoot fresh mass. After the in vitro cultivation period, the seedlings were transferred to a greenhouse, where they remained for 30 days in the acclimatization phase. In this ex vitro phase, 100% seedling survival was observed, regardless of the treatments applied in the in vitro stage. However, the growth and vigor of seedlings under ex vitro conditions were influenced by the interaction between the intensity of PAR and the sucrose concentration used during in vitro cultivation, with better performance in treatments with 120 μmol m⁻² s⁻¹ associated with 15 g L⁻¹ of sucrose and 180 μmol m⁻² s⁻¹ associated with 30 g L⁻¹. Thus, it is concluded that the photomixotrophic cultivation of the banana var. ‘Williams’, under PAR of 120 and 180 μmol m⁻² s⁻¹ and with sucrose concentrations of 15 and 30 g L⁻¹, favors photosynthetic efficiency and growth, both in the in vitro phase and during acclimation, and constitutes an efficient strategy for micropropagation systems of this variety. 2026-02-26T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6649 Título: Enriquecimento com CO₂ no cultivo "in vitro" fotoautotrófico de abacaxis ‘Pérola’ e ‘Turipaz’: impactos na aclimatização, na anatomia e na fotossíntese Abstact: In vitro micropropagation is a widely used strategy for clonal plant multiplication; however, conventional culture systems impose physiological constraints associated with the artificial microenvironment, which limit carbon assimilation and delay the acquisition of autotrophy. In this context, CO􁁷 enrichment emerges as a promising approach to mitigate these limitations by inducing metabolic, anatomical, and functional adjustments in plants. Accordingly, the objective of this study was to evaluate the effects of CO􁁷 enrichment during photoautotrophic in vitro culture on growth, carbon-related attributes, and leaf micromorphometric traits of Ananas comosus cultivars ‘Pérola’ and ‘Turipaz’, as well as to assess how these responses are expressed during ex vitro acclimatization. The experiment was conducted in a completely randomized design in a 2 × 2 factorial arrangement, combining two cultivars (‘Pérola’ and ‘Turipaz’) and two [CO􁁷], aCO􁁷 420 ± 30 μmol mol⁻¹) and eCO􁁷 (800 ± 30 μmol mol⁻¹), for 50 days of in vitro culture, followed by 50 days of ex vitro acclimatization. CO􁁷 enrichment significantly increased shoot and root length, leaf number, rosette diameter, leaf area, and shoot fresh and dry biomass in both cultivars, while specific leaf mass was not affected. Root biomass exhibited a genotype-dependent response, with higher values in ‘Turipaz’ under aCO􁁷, whereas eCO􁁷 increased root fresh biomass only in ‘Pérola’, with no effect on root dry biomass. CO􁁷 enrichment increased chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid contents in both cultivars, with consistently higher total chlorophyll values in ‘Turipaz’. Photosynthetic performance was enhanced under eCO􁁷, as indicated by increases in net CO􁁷 A, gs, Ci, Ci/Ca, and PI, without changes in A/Ci or A/gs. TSC content increased markedly under eCO􁁷, with higher values in ‘Pérola’ at both [CO􁁷]. CO􁁷 enrichment promoted leaf anatomical modifications, including increased thickness of the epidermal layers, aquifer parenchyma, chlorophyll parenchyma, and vascular bundles, with tissue- and genotype-dependent responses under aCO􁁷 that were attenuated under eCO􁁷. During ex vitro acclimatization, plants derived from eCO􁁷-grown cultures maintained greater growth, biomass accumulation, pigment contents, total soluble carbohydrates, and part of the evaluated anatomical traits, with overall greater vigor observed in the cultivar ‘Turipaz’. In conclusion, CO􁁷 acts as a key variable in photoautotrophic in vitro micropropagation systems for pineapple by modulating plant morphophysiological trajectories during in vitro culture and positively conditioning plant performance during ex vitro acclimatization, reinforcing the importance of integrated approaches that consider functional continuity between these two phases of the propagation process 2026-02-23T00:00:00Z https://repositorio.uema.br/jspui/handle/123456789/6599 Título: Efeito do fotoperíodo na morfofisiologia de abacaxizeiro cultivado in vitro em sistema fotomixotrófico Abstact: Plants adjust their development to environmental variations through molecular mechanisms regulated by the circadian rhythm, with photoperiod being one of the main modulators of these processes. In this context, in vitro culture represents a strategic tool for investigating plant physiological plasticity and the interaction between photoperiod and the biological clock. In the state of Maranhão, the pineapple variety ‘Turiaçu’ shows agronomic potential, however, it faces limitations in the production of high-quality plantlets, making in vitro culture a viable alternative. Thus, this study aimed to evaluate the morphophysiological responses of pineapple plants from the ‘Pérola’ and ‘Turiaçu’ varieties cultivated in vitro under different photoperiods. The experiment was conducted in a completely randomized design, in a 2 × 4 factorial scheme, considering the two varieties and four photoperiods (4, 8, 16, and 24 h of light). Photoperiods of 8 and 16 h promoted greater root growth, leaf area expansion, biomass accumulation, and increased levels of photosynthetic pigments in both varieties, whereas the continuous 24 h photoperiod impaired growth and physiological efficiency, in addition to altering anatomical traits. It is concluded that intermediate photoperiods are the most suitable for the in vitro culture of the varieties studied, highlighting the central role of photoperiod in circadian regulation and plant morphophysiological plasticity 2026-02-20T00:00:00Z