RESUMO
Date palm (Phoenix dactylifera( cv. Medjool is a significant plant, grown in Jordan. In vitro propagation gives operative resources for the significant propagation of date palms. Maximum callus induction was achieved from MS media supplemented with benzyl amino purine (BA) and naphthalene acetic acid (NAA). The highest plant regeneration was recorded on MS medium supplemented with dichlorophenoxyacetic acid (2,4-D) at 3.0 mg/L, and BA at 2.0 mg/L. A significant positive impact on shoot formation was recorded on MS medium supplemented with 1.0 mg/L BA with 0.5 to 1.5 mg/L NAA in both liquid and solid MS medium. To maintain survival and regrowth capacity, sucrose could be used for medium-term conservation at lower concentrations (0.1 - 0.2 M). In addition, sorbitol might be used at 0.1 M to maintain the quality of explants. The vitrification technique for long-term preservation was experimented. Embryogenic callus was used as explants for conservation. The survival as well as regrowth percentages of non-cryopreserved and cryopreserved tissue cultures were affected by their duration of treatment with the vitrification solution plant vitrification solution 2 (PVS2) and modified plant vitrification solution 2 (MPVS2). Results showed that using PVS2 for 60 minutes for cryopreserved calli was more effective than other treatments. After storage in liquid nitrogen, the highest survival rate (65%) and regrowth rate (40%) were achieved.
Assuntos
Phoeniceae , Brotos de Planta , Regeneração , Phoeniceae/fisiologia , Phoeniceae/efeitos dos fármacos , Regeneração/fisiologia , Regeneração/efeitos dos fármacos , Brotos de Planta/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/efeitos dos fármacos , Meios de Cultura , Reguladores de Crescimento de Plantas/farmacologia , Criopreservação , Técnicas de Cultura de TecidosRESUMO
We tested an approach to estimate daily canopy net photosynthesis, A, based on estimates of transpiration, E, using measurements of sap flow and water-use efficiency, ω, by measuring δ13C in CO2 respired from shoots in the canopies of two conifers (Podocarpaceae) native to New Zealand. The trees were planted in adjacent 20-year-old stands with the same soil and environmental conditions. Leaf area index was lower for Dacrycarpus dacrydioides D.Don in Lamb (1.34 m2 m-2) than for Podocarpus totara G.Benn. ex D.Don var. totara (2.01 m2 m-2), but mean (± standard error) stem diameters were the same at 152 ± 21 mm for D. dacrydioides and 154 ± 25 mm for P. totara. Over a 28-day period, daily A (per unit ground area) ranged almost five-fold but there were no significant differences between species (mean 2.73 ± 1.02 gC m-2 day-1). This was attributable to higher daily values of E (2.63 ± 0.83 mm day-1) and lower ω (1.35 ± 0.53 gC kg H2O-1) for D. dacrydioides compared with lower E (1.82 ± 0.72 mm day-1) and higher ω (1.90 ± 0.77 gC kg H2O-1) for P. totara. We attributed this to higher nitrogen availability and nitrogen concentration per unit foliage area, Na, and greater exposure to irradiance in the D. dacrydioides canopy compared with P. totara. Our findings support earlier observations that D. dacrydioides is more adapted to sites with poor drainage. In contrast, the high retention of leaf area and maintaining low rates of transpiration by P. totara, resulting in higher water-use efficiency, is an adaptive response to survival in dry conditions. Our findings show that physiological adjustments for two species adapted to different environments led to similar canopy photosynthesis rates when the trees were grown in the same conditions. We demonstrated consistency between whole-tree and more intensive shoot-scale measurements, confirming that integrated approaches are appropriate for comparative estimates of carbon uptake in stands with different species.
