Post-harvesting longevity of bird of paradise (Strelitzia spp.) treated with carnauba wax

  Strelitzias are tropical plants that have shown great interest in the market and can be used in landscaping in tropical floral arrangements. Aiming to extend its postharvest life, the objective of the work was to evaluate different concentrations of the commercial product based on carnauba wax in the postharvest longevity of Strelitzia juncea and Strelitzia reginae leaves. The experiment was conducted in a completely randomized design with five treatments and six repetitions, with one leaf per repetition for each species. The concentrations used were: 0% (control), 2%, 20%, 40% and 100%. The loss of leaf mass (%) and the visual quality of the leaves were evaluated through the criterion of notes, in addition to making use of anatomical analyzes of the stomatal structures of the leaves through scanning microscopy. The loss of mass was reduced with the increase of the wax concentration, however, high doses provided increased loss. The use of carnauba wax proved efficient at concentrations of 20 and 40%, maintaining the commercial quality of the leaves of S. reginae and S. juncea until the 24th day, while in the control treatment, the leaves maintained a commercial pattern until the 16th for S. reginae and 18th day for S. juncea. The deposition of wax in the stomatal structures may have influenced the loss of mass of both species as observed by scanning microscopy.As Strelitzias são plantas tropicais que têm despontado grande interesse do mercado, podendo ser utilizadas no paisagismo em arranjos florais tropicais. Visando ampliar sua vida pós-colheita, o objetivo do trabalho foi avaliar diferentes concentrações do produto comercial a base de cera de carnaúba na longevidade pós-colheita de folhas de Strelitzia juncea e Strelitzia reginae. O experimento foi conduzido em delineamento inteiramente casualizado com cinco tratamentos e seis repetições, com uma folha por repetição para cada espécie. As concentrações utilizadas foram: 0% (controle), 2%, 20%, 40% e 100%. Avaliaram-se a perda de massa foliar (%) e a qualidade visual das folhas por meio do critério de notas, além de se fazer uso de análises anatômicas das estruturas estomáticas das folhas através de microscopia de varredura. A perda de massa foi reduzida com o aumento da concentração de cera, no entanto, altas doses proporcionaram aumento da perda. O uso de cera de carnaúba se mostrou eficiente nas concentrações de 20 e 40%, mantendo a qualidade comercial das folhas de S. reginae e S. juncea até o 24º dia, enquanto no tratamento controle, as folhas mantiveram padrão comercial até o 16° para S. reginae e 18° dia para S. juncea. A deposição de cera nas estruturas estomáticas pode ter influenciado na perda de massa de ambas as espécies conforme foi observado por meio da microscopia de varredura

In vitro control of phytopathogenic fungi and damping-off of tomato by Bacillus velezensis LABIM40 (CMRP 4489)

The in vitro antagonistic activity of Bacillus velezensis LABIM40 (strain CMRP 4489) was assessed against Alternaria linariae, Botryotinia squamosa, Colletotrichum lindemuthianum, Gibberella zeae, and Rhizoctonia solani. An experiment was conducted using treated seeds under growth chamber conditions to determine the impact of various LABIM40 formulations on tomato seedling growth and the biocontrol of damping-off caused by R. solani. The treatments included the use of LABIM40 cell suspension, LABIM40 cell-free supernatant (CFS), 10 times concentrated CFS (10× CFS), commercial products based on Bacillus amyloliquefaciens (CP_1) and Bacillus subtilis (CP_2), and water. The effects of these products were assessed on tomato seedlings grown in sterile substrate or substrate inoculated with R. solani. In a dual culture test, B. velezensis LABIM40 inhibited the mycelial growth of the aforementioned fungal pathogens by 46.6%, 67.4%, 64.7%, 49.0%, and 54.4%, respectively. The minimum inhibitory concentration against each fungus was determined using varying concentrations of CFS in potato dextrose agar medium, followed by a regression analysis of mycelial growth inhibition. Except for A. linariae, the logarithmic model provided the best fit in all cases. Tomato seedlings from seeds treated with 10× CFS in inoculated substrate exhibited a survival rate 57% higher than that exhibited by the control treatment. However, no growth promotion was observed in tomato plants from seeds treated with LABIM40 cells or its CFS metabolites. In summary, these findings highlight the antagonistic activity of B. velezensis LABIM40 against A. linariae, B. squamosa, C. lindemuthianum, G. zeae, and R. solani, as demonstrated by dual culture and CFS diffusion tests. This suggests its potential as a biocontrol agent for damping-off in tomatoes

