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.(AU)

Inoculation of corn seeds with Azospirillum brasilense in different temperatures

Growth-promoting bacteria Azospirillum brasilense, used as an inoculant in corn culture, can be severely affected by the exposure temperature, with a lethal effect above 35°C, when cultivated alone under laboratory conditions. Such effects may limit the associative interaction between plant-bacteria, with reduced inoculation efficiency, resulting in a lower growth rate of the plant and an increase in oxidative stress. Thus, the objective of the research was to evaluate the efficiency of the inoculation process with A. brasilense in seeds and in the initial growth of seedlings of two corn cultivars submitted to different temperatures. Were utilized corn hybrids seed Syn 488 and Syn 505. The experimental design was completely randomized in a 2 x 4 factorial scheme (with and without inoculation of A. brasilense x 4 sowing temperatures: 20, 25, 30, and 35ºC), with four replications. The inoculation efficiency in corn seedlings submitted to different temperatures was evaluated through the following tests: germination, first count, seedling length and dry weight. In addition, responses at the biochemical level of the interaction (temperatures x inoculation) for the content of photosynthetic pigments and hydrogen peroxide (H2O2), antioxidant enzymes and lipid peroxidation were evaluated. The inoculation with A. brasilense changed the morphological and biochemical responses of corn seedlings, and the inoculation process was efficient for all temperatures tested. The best results were under temperatures 25, 30, and 35°C. Plant and bacteria when exposed to temperature conditions (30°C inoculated) showed a significant increase in plant biomass and activity of antioxidant enzymes.(AU)

Inoculation of corn seeds with Azospirillum brasilense in different temperatures / Inoculation of corn seeds with Azospirillum brasilense in different temperatures

Growth-promoting bacteria Azospirillum brasilense, used as an inoculant in corn culture, can be severely affected by the exposure temperature, with a lethal effect above 35°C, when cultivated alone under laboratory conditions. Such effects may limit the associative interaction between plant-bacteria, with reduced inoculation efficiency, resulting in a lower growth rate of the plant and an increase in oxidative stress. Thus, the objective of the research was to evaluate the efficiency of the inoculation process with A. brasilense in seeds and in the initial growth of seedlings of two corn cultivars submitted to different temperatures. Were utilized corn hybrids seed Syn 488 and Syn 505. The experimental design was completely randomized in a 2 x 4 factorial scheme (with and without inoculation of A. brasilense x 4 sowing temperatures: 20, 25, 30, and 35ºC), with four replications. The inoculation efficiency in corn seedlings submitted to different temperatures was evaluated through the following tests: germination, first count, seedling length and dry weight. In addition, responses at the biochemical level of the interaction (temperatures x inoculation) for the content of photosynthetic pigments and hydrogen peroxide (H2O2), antioxidant enzymes and lipid peroxidation were evaluated. The inoculation with A. brasilense changed the morphological and biochemical responses of corn see

Growth-promoting bacteria Azospirillum brasilense, used as an inoculant in corn culture, can be severely affected by the exposure temperature, with a lethal effect above 35°C, when cultivated alone under laboratory conditions. Such effects may limit the associative interaction between plant-bacteria, with reduced inoculation efficiency, resulting in a lower growth rate of the plant and an increase in oxidative stress. Thus, the objective of the research was to evaluate the efficiency of the inoculation process with A. brasilense in seeds and in the initial growth of seedlings of two corn cultivars submitted to different temperatures. Were utilized corn hybrids seed Syn 488 and Syn 505. The experimental design was completely randomized in a 2 x 4 factorial scheme (with and without inoculation of A. brasilense x 4 sowing temperatures: 20, 25, 30, and 35ºC), with four replications. The inoculation efficiency in corn seedlings submitted to different temperatures was evaluated through the following tests: germination, first count, seedling length and dry weight. In addition, responses at the biochemical level of the interaction (temperatures x inoculation) for the content of photosynthetic pigments and hydrogen peroxide (H2O2), antioxidant enzymes and lipid peroxidation were evaluated. The inoculation with A. brasilense changed the morphological and biochemical responses of corn see

