Suitability of tetrazolium test for Tamarindus indica L. seeds

Seed quality is routinely assessed by direct tests, e.g, the germination test, or indirect tests like the tetrazolium test, which has shoown to be promising in the determine viability and vigor, allowing the diagnosis of the main problems that may affect seed quality, such as mechanic damages, field deterioration and storage. In this respect, this study was conducted to develop a tetrazolium test protocol to evaluate the viability and vigor of Tamarindus indica L. seeds. Before exposing the seeds to the tetrazolium solution, seed preconditioning studies were carried out in which seven soaking times were tested. The soaking time that did not cause damage to the seed embryo and allowed the removal of the seed coat to expose the seed structures to the tetrazolium salt was selected. Then, an experiment was set up in a completely randomized design with a 2x3x3 factorial arrangement involving two seed lots, three soaking times in tetrazolium salt (6, 12 and 16 h) and three salt concentrations (0.075, 0.1 and 0.5%), totaling 18 treatments with four replicates of 25 seeds, evaluated at 40 ºC. For each treatment, the seeds were divided into three classes, namely, viable and vigorous embryos (class 1); viable embryos (class 2) and non-viable or dead embryos (class 3). For a comparison with the tetrazolium test results, the two seed lots were analyzed for water content, germination, emergence, first count, germination speed index, emergence speed index, growth and seedling dry weight. The viability and vigor of T. indica seeds can be evaluated after a soaking period of 48 h and immersion for 6h in tetrazolium salt at the concentration of 0.1%, at 40°C, with provides results similar to conventional seed viability tests. The tetrazolium test proved to be adequate to differentiate T. indica seed lots in terms of viability.

Fungal and seed treatment interference in the viability of coriander seeds

ABSTRACT The determination of the sanitary quality is important to diagnose if the commercialized lots are free of pathogens and to make a decision about the need for seed treatment. The objective was to evaluate the interference of fungi associated with coriander seed lots in their physiological performance and the effect of seed treatment with the fungicide Metalaxyl-m + Fludioxonil. The study was carried out in two steps. In experiment I, the physiological potential and sanitary characterization of 18 coriander seed lots were evaluated, using the tests, water content, tetrazolium test and health test. In experiment II, we evaluated the physiological performance of coriander seeds with and without fungicide treatment using the first count and germination test. Coriander seed lots showed high physiological potential, however, not all lots expressed their maximum potential in the germination test without treatment, due to the negative effect of fungi associated with seeds, mainly A. dauci and in association with A. alternata. There was an improvement in the physiological performance of coriander seeds treated with Metalaxyl-m + Fludioxonil fungicide.

Quality of soybean seeds submitted to different treatments and storage conditions

Chemical seed treatment is a recommended technique to protect seeds from pathogens that can affect their quality. The objective of this work was to analyse the quality of soybean seeds with different treatments under different storage temperatures. Seeds of cultivar ‘M 8378 IPRO’ produced in Mato Grosso, Brazil were used. A completely randomised design was used in a 4 × 3 two-factorial scheme. The seeds were treated with three different combinations of chemicals (fungicides, insecticides, polymer and drying powder) in addition to the control (untreated seeds) combined with three different storage temperatures (13 °C, 19 °C and uncontrolled temperature), with three repetitions. Quality was assessed by the germination test (TG), accelerated aging (AA), field emergence (FE), tetrazolium test (TZ) and isoenzyme analysis. The uncontrolled storage temperature negatively influenced the variables germination, accelerated aging and field emergence. The vigour and viability of the tetrazolium test showed that untreated seeds had better physiological quality than seeds with chemical treatment. The expression of isoenzymes showed a difference between treatments. Even with the stress caused by the seed treatment, this tool is very important for the initial protection of the seedlings.

EVALUATION OF TWO METHODS OF GERMPLASM COLLECTION IN MEXICO SOUTHEAST

The implementation of good farming practices in seed collecting is fundamental key to guarantee the physiological and genetic quality of forest seeds. The objective of this work was to evaluate the implementation of two methods to collect seedsfrom Cedrelaodorata L.toguarantee seeds of high physiologicalquality. Seeds from 40 superior phenotypically trees of Cedrelaodorata L. in Yucatan Mexico peninsula region were collected from March to May 2019.The collect methods applied in this research werethe traditionalcollectand the climb trees. The physiological quality of seeds wasevaluated by germination and tetrazolium test. The laboratory analysis confirmed 88% of seeds pure with 94% of germination in climbing trees method, in contrast in the traditional method showed 66% of seeds pure with 72% of germination. The results by conventional germination it was not showed significative statistical differences. These results are part of novel contributions in collectmethodology using tools to climb on trees which to be complement of superior phenotypically trees selection, contribute comprehensively to obtain physiological and genetic quality forest seeds.

