BOD Chamber Research Articles

Characterization of Bipolaris bicolor germination: effects of a physical factor on fungal adaptability.

Studies on physiological responses to stimuli from physical factors are essential for understanding the dynamics of the microorganisms and higly important for the management of plant diseases. Besides, the development of an epidemiological model for pathogen populations requires studying their physiological responses to physical stimuli. The objective of this study was to evaluate the germination dynamics of spores from six isolates of Bipolaris bicolor under effects of light at 25°C. Suspensions of 1.6 × 105 conidia mL- 1 from the B. bicolor isolates were inoculated onto Petri dishes containing agar-water culture medium and incubated in a BOD chamber under two physical conditions: (a) constant darkness and (b) constant light for five hours. The study was conducted in a completely randomized design, with a 6 × 2 factorial arrangement (six B. bicolor isolates and two physical conditions) and five replications. The length of the germ tube was measured hourly. The constant darkness resulted in higher mean germ tube growth for the pathogen; however, differences in the final germination percentage were found among the isolates. The isolate F-24-02 exhibited the highest germination adaptability to constant darkness, presenting the longest germ tube length.

USE OF UNICONAZOLE IN GROWTH REGULATION AND BIOCHEMICAL CHANGES IN MAIZE

The current paper evaluated the incubation time, and doses of Uniconazole (UCZ) applied to maize seeds to verify the plants’ response at different phenological stages. MSG1001 hybrid seeds were treated with UCZ (0, 50, and 100 mg.kg-1 of seed) with different incubation times (IT – 1 min and 12 h). In the lab experiment, the treated seeds were displaced in rolls of the previously moistened Germitest paper and incubated for a week in a BOD chamber at 25ºC with a 12-hour photoperiod. In the greenhouse experiments, sowing was carried out in pots with sand, and supplementary irrigation was applied for ten days. In the field experiment, sowing was performed with 0.5 m spacing between rows in densities of 75,000 and 65,000 plants.ha-1. In the BOD and the greenhouse, the design of both experiments was entirely randomized in a double-factor scheme (IT x UCZ). A randomized block design in a triple-factor scheme (IT x UCZ x Population) was used in the field experiment. Seed treatment with UCZ did not promote germination inhibition. The concentration of 100 mg UCZ kg-1 of seed in the 12-hour IT resulted in a more significant accumulation of root mass in seedlings after one week in the BOD. In the greenhouse, plants in the V1 stage presented longer shoot lengths for the treatments that received UCZ. Incubation time influenced root length, and IT = 12 h at a concentration of 50 mg UCZ kg-1 of seed was more efficient than IT = 1 min. Application of 100 mg UCZ kg-1 of seed was more effective for accumulating chlorophylls A and B in IT = 1 min. In the field, seeds treated with UCZ changed plants for female flowering and the number of green leaves below the ear. The population of 75,000 plants.ha-1 was more productive, with UCZ contributing to the hybrid’s yield. Incubation of the seeds with 50 or 100 mg UCZ kg-1 of seed in IT = 1 min contributed to more productivity than IT = 12 h. The grains’ starch content increased with the application of UCZ at a dose of 100 mg kg-1 of seed, and the starch percentage was modified according to population density and incubation time.

Temperature increase impairs recognition among nestmates in the social wasp Polybia paulista H. von Ihering, 1896 (Vespidae: Polistinae: Epiponini)