Cadmium toxicity on seed germination and initial growth of chia

In recent years, there has been a growing concern related to soil and water contamination due to the constant dispersal of toxic metals. In addition to their ecotoxicological potential, these elements exhibit a cumulative character that favors their permanence in soil and passage to living organisms, which can lead to an ecological imbalance. Among toxic metals, cadmium (Cd) is an obstacle to agriculture because it can adversely affect food quality and human health, as well as diminish plant growth and productivity. Thus, the objective of this work was to evaluate the toxicity of cadmium on seed germination and initial growth of chia. The ecotoxicological effects of four Cd concentrations (15; 30; 45; and 60 mg L-1) were evaluated. The response variables were germination percentage, first count, germination speed index, total length, shoot length, root length, seedling dry mass, and tolerance index. It is concluded that the presence and accumulation of Cd in the culture substrate played an inhibitory role in seed germination and initial seedling growth of chia starting at 15 mg L-1. On the other hand, no significant effect was observed for the treatments in relation to dry mass of the chia seedlings.

Cadmium toxicity on seed germination and initial growth of chia

In recent years, there has been a growing concern related to soil and water contamination due to the constant dispersal of toxic metals. In addition to their ecotoxicological potential, these elements exhibit a cumulative character that favors their permanence in soil and passage to living organisms, which can lead to an ecological imbalance. Among toxic metals, cadmium (Cd) is an obstacle to agriculture because it can adversely affect food quality and human health, as well as diminish plant growth and productivity. Thus, the objective of this work was to evaluate the toxicity of cadmium on seed germination and initial growth of chia. The ecotoxicological effects of four Cd concentrations (15; 30; 45; and 60 mg L-1) were evaluated. The response variables were germination percentage, first count, germination speed index, total length, shoot length, root length, seedling dry mass, and tolerance index. It is concluded that the presence and accumulation of Cd in the culture substrate played an inhibitory role in seed germination and initial seedling growth of chia starting at 15 mg L-1. On the other hand, no significant effect was observed for the treatments in relation to dry mass of the chia seedlings.(AU)

Germination and vigor of linseed seeds under different conditions of light, temperature and water stress / Germinação e vigor de sementes de linhaça sob diferentes condições de luz, temperatura e estresse hídrico

Linseed (Linum usitatissimum L.), cultivated from seeds, is one of the oldest plants domesticated by humans and is popularly used as a medicine. It can be used as the raw material to produce oil and bran because it has high lipids content, fiber and proteins. Based on the economic potential of this species and the need for more information about its physiology, the goal of this study was to analyze the effects of light, temperature and water stress on the germination and vigor of linseed seeds. In experiment I the seeds were sown on paper at constant temperatures of 15, 20, 25 and 30 ºC in the presence and absence of light. In experiment II, the seeds were placed on paper germitest soaked in solutions of polyethylene glycol (PEG 6000) at osmotic potentials corresponding to zero, –0.10, –0.20, –0.30, –0.40, –0.50 and –0.60 MPa. To evaluate the physiological potential, the following tests were made: germination, first germination count, length and dry mass of seedlings, and water stress. It was found that the highest percentages of germination and vigor occurred at a constant temperature of 20 °C, both in the presence and absence of light. The reduction of the osmotic potential of the substrate promoted a significant decrease in the germination and vigor of the linseed seeds. Osmotic potentials equal or less than –0.30 MPa were harmful to germination and there was no normal seedling development starting at –0.50 MPa.

