The physiological quality of Vigna unguiculata L. seeds shows tolerance to salinity.

Salinity reduces feijão-caupi production, and the search for tolerant varieties becomes important within the agricultural context, as, in addition to being used in the field, they can be used in genetic improvement. The objective was to for a identify variety that is tolerant to salinity considering the physiological quality of seeds and seedling growth. A 2 × 4 factorial scheme was used, referring to the varieties Pingo-de-ouro and Coruja, and four electrical conductivities of water (0; 3.3; 6.6 and 9.9 dS m-1). The physiological quality of seeds and the growth of seedlings were analyzed, in addition to the cumulative germination. The Pingo-de-ouro variety showed no germination, length of the shoot and root, dry mass of the shoot and root compromised up to electrical conductivity of 6 dS m-1 in relation to 0.0 dS m-1. On the other hand, the Coruja variety showed reduced germination, increased shoot and root length. The creole variety Pingo-de-ouro proved to be tolerant to salinity.

Sugarcane productivity and economic viability in response to planting density.

Planting with higher density in sugarcane is one of the practices used to overcome low productivity. However, this planting material is equivalent to 25% of the total cost of production, being one of the main expenses for cultivation. In this sense, the present work aims to evaluate the productivity and economic viability of sugarcane as a function of planting density. The experiment was carried out at Usina Monte Alegre in the municipality of Mamanguape, Paraíba, Brazil, from March 2021 to January 2022 with the variety RB92579. Seven planting density were studied: T1: 7 gems m-1, T2: 10 gems m-1, T3: 12 gems m-1, T4: 11 gems m-1, T5: 15 gems m-1, T6: 17 gems m-1, T7: 24 gems m-1, in randomized blocks with four replications. Growth, productivity and economic viability were evaluated. The highest productivity of cane and sugar, 77.69 ton ha-1 and 10.390 ton ha-1, respectively, was with planting density of 17 and 24 gems-1. While the minimum productivity of cane (61.313 ton ha-1) and sugar (7.924 ton ha-1) was recorded at sowing density of 7 and 11 gems-1. However, cultivation density with 7 and 10 gems m-1 were the ones that provided the highest profitability around 50%, followed by density of 12, 15 and 17 gems m-1 with an average of 45% profit and 11 and 24 gems m-1 with the lowest proportion of profit on average 38%. The cultivation with 17 gems m-1 of cane provides in cane-plant, variety RB92579, greater productivity with a profit rate of 45%, being the most suitable.

Influence of essential oils on the quality of Vigna unguiculata L. (Walp.) seeds compared by traditional method, image and multivariate analysis.

The extracts of medicinal plants are used for the treatment of seeds in order to reduce the action of phytopathogens and increase the vigor of the seeds. Currently, computerized image analysis has been used to assess the physiological quality of seed lots. The objective was to evaluate the efficiency of the Vigor-S® software in the evaluation of the physiological quality of cowpea seeds treated with essential oils, comparing with a traditional test and the principal component analysis. Two cowpea cultivars were analyzed, BRS Tumucumaque and BRS Guariba, treated with doses of natural extracts of Alfavaca, garlic, horsetail, citronella and pyroligneous acid. The traditional method consisted of evaluations for germination, first germination count, seedling emergence, emergence speed index, accelerated aging, fresh matter and dry matter of seedling and the image analysis for: seedling length, growth index, uniformity index, vigor index, and germination. A Principal component analysis was applied to reduce the number of variables. Horsetail, Alfavaca and citronella extracts were efficient in increasing the physiological quality of the seeds of at least one cultivar. The Vigor-S® software proved to be efficient compared to traditional tests to assess the physiological quality of seeds. Principal Component Analysis is an ally to identify the best extracts and doses to be used. The image analysis method proved to be effective when compared to the traditional method and can therefore be used.

Salicylic acid concentrations and forms of application mitigate water stress in sour passion fruit seedlings.

The present study aimed to evaluate concentrations and forms of application of salicylic acid used for water stress mitigation on the gas exchange and growth of yellow passion fruit. The experimental design was arranged in randomized blocks in a 4 × 4 × 2 factorial scheme, with four concentrations of salicylic acid (SA) via foliar application (0.0, 0.7, 1.4, and 2.1 mM), four SA concentrations via fertigation (0.0, 0.7, 1.4, and 2.1 mM), and two irrigation depths estimated based on the actual evapotranspiration - ETr (50 and 100% of ETr), with three replications. Water stress negatively affected the physiology and growth of yellow passion fruit seedlings at 75 days after sowing (DAS). The application of salicylic acid, regardless of the form of application, attenuates the effects of water stress on gas exchange and growth of yellow passion fruit, with the best results obtained when applying a concentration of 1.30 mM via leaf or 0.90 mM via fertirrigation. The combination of foliar application of AS and fertigation contributed to improve photosynthetic and growth parameters under water conditions of 50 and 100% of ETr. The foliar application of AS presents superior responses to the application via fertigation. These results reinforce the hypothesis that the attenuation of water stress by salicylic acid is related to the maintenance of gas exchange, which depends on the concentration and form of application, and studies testing combinations throughout the crop cycle become promising for advances in knowledge from the action of this phytohormone on abiotic stress.