Cuticular hydrocarbons (CHCs) of most terrestrial arthropods primarily serve as a protective barrier against desiccation and infection. Throughout evolution, these compounds have acquired another fundamental function: the exchange of signals during interactions between nestmates. However, even though cuticular hydrocarbons perform a dual function in social insects, little is known about the effect(s) of one function on the other in social insects, and no study has evaluated this relationship in social wasps. Therefore, the present study tests the hypothesis that the level of aggressiveness presented during induced encounters between nestmates of Polybia paulista who were subjected to different conditions temperature is different than between nestmates who remained under the same temperature conditions. If the hypothesis is confirmed, it is likely because the cuticle of the wasps that had been exposed to temperature variation adjusted to these conditions leading them not to recognize the cuticular chemical signature of their colony. To test this hypothesis, workers were exposed to temperature variation in a BOD chamber and then subjected to encounters with workers who were maintained at a constant temperature of 24℃. We also used control groups to evaluate the effect of isolation alone among the groups. According to our results, our hypothesis was confirmed, the level of aggressiveness presented between nestmates who were exposed to temperature variation and those who remained at 24℃ was significantly higher than the levels of aggressiveness presented between nestmates who remained isolated but under constant temperature during the same period, in some cases, it was similar to the aggressiveness presented in encounters between wasps from different colonies. During these encounters, wasps performed alarm behavior, bites, and stings not seen during encounters between wasps that remained under the same temperature, but in isolated groups. The lack of aggressive behavior under isolated conditions indicates that isolation had no effect on chemical recognition signature. These results suggest that temperature variation may have caused some change in the cues that allow recognition between nestmates. On the other hand, these results were not caused by isolation or stress generated by the study design and difference in the CHC profile of workers, as described in the literature, is consistent with our results.

Seed germination of Hesperozygis ringens (Benth.) Epling, an endemic and threatened species

Hesperozygis ringens (Lamiaceae), popularly known as espanta-pulga, is a threatened species endemic to rocky and sandy regions of the Pampa biome. One factor that can influence the low number of individuals of a species is a low seed germination rate influenced by temperature and/or light. Thus, the objective of this study was to evaluate the influence of light and temperature on the seed germination of H. ringens. The seeds of two lots were sown on a paper substrate and maintained in BOD chambers at temperatures of 15, 20, 25 and 30ºC in the presence and absence of light. The germination speed rate was evaluated every 3 days for 21 days. The experiment was completely randomized with treatments that had a 4 x 2 factorial design. The first visible sign (protrusion of the primary root) of germination was observed seven days after sowing. Germination occurred both in the presence and absence of light and the lowest temperatures significantly influenced the germination process and germination speed. For germinating the species, 15°C was the most favorable temperature compared to 20, 25 and 30°C. It can be concluded that a temperature of 15ºC favors the germination process of H. ringens seeds, which are insensitive to light.

New field technique to evaluate the action of the fungus Metarhizium anisopliae on Rhipicephalus (Boophilus) microplus tick

The tick Rhipicephalus microplus parasitizes cattle and transmits infectious agents, thus generating losses estimated at US$ 3.24 billion per year. Although chemical treatment is the main means of control, there are records of populations resistant to these products in several regions of Brazil. The losses associated with production animals and resistance to acaricides have given rise to searching for alternative control strategies. The entomopathogenic fungus Metarhizium anisopliae is a promising biological control agent. The objective of this work was to evaluate the action of the fungus M. anisopliae for controlling R. microplus, using a novel semi-field test protocol. The experiment began with application of a solution of M. anisopliae (isolate IBCB 425) at a concentration of 2 × 1013 conidia/hectare, to the soil. The broth containing the fungus was made up of water and mineral oil in the proportions of 19:1. The same broth was applied without addition of fungus in the control group. Females of R. microplus were placed on the soil, wrapped in voile fabric, in both plots. The groups were left in the pasture for 15 days, after which they were collected and kept in a BOD chamber for the end of incubation and hatching. Identical deposition was repeated three times every 14 days for both groups in the same areas. Engorged females of both groups were evaluated in relation to fungal infection, in histological sections that were then stained with hematoxylin and eosin (HE) and by means of in situ hybridization with oligonucleotides labeled with biotin. The results showed that the effectiveness of the fungus continued even beyond 30 days after application. This suggested that the colonization of the pasture by the fungus was stable. HE staining and in situ hybridization showed, respectively, changes to the reproductive system of the females and confirmation of infection by the species M. anisopliae. Based on these results, it is possible to demonstrate the action of this entomopathogen on the tick and suggested that the field markers technique can be used and replicated to evaluate the action of the fungus M. anisoplie in females of R. microplus.