Assuntos
Fotossíntese , Estômatos de Plantas , Água , Fotossíntese/fisiologia , Água/metabolismo , Água/fisiologia , Estômatos de Plantas/fisiologia , Brotos de Planta/fisiologia , Traqueófitas/fisiologia , Traqueófitas/metabolismo , Transpiração Vegetal/fisiologia , Adaptação Fisiológica , Árvores/fisiologia , Folhas de Planta/fisiologia , Folhas de Planta/metabolismo , Nova ZelândiaRESUMO
Temporary immersion systems (TIS) have been widely recognized as a promising technology for micropropagation of various plant species. The TIS provides a suitable environment for culture and allows intermittent contact of the explant with the culture medium at different immersion frequencies and aeration of the culture in each cycle. The frequency or immersion is one of the most critical parameters for the efficiency of these systems. The design, media volume, and container capacity substantially improve cultivation efficiency. Different TIS have been developed and successfully applied to micropropagation in various in vitro systems, such as sprout proliferation, microcuttings, and somatic embryos. TIS increases multiplication and conversion rates to plants and a better response during the ex vitro acclimatization phase. This article covers the use of different immersion systems and their applications in plant biotechnology, particularly in plant tissue culture, as well as its use in the massive propagation of plants of agroeconomic interest.
Assuntos
Aclimatação , Desenvolvimento Vegetal , Meios de Cultura/química , Técnicas de Cultura de Tecidos/métodos , Técnicas de Cultura de Tecidos/instrumentação , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/fisiologia , Plantas , Imersão , Técnicas de Embriogênese Somática de Plantas/métodosRESUMO
BACKGROUND AND AIMS: Desiccation tolerance (DT) is crucial for survival in arid environments, where organisms develop strategies in reproduction, maintenance and defence to cope with water scarcity. Therefore, investigating the relationship between reproduction and DT is essential to understand the ecology and adaptive strategies of species. This study explores the connection between the development of male and female gametangia in the moss Bryum argenteum and the decrease in DT during the progression of phenological phases in gametangia and protonema. METHODS: Samples collected from a dry tropical forest in Brazil were cultivated, cloned and subjected to desiccation. Subsequently, the physiological parameters of shoots and protonemata were analysed. Shoot and protonema regeneration were monitored for 28 d after the physiological analyses. Both phases were subjected to control and desiccation treatments. KEY RESULTS: Significant effects of desiccation and sex on the physiological parameters and regeneration capacity of shoots and protonemata were found. Male shoots generally exhibited lower values of Fv/Fm (quantum efficiency of photosystem II) and ÏPSII (effective quantum yield of photosystem II), while females demonstrated higher values and better recovery after desiccation. Protonemata also showed variation in Fv/Fm over time and with sex, with no significant differences in ÏPSII between them. Desiccated male shoots had higher mortality rates and produced fewer new shoots. For females, the regeneration patterns varied between the desiccation-exposed groups and the control, with decreased shoot production, and some protonemata growing into filaments without forming shoots. CONCLUSION: These findings improve our understanding of the ecological responses of bryophytes to desiccation stress and provide insights into their adaptive strategies in challenging environments, such as the possible rarity of males in dioicous moss populations.
Assuntos
Dessecação , Adaptação Fisiológica/fisiologia , Brotos de Planta/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Bryopsida/fisiologia , Reprodução/fisiologia , BrasilRESUMO
The objective of this study was to evaluate the effective temperature for overcoming the dormancy of 'Fuyu' persimmon tree buds. Stem samples were collected three times between 2013 and 2014. Stems were maintained in a climate incubator chamber at 3, 6, 9, and 12 °C. For each temperature, five numbers of additional chilling hours (CH) (0, 240, 384, 528, and 672 CH) were studied. The experimental design was completely randomized in a 5 × 4 factorial design (chilling hours × temperatures) with four replications with 10 cuttings. The maintenance of branches at cold temperatures from 3 to 12 °C intensified endodormancy of the buds when the plants were at the beginning of endodormancy. The most effective temperatures for overcome dormancy when the buds were in transition from paradormancy to endodormancy were from 3 to 6 °C. When the buds were already in endodormancy, temperatures of 3, 6, 9, and 12 °C were effective for the accumulation of cold and overcoming dormancy. The increase in the number of chilling hours from 3 to 12 °C induced budburst and the temperature of 12 °C was able to slowly induce and overcome bud dormancy.