Methods of application of salicylic acid as attenuator of salt stress in cherry tomato.

Salt stress caused by excess salts present in irrigation water, is one of the biggest barriers in agricultural production, especially in semi-arid regions. Thus, the use of substances, such as salicylic acid, that minimize the deleterious effects of salinity on plants can be an alternative to ensure satisfactory production. In this context, the objective of this study was to evaluate the effects of different methods of application of salicylic acid on the growth, production and water use efficiency of cherry tomato plants under salt stress. The study was conducted in a greenhouse, using an Entisol soil with a sandy loam texture. The treatments were distributed in a completely randomized design, in a 2×4 factorial arrangement, corresponding to two levels of electrical conductivity of irrigation water - ECw (0.6 and 2.6 dS m-1) and four methods of application of salicylic acid (Control - without application of SA; via spraying; via irrigation and via spraying and irrigation), with five replicates and one plant per plot. The salicylic acid concentration used in the different methods was 1.0 mM. Application of salicylic acid via foliar spraying increased the growth, production and water use efficiency of cherry tomato plants. The salt stress induced by the electrical conductivity of 2.6 dS m-1 was attenuated by the foliar application of salicylic acid. The use of water of 2.6 dS m-1 associated with the application of salicylic acid via irrigation water further intensified the adverse effects of salinity on cherry tomato plants.

Xylella fastidiosa subsp. pauca and fastidiosa Colonize Arabidopsis Systemically and Induce Anthocyanin Accumulation in Infected Leaves.

The bacterium Xylella fastidiosa is a multihost pathogen that affects perennial crops such as grapevine, sweet orange, and olive tree worldwide. It is inherently difficult to study these pathosystems owing to the long-term growth habit of the host plant. Thus, the availability of model plants becomes essential to accelerate discoveries with economic impact. In this study, we uncovered evidence that the model plant Arabidopsis thaliana can be colonized by two different X. fastidiosa subspecies, pauca and fastidiosa. We observed that these bacteria are able to move away from the inoculation point as high bacterial populations were found in distant tissues. In addition, confocal laser scanning microscopy analysis of bacterial movement inside the petiole revealed the ability of the bacterium to move against the net xylem flow during the time course of colonization forming biofilm. These findings provide evidence for the capacity of X. fastidiosa to colonize Arabidopsis. Furthermore, leaves inoculated with X. fastidiosa showed a significant accumulation of anthocyanin. We propose that the X. fastidiosa subsp. pauca or fastidiosa colonization pattern and anthocyanin accumulation in the Arabidopsis ecotype Col-0 can be used as marker phenotypes to facilitate further studies aimed at improving genetic components involved in X. fastidiosa-host interaction.

Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence.

Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants.

Risk factors associated with selected indicators of milk quality in semiarid northeastern Brazil.

The aim of this study was to gain information on quality traits, mainly bacterial and somatic cell counts of bulk milk, produced by small- and medium-scale producers in a semiarid northeastern region of Brazil and to identify and characterize possible risk factors associated with those quality traits. A cross-sectional study was performed on 50 farms. Bulk milk samples were collected for bacterial and somatic cell counts. Additionally, information about farm demographics, general management practices, hygiene, and milking procedures was also obtained. Multivariable analysis using logistic regression was performed with predictors previously identified by univariate analysis using a Fisher's Exact test. Aerobic mesophilic bacteria counts varied from 3.59 log to 6.95 log cfu/mL, with geometric mean of 5.27 log cfu/mL. Mean total coliform count was 3.27 log (1.52 log to 5.89 log) most probable number (MPN)/mL, whereas mean thermotolerant coliforms was 2.38 log (1.48 log to 4.75 log) MPN/mL. A high positive correlation was observed between aerobic mesophilic bacteria and coliform counts. Although most farms met the standard for the current regulations for total bacteria (88%) and somatic cell counts (94%), nearly half of the producers (46%) would have problems in achieving the 2012 threshold limit for total bacteria count if no improvement in milk quality occurs. Mean value for staphylococci was 3.99 log (2.31 log to 6.24 log) cfu/mL, and Staphylococcus aureus was detected in 33 (66%) farms. Premilking teat-end wash procedure (odds ratio=0.191) and postmilking teat dip (odds ratio=0.67) were associated with lower aerobic mesophilic bacteria and Staphylococcus aureus counts in bulk milk, respectively. Considering that the farm characteristics in this study are representative of the semiarid northeastern region, these findings encourage further investigations for supporting intervention measures intended to improve the quality of milk produced by smallholders.