Comparative seed germination, morphology and post-seminal development of two Bromeliaceae species with ornamental potential

Knowledge about the behavior of seeds is important to support studies to minimize the effects of predatory extractivism on ornamental bromeliads. The aim of this study was to evaluate the germination, seed morphology and post-seminal development of Hohenbergia belemii and Neoregelia compacta (Bromeliaceae) in different substrates. Seeds were disinfested with a sodium hypochlorite solution and germinated in four substrates: germitest paper; washed sand; vermiculite; and the commercial substrate Plantmax®. The experimental design was completely randomized in a 2 x 4 factorial scheme, with four repetitions and 50 seeds per repetition. The seeds were sown on the substrates and stored in plastic Gerbox® boxes, which were kept in BOD chambers with 12 hours photoperiod at constant temperature of 30ºC. Data were collected daily to calculate germination percentage and growth performance. The germination started on the 4th day after sowing (DAS) for H. belemii, with stabilization on the 11th DAS, while this occurred from the 5th DAS for N. compacta with stabilization on the 21st DAS. Germination was classified as development of epigeal and cryptocotylar seedlings for both species. The vermiculite substrate had a significant effect on seed germination, GSI (germination speed index) and growth of seedlings of both species. Our findings can support future research on seed technology and also contribute to better knowledge of the evolution of morphological characters of these bromeliad species.

Fabrication of PVA-Silver nanoparticle composite film for elimination of microbial contaminant from effluent

The effluent contains many harmful microbes which should be eliminated before it is discharged into a water body. Silver nanoparticles (AgNPs) being high-quality significance and have a great impact on this research field as it inhibits microbial proliferation and infection. Therefore, it may use for Bioremediation purposes, our laboratory is fascinated by the production of polymer matrix entrapment silver nanoparticles for in situ bio-remediation purposes. The AgNPs was prepared from sawdust by decoction method. The yellowish solution turns into dark brown colour indicating the formation of AgNPs. A sharp SPR (Surface Plasmon Resonance) band formation in UV-vis spectroscopy scan establishes the formation and stability of silver nanoparticles in an aqueous solution. SEM microphotograph indicated roughly spheroidal structure with (63±3) nm average diameters of newly synthesized AgNp. Polyvinyl alcohol (PVA) is eco-friendly and non-toxic to the environment was chosen for the preparation of polymeric matrix. The non-toxic concentration (1 μg/mL) of AgNp was dispersed into PVA solution followed by cross-linked with maleic acid. PVA- maleic acid is cross-linked by the formation of an ester bond, whereas silver nanoparticles physically entrap into the cross-linked matrix. The silver nanoparticles were released from the matrix nearly after 10 min of swelling of the composite film. In a microbial assay using E. coli agar medium, PVA-AgNp composite film shows the significant killing of microorganisms. Microbial elimination is measured indirectly by pH measurement and dissolved oxygen concentration measurement of the effluent in situ against RO- water, taken as control. The dissolved oxygen concentration from RO water and effluent water was measured on Day “0” followed by treatment and incubation at the BOD chamber. The treatment with PVA-AgNp composite film reduced the BOD Level and increase dissolved oxygen level simultaneously increasing the quality of water.

Daylight LED promotes photochemical ring contraction of 2-amine-4H-pyran-3-carbonitriles with consequent loss of their antifungal activity.

The initial objective of our work was to synthesize a series of 2-amino-4H-pyran-3-carbonitriles to be tested for their antifungal activities against economically relevant phytopathogenic fungi. Fourteen compounds were prepared in up to 94% yield and shown percentages of Botrytis cinerea inhibition above 70%. Despite the promising biological results, we observed that stock solutions prepared for biological tests showed color changing when kept for a few days on the laboratory bench, under room conditions, illuminated by common LED daylight tubes (4500-6000k). This prompted us to investigate the possible photo-induced degradation of our compounds. FT-IR ATR experiments evidenced variations in the expected bands for functional of -amino-4H-pyran-3-carbonitriles stored under LED daylight. Following, HPLC-UV analysis showed reductions in the intensity of chromatographic peaks of 2-amino-4H-pyran-3-carbonitriles, and but not for solutions kept in the dark. A solution of (E)-2-amino-8-(4-nitrobenzylidene)-4-(4-nitrophenyl)-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile underwent 84.4% of conversion after 72h of exposure to continuous LED daylight in a BOD chamber, and the reaction product was isolated in 36% yield and characterized as (E)-7-cyano-5-(4-nitrobenzylidene)-8-(4-nitrophenyl)bicyclo[4.2.0]oct-1(6)-ene-7-carboxamide (7*). Despite freshly prepared solutions of 2-amino-4H-pyran-3-carbonitriles produced antifungal activities, these solutions lost biological activity when left on the bench for a week. Besides, compound 7* formed from photo-induced degradation of 7 also showed no antifungal activity. With this, we hope to bring two contributions: (1) production of cyclobutenes through photochemical reactions of 2-amino-4H-pyran-3-carbonitriles can be carried out through exposure to simple white LED daylight; (2) biological applications of such 2-amino-4H-pyran-3-carbonitriles may be impaired by their poor photostability.