Influence of film coefficient during multicomponent diffusion – KCl/NaCl in biosolid for static and agitated system using 3D computational simulation

Abstract The influence of film coefficient formed during the diffusion of inorganic salts (NaCl and KCl) in biosolids was studied using a 3D computer modeling by Finite Elements Method (FEM) in COMSOL Multiphysics® software combined with SOM-type Artificial Neural Networks (ANN). Such tools have shown that the influence of the film formed in the biosolid/solution interface occurs in a heterogeneous manner and is due to the matrix geometry, the type of system (agitated or static) and the ion size (Na+ or K+). The influence of film coefficient was more pronounced for K+ ion, and for a static system. Comparing the geometry of biosolids, ion diffusion was more pronounced in the (Y±) axis in relation to other axes, X (±) and Z (±), as well as in between the poles (±) of this axis. FEM simulation associated with SOM-type ANN were efficient tools to evaluate this complex and unknown biophysical phenomenon

PLANT GROWTH-PROMOTING MICROBIAL INOCULANT FOR Schizolobium parahyba pv. parahyba

ABSTRACTSchizolobium parahyba pv. amazonicum (Huber ex Ducke) Barneby (paricá) occurs naturally in the Amazon and is significant commercial importance due to its rapid growth and excellent performance on cropping systems. The aim of this paper was to evaluate a microbial inoculants such as arbuscular mycorrhiza fungi (AMF) and Rhizobium sp. that promote plant growth. The inocula was 10 g of root colonized and spores of Glomus clarum and/or 1 mL of cell suspension (107 CFU/mL) of Rhizobium sp. and/or 100 g of chemical fertilizer NPK 20-05-20 per planting hole. The experimental design was complete randomized blocks with five replications and eight treatments (n = 800). Plant height, stem diameter and plant survival were measured. The results were tested for normality and homogeneity of variances and analyzed by ANOVA and Tukey test (p < 0.05). Rhizobium sp and AM fungi showed no effect on plant growth. Environmental factors probably influenced the effectiveness of symbiosis of both microorganisms and plant growth. The chemical fertilizer increased S. parahyba growth. During the first 120 days plants suffered with drought and frost, and at 180 days plants inoculated with microorganism plus chemical fertilizer showed higher survival when compared with control. The results showed that the microbial inoculants used showed an important role on plant survival after high stress conditions, but not in plant growth. Also was concluded that the planting time should be between November to December to avoid the presence of young plants during winter time that is dry and cold

New Insights on Alternative Hosts of <i>Xanthomonas vasicola</i> pv. <i>vasculorum</i>, the Causal Agent of Bacterial Leaf Streak of Maize