Assuntos
Temperatura Baixa , Brotos de Planta/fisiologia , Diospyros , Dormência de Plantas/fisiologiaRESUMO
The light spectrum quality is an important signal for plant growth and development. We evaluated the effects of different light spectra on the in vitro shoot development of Cedrela fissilis and its proteomic and polyamine (PA) profiles. Cotyledonary and apical nodal segments were grown under different light emitting diodes (LED) and fluorescent lamps. Shoots from cotyledonary nodal segments cultured with 6-benzyladenine (BA) that were grown under WmBdR LED showed increased length and higher fresh and dry matter compared to shoots grown under fluorescent lamps. A nonredundant protein databank generated by transcriptome sequencing and the de novo assembly of C. fissilis improved, and almost doubled, the protein identification compared to a Citrus sinensis databank. A total of 616 proteins were identified, with 23 up- and 103 down-accumulated in the shoots under WmBdR LEDs compared to fluorescent lamps. Most differentially accumulated proteins in shoots grown under the WmBdR LED lamp treatment compared to the fluorescent lamp treatment are involved in responding to metabolic processes, stress, biosynthetic and cellular protein modifications, and light stimulus processes. Among the proteins, the up-accumulation of argininosuccinate synthase was associated with an increase in the free putrescine content and, consequently, with higher shoot elongation under WmBdR LED. The down-accumulation of calreticulin, heat shock proteins, plastid-lipid-associated protein, ubiquitin-conjugating enzymes, and ultraviolet-B receptor UVR8 isoform X1 could be related to the longer shoot length noted under LED treatment. This study provides important data related to the effects of the light spectrum quality on in vitro morphogenesis through the modulation of specific proteins and free putrescine biosynthesis in C. fissilis, an endangered wood species from the Brazilian Atlantic Forest of economic and ecological relevance. The nonredundant protein databank of C. fissilis is available via ProteomeXchange under identifier PXD018020.
Assuntos
Cedrela/fisiologia , Cedrela/efeitos da radiação , Luz , Brotos de Planta/fisiologia , Brotos de Planta/efeitos da radiação , Poliaminas/metabolismo , Proteoma/efeitos da radiação , Cedrela/crescimento & desenvolvimento , Germinação , Espectrometria de Massas , Desenvolvimento Vegetal/efeitos da radiação , Brotos de Planta/crescimento & desenvolvimento , Proteômica/métodosRESUMO
Understanding nanoparticle root uptake and root-to-shoot transport might contribute to the use of nanotechnology in plant nutrition. This study performed time resolved experiments to probe Zn uptake, biotransformation and physiological effects on Phaseolus vulgaris (L.). Plants roots were exposed to ZnO nanoparticles (40 and 300 nm) dispersions and ZnSO4(aq) (100 and 1000 mg Zn L-1) for 48 h. Near edge X-ray absorption spectroscopy showed that 40 nm ZnO was more easily dissolved by roots than 300 nm ZnO. It also showed that in the leaves Zn was found as a mixture Zn3(PO4)2 and Zn-histidine complex. X-ray fluorescence spectroscopy showed that root-to-shoot Zn-translocation presented a decreasing gradient of concentration and velocity, it seems radial Zn movement occurs simultaneously to the axial xylem transport. Below 100 mg Zn L-1, the lower stem tissue section served as a buffer preventing Zn from reaching the leaves. Conversely, it was not observed for 1000 mg Zn L-1 ZnSO4(aq). Transcriptional analysis of genes encoding metal carriers indicated higher expression levels of tonoplast-localized transporters, suggesting that the mechanism trend to accumulate Zn in the lower tissues may be associated with an enhanced of Zn compartmentalization in vacuoles. The photosynthetic rate, transpiration, and water conductance were impaired by treatments.
Assuntos
Nanopartículas/metabolismo , Phaseolus/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Óxido de Zinco/metabolismo , Zinco/metabolismo , Metais/metabolismo , Phaseolus/genética , Phaseolus/fisiologia , Fotossíntese/fisiologia , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Brotos de Planta/fisiologia , Transcrição Gênica/genética , Espectroscopia por Absorção de Raios X/métodosRESUMO
Salinity stress limited the production in over 30% of irrigated crops and 7% of dryland agriculture worldwide. The objective was to evaluate the effects of NaCl-stress on the enzymatic activity in tomato. Two experiments were carried out in germination and early vegetative growth stages. The activity of proline and peroxidase of eight varieties (Missouri, Yaqui, Vita, Feroz, Rio Grande, Tropic, Ace, and Floradade) submitted to NaCl concentrations (0, 50, 100, 150 and 200 mM de NaCl) and the semi-quantitative activity of 19 enzymes APY ZYM® were measured under a completely randomized design with four replications. Data were analyzed using univariate-multivariate analysis of variance, Tukey's HSD (p = 0.05), canonical discriminant and cluster analysis. The results showed significant differences between varieties and NaCl in proline content. Proline increased as the NaCl concentration increased. Peroxidase did no show significant differences. Eight enzymes were included within the model to properly classify the varieties and NaCl. In shoots, varieties and NaCl showed that enzymatic activity was higher in the order of alkaline-phosphatase > leucine arylamidase > acid phosphatase > naphthol-AS-BI-phosphohydrolase > n-acetyl-ß-glucosaminidase > ß-galactosidase, while in roots was higher in the order of alkaline-phosphatase > naphthol-AS-BI-phosphohydrolase > acid phosphatase > n-acetyl-ß-glucosaminidase. Acid and alkali phosphatase, lipase, esterase, ß-galactosidase, and trypsin can be a potential biomarker for NaCl-stress tolerance in tomato.