Thermal dependence in seed germination of Diospyros inconstans Jacq. (Ebenaceae)

Defining the cardinal temperatures for germination in the scenario of climate change with prediction of an increased terrestrial temperature plays an important role in conserving plant resources. This study aimed to define the cardinal temperatures, the time of conducting germination tests, and to apply the thermal time model for seeds of Diospyros inconstans. Thermal screening was carried out, based on germination tests performed in BOD chambers, at constant temperatures of 10, 20, 25, 30 and 40 °C, under a photoperiod of 12 hours/light. The cardinal temperatures for germination of D. inconstans seeds are 26.7 °C (optimal temperature), 13.8 °C (minimum temperature) and 37.7 °C (maximum temperature). Germination tests for the species can be conducted at optimum temperature, lasting 26 days for radicle emission and 63 days for formation of normal seedlings.

Storage of Simarouba amara Aubl. seeds

Prior knowledge about the physiological behavior of seeds under storage conditions allows the use of appropriate techniques to maintain viability. The goal of the present study was to classify the behavior of Simarouba amara seeds regarding their physiological potential during storage. The seeds were obtained from mature fruits, collected from five parent plants located at the Joanes-Ipitanga Environmental Protection Area (EPA) (Simões Filho, Bahia) in January 2018. Two experiments were carried out in a completely randomized design. In the first one, seed desiccation tolerance was evaluated with seven moisture contents: 5%, 7.5%, 10%, 12.5%, 15%, 25% and 35.6% (initial moisture). A germination test was carried out to evaluate the seeds’ vigor. In the second experiment, the seeds were stored with moisture contents of 7.5%, 12.5% and 35.6% at temperatures of 8 °C, 15 °C and 20 °C) for two storage periods, two and four months, and samples were taken to determine moisture content and conduct the germination test. Germination tests were performed in BOD chambers at 30 °C and with 12-hour light photoperiod. Daily counts were performed for the number of germinated seeds. We measured germination percentage, mean germination time, uncertainty index, percentage of normal seedlings, and percentage of unviable seeds. Simarouba amara seeds tolerate desiccation up to 7.5% moisture content, but lost viability when stored under this condition. At four months of storage all seeds lost viability. Simarouba amara seeds are recalcitrant and lose viability before reaching two months of storage.

Isotermas e calor isostérico de dessorção das sementes de tungue

<p><span class="fontstyle0">The tung is a species that has potential for biodiesel production, so for safe storage there is a need to get to know its hygroscopicity. The objective of this work was to determine the desorption isotherms based on the recommendation of a mathematical model, to define the safe moisture content for storage, and to obtain the isosteric heat for the tung seeds. In order to obtain the hygroscopic equilibrium water content, the static method was used, with 20g of seeds surrounded by a permeable tissue, and placed inside the desiccators containing salt solutions, in a BOD chamber with temperatures of 20, 25, At 30 and 35 ºC, water activity ranged from 0.14 to 0.812 decimal.The Akaike information criterion (AIC) and Bayesian Schwarz information criterion (BIC) were used to adjust the mathematical models and to help choose the best one. Among the tested models, ChungPfost was elected to represent the desorption isotherms of tung seeds. Integral isosteric desorption heat values in the equilibrium moisture content range from 2.08 to 8.35 (% b.s.) ranged from 3754 to 2555 kJ kg</span><span class="fontstyle0">-1</span> <br /><br /></p>