A linhaça (Linum usitatissimum L.), cultivada através de sementes, é uma das plantas mais antigas domesticadas pelo homem, utilizada popularmente como medicamento. Pode ser empregada como matéria-prima na produção de óleo e farelo por possuir alto teor de lipídios, fibras e proteínas. Diante do potencial econômico da espécie e da necessidade de informações sobre sua qualidade fisiológica, objetivou-se analisar o efeito da luz, temperatura e estresse hídrico na germinação e no vigor de sementes de linhaça. No experimento I, as sementes foram semeadas sobre papel nas temperaturas constantes de 15, 20, 25 e 30 ºC na presença e ausência de luz. No experimento II, as sementes foram colocadas sobre papel embebido em soluções de polietileno glicol (PEG 6000) nos potenciais osmóticos correspondentes a zero; –0,10; –0,20; –0,30; –0,40; –0,50; –0,60 MPa. Para avaliação do potencial fisiológico foram realizados os testes de: germinação, primeira contagem de germinação, comprimento e massa seca de plântulas e estresse hídrico. As maiores percentagens de germinação e vigor ocorreram quando da temperatura constante de 20 °C, tanto na presença quanto na ausência de luz. A redução do potencial osmótico do substrato causou decréscimo significativo na germinação e no vigor das sementes de linhaça. Potenciais osmóticos iguais ou inferiores a –0,30 MPa foram prejudiciais à germinação não havendo desenvolvimento de plântulas normais a partir de –0,50 Mpa.

Germination and vigor of linseed seeds under different conditions of light, temperature and water stress / Germinação e vigor de sementes de linhaça sob diferentes condições de luz, temperatura e estresse hídrico

Linseed (Linum usitatissimum L.), cultivated from seeds, is one of the oldest plants domesticated by humans and is popularly used as a medicine. It can be used as the raw material to produce oil and bran because it has high lipids content, fiber and proteins. Based on the economic potential of this species and the need for more information about its physiology, the goal of this study was to analyze the effects of light, temperature and water stress on the germination and vigor of linseed seeds. In experiment I the seeds were sown on paper at constant temperatures of 15, 20, 25 and 30 ºC in the presence and absence of light. In experiment II, the seeds were placed on paper germitest soaked in solutions of polyethylene glycol (PEG 6000) at osmotic potentials corresponding to zero, –0.10, –0.20, –0.30, –0.40, –0.50 and –0.60 MPa. To evaluate the physiological potential, the following tests were made: germination, first germination count, length and dry mass of seedlings, and water stress. It was found that the highest percentages of germination and vigor occurred at a constant temperature of 20 °C, both in the presence and absence of light. The reduction of the osmotic potential of the substrate promoted a significant decrease in the germination and vigor of the linseed seeds. Osmotic potentials equal or less than –0.30 MPa were harmful to germination and there was no normal seedling development starting at –0.50 MPa.(AU)

A linhaça (Linum usitatissimum L.), cultivada através de sementes, é uma das plantas mais antigas domesticadas pelo homem, utilizada popularmente como medicamento. Pode ser empregada como matéria-prima na produção de óleo e farelo por possuir alto teor de lipídios, fibras e proteínas. Diante do potencial econômico da espécie e da necessidade de informações sobre sua qualidade fisiológica, objetivou-se analisar o efeito da luz, temperatura e estresse hídrico na germinação e no vigor de sementes de linhaça. No experimento I, as sementes foram semeadas sobre papel nas temperaturas constantes de 15, 20, 25 e 30 ºC na presença e ausência de luz. No experimento II, as sementes foram colocadas sobre papel embebido em soluções de polietileno glicol (PEG 6000) nos potenciais osmóticos correspondentes a zero; –0,10; –0,20; –0,30; –0,40; –0,50; –0,60 MPa. Para avaliação do potencial fisiológico foram realizados os testes de: germinação, primeira contagem de germinação, comprimento e massa seca de plântulas e estresse hídrico. As maiores percentagens de germinação e vigor ocorreram quando da temperatura constante de 20 °C, tanto na presença quanto na ausência de luz. A redução do potencial osmótico do substrato causou decréscimo significativo na germinação e no vigor das sementes de linhaça. Potenciais osmóticos iguais ou inferiores a –0,30 MPa foram prejudiciais à germinação não havendo desenvolvimento de plântulas normais a partir de –0,50 Mpa.(AU)