Caracterização dos taninos condensados das espécies maniçoba (Manihot pseudoglazovii), flor-de-seda (Calotropis procera), feijão-bravo (Capparis flexuosa, L) e jureminha (Desmanthus virgatus) / Characterization of condensed tannin of the species maniçoba (Manihot pseudoglaziovii), flor-de-seda (Calotropis procera), feijão-bravo (Capparis flexuosa) and jureminha (Desmanthus virgatus)

Caracterizaram-se os taninos condensados (TC) e determinaram-se a composição bromatológica e a digestibilidade in vitro da matéria seca (DIVMS) das espécies maniçoba (Manihot pseudoglazovii Pax & Hoffman), flor-de-seda (Calotropis procera), feijão-bravo (Capparis flexuosa, L) e jureminha (Desmanthus virgatus (L.) Willd). As concentrações em tanino solúvel, tanino ligado ao resíduo e tanino total (TT) das espécies foram determinadas pelo método butanol-HCL e a adstringência pelo método de difusão radial. Para a DIVMS, foi utilizado método de dois estágios. Foram observadas diferenças entre as espécies (P<0,01) quanto à concentração e adstringência dos taninos. As maiores concentrações foram encontradas na jureminha, 2,4 por cento TT e 13,7-3 de adstringência. Não foi detectado tanino na flor-de-seda. O teor em PB foi acima de 16 por cento em todas as espécies estudadas, e o FDA e lignina abaixo de 39 e 15 por cento, respectivamente. A DIVMS foi baixa na jureminha, 43 por cento, e alta na flor-de-seda, 80 por cento. A correlação entre a DIVMS e a concentração em taninos condensados foi baixa (r=0,097)

Condensed tannins (CT) of the species maniçoba (Manihot pseudoglaziovii), flor-de-seda (Calotropis procera), feijão-bravo (Capparis flexuosa) and jureminha (Desmanthus virgatus) were characterized and the chemical composition and in vitro dry matter digestibility (IVDMD) of those species were determined. Concentration of soluble tannin (ST), bound tannin (BT) and total tannin (TT) of the plants was determined using butanol-HCL method; astringency was determined, using radial diffusion method, and the IVDMD was determined using two-stages method. Concentration and astringency of condensed tannins varied between species (P<0.01). Jureminha was the species that presented the highest value (2.4 percent TT and 13.7-3 astringency). No tannins were detected in flor-de-seda. Crude protein was higher than 16 percent in all studied species, and the ADF and lignin values were lower than 39 and 15 percent, respectively. The IVDMD was low in jureminha (43 percent) and high in flor-de-seda (80 percent). The correlation between IVDMD and TT was low (r²=0.097)

Microbial hydroxylation of quinoline in contaminated groundwater: evidence for incorporation of the oxygen atom of water.

Studies conducted in an aquifer contaminated by creosote suggest that quinoline is converted to 2(1H)quinolinone by an indigenous consortium of microorganisms. Laboratory microbial experiments using H218O indicate that water is the source of the oxygen atom for this hydroxylation reaction under aerobic and anaerobic conditions.

Metabolic studies of transient tyrosinemia in premature infants.

The recently developed technique of gas chromatography-mass spectrometry supported by computer has considerably improved the analysis of physiologic fluids. This study attempted to demonstrate the value of this system in the investigation of metabolite patterns in urine in two metabolic problems of prematurity, transient tyrosinemia and late metabolic acidosis. Serial 24-hr urine specimens were analyzed in 9 infants. Transient tyrosinemia, characterized by 5-10-fold increases over basal excretion of tyrosine, p-hydroxyphenyllactate, and p-hydroxyphenylpyruvate in urine, was noted in five of the infants. Several infants had fluctuating levels of tyrosine metabolites in urine although dietary protein intake remained constant at 3-4 g/kg/24 hr and ascorbic acid at 50 mg/24 hr. Late metabolic acidosis was seen in four infants, but bore no relation to transient tyrosinemia. The ratio of net acid to urea excretion in urine increased with increasing base deficit, implying a nonprotein origin of the metabolic acid. No unique metabolic patterns were characteristic of late metabolic acidosis.