Viabilidade de sementes armazenadas de <i>Himatanthus sucuuba</i> Wood pelo teste de tetrazólio

Himatanthus sucuuba é uma espécie arbórea amazônica, de importância na medicina popular devido às suas propriedades terapêuticas. As estimativas da viabilidade de sementes dessa espécie ainda são escassas, tornando-se necessário o desenvolvimento de testes rápidos que permitam a avaliação da qualidade das sementes. O objetivo deste trabalho foi adequar a metodologia para a realização do teste de tetrazólio e verificar a viabilidade das sementes armazenadas de Himatanthus sucuuba comparando os resultados dos testes de germinação e tetrazólio. Para o precondicionamento, as sementes foram imersas em água destilada por períodos de 4, 8, 12 e 14 horas a 25°C. Posteriormente, foi realizada a coloração dos tecidos, pela imersão em solução de tetrazólio 0,025%, 0,075% e 0,100% por 90 minutos a 40°C no escuro, e para a avaliação as sementes foram distribuídas em seis classes. Paralelamente, foram conduzidos testes de germinação em câmara BOD a 30°C, estabelecendo-se critérios para avaliação da viabilidade e do vigor. O delineamento experimental foi o inteiramente casualizado, e a comparação de médias foi realizada pelo teste de Tukey a 5% de significância. O teste de tetrazólio na concentração de 0,075% a 40°C durante 90 minutos mostrou-se eficiente para avaliar a viabilidade e vigor das sementes de Himatanthus sucuuba. A comparação entre a germinação (78%) e o teste de tetrazólio (70%), não mostrou diferença significativa entre eles, concluindo-se que sementes armazenadas por 14 meses permaneceram viáveis.

Phytochemical investigation, phenol content and allelopathic potential of Croton heliotropiifolius Kunth extract

ABSTRACT: The present study involves phytochemical investigation, phenol content and allelopathic potential of Croton heliotropiifolius Kunth extract in the germination of Digitaria insularis (L.) Fedde. with extracts ethanolic and aqueous of C. heliotropiifolius leaf; was performed prospected secondary metabolites and Ultraviolet–visible (UV–visible) spectrophotometry tests for total phenols and flavonoids. The germination bioassay was performed in a BOD chamber (12L:12D) with plant extracts at 100, 50, 25 and 10%, with water as control against D. insularis seeds. The germination percentage (G%), germination speed index (IVG), abnormal seedlings (PAn%), root length and aerial part (CR and CPA) were evaluated. The extracts reduced the germination and development of the target species indicated by G% and IVG from the concentration of 10%. The same occurred with the variables PAn%, CR and CPA. In both extracts the presence of secondary metabolites was indicated, the phenol content obtained was 0.3422 mg EAG/g for the ethanolic extract and 0.375 mg EAG/g for the aqueous extract, for the flavonoids 0.1071 mg EQ/g in ethanolic extract and 0.0110 mg EQ/g in aqueous extract. The extracts demonstrated a reduction in germination and alteration in the physiology of Digitaria insularis (L.) Fedde seeds. KEYWORDS: Extracts, Secondary Metabolites, Germination.

Adequacy of electrical conductivity test for lentil seeds

The electrical conductivity test stands out among the existing physiological quality tests due to its simplicity of execution, repeatability, speed, easy interpretation of results, and low cost. This study aimed to establish a methodology for the test of electric conductivity in lentil seeds (Lens culinaris Medik), involving the seeds’ number of seeds and soaking time. The experiment was conducted at the Multidisciplinary Laboratory of the State University of Goiás, Campus Ipameri, in 2018. Lentil Silvina seeds were used, stored in the seed laboratory of the same institution. The experimental design used was completely randomized, in a 4x5 factorial scheme, with four seed lots (25, 50, 75, and 100 seeds) and five soaking times (3, 6, 9, 12, and 15 hours) at 25 ºC, with four replications. The initial seed quality was characterized (water content, first counting of germination, percentage of germination, accelerated aging and 1000-seed weight). For the electrical conductivity test, four repetitions of 25, 50, 75, and 100 seeds each were used, weighed on a digital scale with an accuracy of 0.001 g and placed in plastic cups, with a capacity of 200 mL, containing 75 mL of distilled water. Then, the plastic cups remained in a BOD chamber, adjusted at 25 °C and the measuring was performed after 3, 6, 9, 12, and 15 hours of soaking in a conductivity meter (DIGIMED DM 31), the results being expressed in μS cm-1 g-1. There was a significant interaction when evaluating the number of seeds per repetition and the soaking time. The use of replicates with 50 seeds subjected to 12 h of soaking shows the best results for the lentil seeds' electrical conductivity test.