Bacterial leaf streak (BLS) of maize (Zea mays), caused by the bacterium Xanthomonas vasicola pv. vasculorum (Xvv), was first reported in Brazil in 2018. In this study, we evaluated 52 species of cultivated plants, cover crops, forage, and grasses that are used in succession or crop rotation with maize, and weeds with natural occurrence in maize-producing regions, to determine their potentials as alternative hosts for Xvv. We investigated (i) the pathogenicity of Xvv based on symptom development, (ii) epiphytic colonization of the bacterium in asymptomatic plants, and (iii) bacterial colonization in plant tissues using scanning electron microscopy (SEM) in symptomatic and asymptomatic species. Ten species, all belonging to the Poaceae family, presented symptoms after Xvv infection, including Avena sativa (cvs. IPR Afrodite and IPR Esmeralda), A. strigosa (cv. IPR 161), Hordeum vulgare (cv. BRS Cauê), Oryza sativa (cv. IPR 117), Brachiaria brizantha (Brizantha and cv. Marandu), Digitaria horizontalis, D. insularis, Echinochloa colonum, Eleusine indica, and Sorghum arundinaceum. Furthermore, epiphytic colonization by Xvv was observed in 23 asymptomatic species. Scanning micrographs revealed that Xvv cells and their aggregates were distributed throughout the leaf surface. In addition, bacterial colonization in the intercellular tissues of the substomatal chambers of white oat, black oat, and maize was observed across the tissue fractures. Despite showing typical symptoms of Xvv infection, SEM examination revealed evidence of Xvv colonization only on the leaf surface of rice. In asymptomatic species, such as rye, sorghum, and millet, a low number of bacterial cells were found on the leaf surface. However, no evidence of internal tissue colonization was observed in millet fractures, suggesting that Xvv survives only epiphytically in this species

Inoculation of Schizolobium parahyba with mycorrhizal fungi and plant growth-promoting rhizobacteria increases wood yield under field conditions

Schizolobium parahyba var. amazonicum (Huber ex Ducke) occurs naturally in the Brazilian Amazon. Currently, it is being planted extensively because of its fast growth and excellent use in forestry. Consequently, there is great interest in new strategies to increase wood production. The interaction between soil microorganisms and plants, specifically in the roots, provides essential nutrients for plant growth. These interactions can have growth-promoting effects. In this way, this study assessed the effect of the inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on growth of S. parahyba var. amazonicum under field conditions. We used two native species of arbuscular mycorrhizal fungi, Claroideoglomus etunicatum (Ce) and Acaulospora sp. (Ac); two native strains of Rhizobium sp. (Rh1 and Rh2); and a non-native strain of Burkholderia sp. Different combinations of microorganisms were supplemented with chemical fertilizers (doses D1 and D2) in two planting methods, seed sowing and seedling planting. In seed sowing, the results showed that treatments with Ce/Rh1/Fertilizer D2 and Ac/No PGPR/Fertilizer D2 increased wood yield. In seedling planting, two combinations (Ac/Rh2/Fertilizer D1 and Ac/Rh1/Fertilizer D1) were more effective in increasing seedling growth. In these experiments, inoculation with AMF and PGPR increased wood yield by about 20% compared to the application of fertilizer alone

Implications of the presence of yeasts in tracheobronchial secretions of critically ill intubated patients

The presence of some microorganisms in the respiratory tract is a known risk factor for the infection of air passages; however, it is not clear whether this holds true for Candida spp. Thus, our objective was to determine the frequency of yeast colonization in the tracheobronchial secretions of critically ill intubated patients and to assess the presence of these yeasts in the infra-cuff region of the endotracheal tube (ET). Patients aged 18 years or older who had been using an endotracheal tube for 48 hours were recruited. Tracheal secretions were collected; after extubation, the ETs were cut into two fragments in the infra-cuff region. One of these fragments was placed in a solution containing antibiotics and sent to the lab for cultu re and identification of yeasts. The remaining fragment was fixed and subjected to scanning electron microscopy (SEM). In total, 20 patients with an average age of 73.3 years (± 13.1) participated in this study. These patients remained under endotracheal intubation and invasive mechanical ventilation for an average of 6. 4 (± 1.8) and 13.5 days (± 15), respectively. Of these patients, 45 % showed respiratory tract colonization by yeasts of the Candida genus, with C. albicans being the most frequently isolated species (66.7 %). Moreover, in almost 90 % of these patients, blastoconidia of the same yeast were found in the infra-cuff portion of the ET, as evidenced by SEM, strongly fixed on the ET surface. Yeasts isolated from both the infra-cuff region and the tracheobronchial secretions were susceptible to amphotericin B and fluconazole. In conclusion, our results show that the frequency of colonization by yeasts of the Candida genus in the tracheobronchial secretions of intubated patients within 48 hours is high, and that these species can also be found as a biofilm on the ET surface