Methodology of the tetrazolium test for identifying viable seeds of orchids of the genus Cattleya native to the Brazilian Cerrado

Orchids need measures for conservation of their species, among them the creation of seed banks. This study analyzes suitable methodologies to identify the viability of Cattleya seeds through the tetrazolium test. Seeds of Cattleya nobilior Rchb. and Cattleya walkeriana Gardn. were submitted to three preconditioning: no soaking (control); sucrose (10%); or distilled water. After 24 hours, they were submitted to tetrazolium solution with three types of conditioning: oven (40 °C); water bath (40 °C); or room temperature. Subsequently, the percentage of viable seeds (VS) was calculated and in vitro sowing was carried out. Germination percentage (G) was determined after 45 days. A completely randomized design was used for each species studied, with treatments arranged in a 3x3 factorial scheme (three preconditioning and three conditioning), with eight replicates of one tube each. The experiment was performed in duplicate. The highest viability values found in the tetrazolium test were close to those of germination (C. nobilior: VS = 88% e G = 97%; C. walkeriana: VS = 88% e G = 95%) for Cattleya species native to the Cerrado. The conditioning at ambient temperature had a greater effect on seed visualization for both species studied, suggesting that the tetrazolium test should be performed at this conditioning temperature.

Prediction of Severe Attacks of Exercise-induced Bronchial Asthma in Children using Immunological Blood Parameters

Bronchial asthma is considered an umbrella diagnosis for various diseases with certain pathophysiological mechanisms (endotypes) and variable clinical manifestations (phenotypes). The phenotype of exercise-induced asthma is one of the most common variants of the disease in children and adolescents. The treatment tactic of acute asthma attack is unified and depends of the severity in contrast to preventive therapy the vector of which provides an individualized approach. However, the issues concerning the duration, frequency of administration and amount of drugs prescription not finally resolved. The purpose of the study was to evaluate the blood immunological parameters in patients with exercise-induced asthma phenotype to predict the severity of disease exacerbation and optimize the reliever therapy. Material and methods. We examined 43 children suffering from exercise-induced asthma. Two clinical groups were formed according to the severity of the exacerbation. The first group included 22 patients with moderate exacerbation of asthma, and the second group had 21 children with severe symptoms of the disease, which was interpreted as a severe asthma attack. There were not any significant differences by sex, place of residence, age and diseases duration among comparison groups. The obtained results showed a significant increase in the level of B-lymphocytes in patients of first clinical group (26.64 %) compared with children with severe exacerbation (20.40 %), increase content of T-lymphocytes (due to T-helper cells) in schoolchildren of the second clinical group (42.32 %) compared with patients with moderate asthma attack (33.32 %). The attributive risk of more severe disease exacerbation with B-lymphocytes ≤20 % and T- helper cells ≥20 % was 36.6 %, the relative risk was 1.9 with odds ratio 5.0. A significantly higher level of pharmazan-positive neutrophils in spontaneous and stimulated modifications of the nitro blue tetrazolium test was recorded in patients with moderate exacerbation (35.18 % and 45.09 %) compared with children of the second clinical group (19.33 % and 27.81 %). The content of neutrophils in the spontaneous nitro blue tetrazolium test ≤15 % allowed evaluating severe compared with moderate asthma attack with specificity of 95.5 %, positive predictive value of 90.9 %, and positive likelihood ratio 10.5. Conclusion. The use of certain immunological parameters allows working out an individual plan for asthma attacks and may reduce the frequency of severe exacerbations in children suffering from exercise-induced bronchial asthma

Methodological adjustments to the tetrazolium test in coriander seeds

The reduction in the time to perform the tetrazolium test is critical in decision making at pre and post-harvest of seeds. Thus, the objective of this study was to investigate different concentrations of the tetrazolium salt solution, temperatures, and staining times, to reduce the time for assessing the viability of coriander seeds by the tetrazolium test. The study was divided into two experiments conducted independently but sequentially. The seeds were evaluated for water content, germination, and viability in both experiments by the tetrazolium test. A completely randomized design was used, with four replications. For the tetrazolium test, the seeds were preconditioned by direct immersion in water for sixteen hours at 20 °C. In experiment I, the seeds were exposed to different concentrations of the tetrazolium salt solution (0.25; 0.5; 0.75; and 1.0%). In experiment II, different combinations of temperatures (35; 40; and 45 °C) and staining times (three, four, five, and six hours) were tested. Based on the findings, it was concluded that the best staining pattern of coriander seeds for performing the tetrazolium test is achieved by using the concentration of 0.5% tetrazolium salt solution for five hours at 40 °C.

Seed viability test of orchids native to the Brazilian Savanna1

ABSTRACT An essential factor for the formation of a native orchid seed bank is the identification of the viability of stored seeds. This study aimed to determine a methodology for optimizing the tetrazolium test, in the identification of the viability of stored seeds of two Orchidaceae medicinal species native to the Brazilian Savanna. Seeds of Miltonia flavescens Lindl. and Schomburgkia crispa Lindl. were submitted to three pre-conditioning conditions: no soaking (control), sucrose solution or distilled water. The seeds were then submitted to a tetrazolium solution, with three types of conditioning: oven, water bath or ambient temperature. The M. flavescens seeds showed a germination of 86.91 %, with a higher percentage of viable seeds (62.32 %) when submitted to pre-conditioning with sucrose + oven conditioning. For S. crispa, the germination was 97.78 %, with a higher percentage of viable seeds for the control treatment + ambient temperature (89.49 %). These results suggest that specific protocols should be used to conduct the tetrazolium test in Orchidaceae. Moreover, when performed on a sample basis, the tetrazolium test should only be used to indicate the seed viability.