Biotechnology of biomass production in vitro of fungi isolated from Pinus

Fungi are organisms capable of synthesizing metabolites of industrial interest and the standardization of biomass production for the extraction of these compounds has biotechnological applications. The objective of this work was to optimize the in vitro cultivation process for fungi isolated from Pinus sp., standardizing the best conditions for the production of biomass, contributing to its large scale production. Therefore, the conditions of in vitro cultivation of the fungi Botrytis cinerea, Rhizoctonia sp. and Suillus sp., were evaluated based on the maximum production of dry biomass (PBS), varying temperature, medium and cultivation time. The fungi were grown in glass flasks with liquid culture media, in a BOD chamber, without mechanical stirring. Potato-dextrose broth - PD broth (PD), Czapek - CZ broth (CZ) and Malt Extract - EM broth (EM) were evaluated at temperatures ranging from 8 to 32 ºC and incubation times from 7 to 35 days. PD broth showed better results for fungi B.cinerea and Rhizoctonia sp., when compared to CZ and EM broths, in PBS, while Suillus sp. showed better development in EM broth. The best growth temperature based on PBS was 12 ºC and 16 ºC, with 28 and 35 days of cultivation.

Crescimento e desenvolvimento de língua-de-vaca

Broad-leaved dock is a perennial weed, which infests mainly pastures, annual crops and perennials in the Southern of Brazil. Because it is a perennial plant, control becomes more difficult due to regrowth. The objective of this study was to evaluate the growth and development characteristics of cow-tongue plants in a non-competitive environment. The objective of this work was to monitor phenology and to evaluate the growth and development characteristics of broad-leaved dock plants in the non-competitive environment. The experiment was conducted in a greenhouse, after the seeds germinated in the BOD chamber, the seedlings were transplanted to pots filled with Cambisol Haplic. Destructive analyzes were performed at 0, 33, 94, 124, 156, 186 and 215 days after transplanting (DAT). The plants were collected separating the aerial part of the root system and the inflorescence, each part of the plant was taken to the drying oven by forced circulation of air for later determination of the dry mass. It was observed that the broad-leaved dock plants present initial growth rather slow. The total dry mass distribution was 56.8% of the total accumulated in the root system, followed by inflorescence (31.6%) and shoot (11.6%). The average number of seeds produced was 3,406 (± 389) per plant.

Classification and quality of Acca sellowiana (O. Berg) Burret seeds as to tolerance to desiccation

The objective of this paper was to determine the physiological behavior and seed quality of five genotypes of Acca sellowiana regarding desiccation. Seeds were obtained from five plants of urban backyards in the cities of Dois Vizinhos - PR (A1, A2) and Vacaria - RS (A3, A4, A5). The experiment was conducted in a bifactor arrangement (5x3), with five genotypes and three levels of water content (28%, 15% and 5%), arranged into complete randomized block design, with four replicates of 50 seeds each. Seeds were germinated on absorbent paper soaked with water, being kept in BOD chamber under temperature of 25±3°C with photoperiod of 16 hours. Germination percentage, speed index and average time were assessed by counting seeds every two days for 50 days, starting from the moment of radicle emergence. No significant differences were observed for germination percentage and all genotypes surpassing 79% of germination. Desiccation of seeds had low influence on germination speed index and average time of germination, although genotype influence was verified due to genetic variability. Genotype A5 has seeds with superior quality from the others. Acca sellowiana seeds have orthodox behavior.