Culture Strategies for Isolation of Fastidious Leptospira Serovar Hardjo and Molecular Differentiation of Genotypes Hardjobovis and Hardjoprajitno

The Leptospira serovar Hedjo belongs to the serogroup sejroe and this serovar is the most prevalent in bovine herds worldwide. The sejroe serogroup is the most frequently detected by serology in Brazilian cattle herds suggesting that it is due serovar Hardjo. In the molecular classification, this serovar has two genotypes: Hardjobovis and Hardjoprajitno. This serovar is as considered as fastidious pathogens, and their isolation is one of the bottlenecks in leptospirosis laboratories. In addition, its molecular characterization using genomic approaches is oftentimes not simple and time-consuming. This study describes a method for isolating the two genotypes of serovar Hardjo using culture medium formulations and suggests a get-at-able molecular characterization. Ten cows naturally infected which were seropositive were selected from small dairy farms, and their urine was collected for bacterial isolation. We evaluated three modifications of liquid Leptospira medium culture supplemented with sodium pyruvate, superoxide dismutase enzyme and fetal bovine serum, and the isolates were characterized by molecular techniques. After isolation and adaptation in standard culture medium, the strains were subcultured for 1 week in the three modified culture media for morphologic evaluation using electronic microscopy. Strains were molecularly identified by multilocus variable-number tandem-repeat analysis (MLVA), partial sequencing and phylogenic analyses of gene sec Y. Combining the liquid culture medium formulations allowed growth of the Leptospira serovar Hardjo in three tubes. Two isolates were identified as genotype Hardjobovis, and the other as genotype Hardjoprajitno. Morphologically, compared with control media, cells in the medium supplemented with the superoxide dismutase enzyme were more elongated and showed many cells in division. The cells in the medium supplemented with fetal bovine serum were fewer and lost their spirochete morphology. This indicated that the additional supplementation with fetal bovine serum assisted in the initial growth and maintenance of the viable leptospires and the superoxide dismutase enzyme allowed them to adapt to the medium. These culture strategies allowed for the isolation and convenient molecular characterization of two genotypes of serovar Hardjo, creating new insight into the seroepidemiology of leptospirosis and its specific genotypes. It also provides new information for the immunoprophylaxis of bovine leptospirosis

Control of bacterial stem rot on tomato by extracellular bioactive compounds produced by Pseudomonas aeruginosa LV strain

This study evaluated the antibiotic activity and induction of resistance in plants by compounds produced by Pseudomonas aeruginosa LV strain on the control of bacterial stem rot in tomato. Compounds were extracted from the cell-free supernatant of a bacterial culture and purified. The F4A fraction was composed of two major compounds, an antibiotic and a phenazine (PCN). The first experiment evaluated the antibiotic activity of F4A, and the second one compared the ability of F4A and PCN to elicit systemic acquired resistance (SAR). In both experiments, plants were infected with Pectobacterium carotovorum subsp. carotovorum (Pcc). The minimum inhibitory concentration of F4A was 7.81 μg mL−1, and PCN did not inhibit bacterial growth. The results suggest that F4A has antibiotic activity. Scanning electron microscopy revealed changes in bacterial cells after 3 h treatment with F4A. F4A and PCN decreased symptoms of stem rot and increased fruit production. Plant response was estimated by determination of peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase activity. Plants treated with PCN or F4A showed greater enzyme activity than plants that were not treated or treated with Bion®, suggesting that PCN increased SAR. The compounds showed the potential to control Pcc in vitro and in vivo and to induce plant response