Assuntos
Esterases/metabolismo , N-Glicosil Hidrolases/metabolismo , Peptídeo Hidrolases/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Tolerância ao Sal , Cloreto de Sódio/farmacologia , Solanum lycopersicum/efeitos dos fármacos , Solanum lycopersicum/fisiologia , Biomarcadores , Análise por Conglomerados , Ativação Enzimática , Brotos de Planta/fisiologia , Prolina/metabolismo , Proteoma , Proteômica , Plântula/fisiologiaRESUMO
OBJECTIVES: This study was conducted to establish a method for early, quick and cheap screening of iron excess tolerance in rice (Oryza sativa L.) cultivars. RESULTS: Based on the experiments, iron excess leads to reduction in shoot length (SL) and this can be a useful characteristic for adequate screening of tolerant genotypes. The sensitive genotypes Nipponbare and BR-IRGA 409 indicated higher accumulation of iron in their tissues while BRS-Agrisul and Epagri 108 also accumulated iron, but at lower concentrations. BR-IRGA 410 displayed an intermediate phenotype regarding iron accumulation. No changes in shoot Cu content can be observed when comparing treatments. On the other hand, an increase was seen for Zn and Mn when shoots are subjected to Fe2+ excess. Fe stress at a lower concentration than 7 mM increased Zn but decreased Mn contents in shoots of BR-IRGA 409. Strong positive correlations were found here for Fe × Zn (0.93); Fe × Mn (0.97) and Zn × Mn (0.92), probably due to the Fe-induced activation of bivalent cation transporters. Results show that genotypes scored as sensitive present higher concentration of Fe in shoots and this is an efficient method to characterize rice cultivars regarding iron response.
Assuntos
Adaptação Fisiológica/genética , Testes Genéticos , Ferro/toxicidade , Oryza/genética , Oryza/fisiologia , Adaptação Fisiológica/efeitos dos fármacos , Genótipo , Oryza/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/fisiologia , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/fisiologiaRESUMO
The fragmentary information on phosphorus (P) × zinc (Zn) interactions in plants warrants further study, particularly in plants known for their high P and Zn requirements, such as cotton (Gossypium hirsutum L.). The objective of this study was to investigate the effect of P × Zn interactions in a modern cultivar of cotton grown hydroponically. Biomass, mineral nutrition and photosynthetic parameters were monitored in plants receiving contrasting combinations of P and Zn supply. Root biomass, length and surface area were similar in plants with low P and/or low Zn supply to those in plants grown with high P and high Zn supply, reflecting an increased root/shoot biomass quotient when plants lack sufficient P or Zn for growth. Increasing P supply and reducing Zn supply increased shoot P concentrations, whilst shoot Zn concentrations were influenced largely by Zn supply. A balanced P × Zn supply (4 mM P × 4 µM Zn) enabled greatest biomass accumulation, while an imbalanced supply of these nutrients led to Zn deficiency, P toxicity or Zn toxicity. Net photosynthetic rate, stomatal conductance, transpiration rate and instantaneous carboxylation efficiency increased as P or Zn supply increased. Although increasing P supply reduced the P-use efficiency in photosynthesis (PUEP) and increasing Zn supply reduced the Zn-use efficiency in photosynthesis (ZnUEP), increasing Zn supply at a given P supply increased PUEP and increasing P supply at a given Zn supply increased ZnUEP. These results suggest that agricultural management strategies should seek for balanced mineral nutrition to optimize yields and resource-use efficiencies.