Influence of the functional traits of seeds on germination dynamics and morphofunctional pattern of the seedlings

Aiming to compare morphofunctional features related to dispersion and establishment of plants, this study evaluated seed biometry and biomass, as well as germination and emergence potential in eight plant species native to the Semideciduous Seasonal Forest. Biometric measurements and biomass of seeds were obtained with a caliper and a precision scale. Afterwards, they were subjected to a germination test in BOD chambers under constant temperature and 12 hours photoperiod, and sown in styrofoam trays containing organic substrate and sand, kept in full sunlight. Data from germination and emergence was subjected to cluster analysis, according to the functional morphotype of the seedling. Most species presented seeds with a rounded shape, uniform staining at the mature stage, varied coat consistency, two types of dispersal syndromes (anemochory and zoochory) and four morphofunctional patterns in developing seedlings (crypto-hypogeal-storers, crypto-epigeal-storers, phanero-epigeal-storers and phanero-epigeal-foliaceous). The species belonging to group I (Albizia niopoides, Cedrela fissilis, Pterogyne nitens and Randia ferox) have foliaceous photosynthetic cotyledons and group II (Cabralea canjerana, Eugenia pyriformis, Inga laurina and Poecilanthe parviflora) have a reserve cotyledon. Species of group I had higher means in the percentage and rate of germination, less variability and amplitude of days for seedlings emergence. On the other hand, species of group II showed higher mean values in seed biometry and biomass. Thus, seeds with foliaceous cotyledons have an optimized development because of luminosity, whereas seeds with reserve tend to have slower development, remaining at the seedling stage for a longer time.

Effect of abiotic stress on bioactive compound production in germinated brown rice

AbstractBackground and objectivesThe objective of this study was to evaluate the effect of germination and various abiotic stresses on the technological, nutritional, and sensorial characteristics of brown rice. The seeds were soaked at 40°C and 30% humidity. The soaked seeds were allowed to germinate at 30°C for 36 hr in BOD chamber. The soaked rice grains were subjected to stress conditions in the last 4 hr of germination using saline (SBR/S), low temperature (4°C) (SBR/C), or a combination of saline and low temperature (SBR/B) and, after, it was analyzed the effect of germination and those abiotic stresses on the technological, nutritional, and sensorial characteristics of brown rice by the color parameters, texture profile, γ‐aminobutyric acid content, protein, and starch digestibilities.FindingsThe sprouted grains (SBR) were darker than the brown rice. The germinated rice grains exposed to cold stress were more resistant to crushing and chewing compared to grains exposed to salinity stress and those exposed to both cold and salinity stresses. Germination enhanced the γ‐aminobutyric acid (GABA) content and starch digestibility. The GABA content increased further, whereas the protein digestibility decreased in the germinated grains upon exposure to abiotic stresses.ConclusionsThe best conditions for germination and alternative processes that can help them to intensify the nutritional value of germinated grains must be elucidated. The results of this study were satisfactory for the nutritional and technological parameters, and thus, exposure of germinated grains to abiotic stress can be an alternative method for enriched rice production.Significance and noveltyColor and texture parameters change with germination and vary according to abiotic stresses. For the same reason, the content of GABA is increased. Protein digestibility is reduced, differently about the starch digestibility.

Germination of chia seeds submitted to saline stress.

Salinity, of both soil and water, is one of the main causes of crop yield decline. Within this context, the objective of this study was to evaluate the influence of different salts on the germination of chia seeds. The experiment was conducted in a BOD chamber at a constant temperature of 20 °C and in the presence of light. The seeds were placed on paper soaked with aqueous solutions of calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl2), at the osmotic potentials zero, -0.10, -0.20, -0.30, and -0.40 MPa. The effect of the salinity was evaluated using a germination test, with counts on days 7 and 14 after sowing. Based on the results, chia seeds tolerate concentrations of NaCl to -0.4 MPa and KCl to -0.20 MPa. The salts CaCl2 and MgCl2 had a negative effect on the germination and vigor of the chia seeds for the osmotic potentials -0.30 MPa and -0.20 MPa, respectively.