Effect of two sources of zinc on the physiological quality of seed and nutrition of rice (Oriza sativa) seedlings

Rice seeds coating with microparticulate zinc oxide can maximize the absorption of this micronutrient by the seedling and favor seeds vigor when compared with zinc sulfate. This work aimed to evaluate the sources and doses of zinc in seed quality and in the nutrition of rice seedlings. The experiment consisted of a completely randomized design with four replications, five doses of zinc in the form of oxide (0; 20; 40, 80 and 160 g kg-1), and a control treatment of zinc in the form of sulfate (40 g kg-1). The following parameters were evaluated: germination, accelerated aging, seedlings emergence, emergence speed index, cold test, dry matter, and zinc concentration in the root and shoot of the seedlings. Seed coating with zinc, regardless of the source, improved seed physiological quality and seedling nutrition of the rice cultivar. Zinc sources did not change the germination; however, the oxide form provided better seed vigor, except for the highest dose (160 g kg-1). The increase in the dose of zinc oxide increased the concentration of this nutrient in rice seedlings dry matter. Zinc coating of rice seeds in the form of microparticulate, depending on the dose, can maximize the seeds vigor and increase the concentration of this micronutrient in the seedlings when compared with zinc sulfate, which is the traditional source used by producers. Highlights Zinc (Zn) coating does not affect germination, but influences the vigor of rice seeds. The Zn sources affect the Zn concentration in the shoot dry matter. Both ZnO and ZnSO 4 showed higher shoot dry matter, when compared with the absence of Zn in rice seeds. Oxide zinc (ZnO) promotes greater root dry matter of rice when compared with zinc sulfate (ZnSO 4 ).Rice seeds coating with microparticulate zinc oxide can maximize the absorption of this micronutrient by the seedling and favor seeds vigor when compared with zinc sulfate. This work aimed to evaluate the sources and doses of zinc in seed quality and in the nutrition of rice seedlings. The experiment consisted of a completely randomized design with four replications, five doses of zinc in the form of oxide (0; 20; 40, 80 and 160 g kg-1), and a control treatment of zinc in the form of sulfate (40 g kg-1). The following parameters were evaluated: germination, accelerated aging, seedlings emergence, emergence speed index, cold test, dry matter, and zinc concentration in the root and shoot of the seedlings. Seed coating with zinc, regardless of the source, improved seed physiological quality and seedling nutrition of the rice cultivar. Zinc sources did not change the germination; however, the oxide form provided better seed vigor, except for the highest dose (160 g kg-1). The increase in the dose of zinc oxide increased the concentration of this nutrient in rice seedlings dry matter. Zinc coating of rice seeds in the form of microparticulate, depending on the dose, can maximize the seeds vigor and increase the concentration of this micronutrient in the seedlings when compared with zinc sulfate, which is the traditional source used by producers. Highlights Zinc (Zn) coating does not affect germination, but influences the vigor of rice seeds. The Zn sources affect the Zn concentration in the shoot dry matter. Both ZnO and ZnSO 4 showed higher shoot dry matter, when compared with the absence of Zn in rice seeds. Oxide zinc (ZnO) promotes greater root dry matter of rice when compared with zinc sulfate (ZnSO 4 )

ÁCIDO GIBERÉLICO AUXILIA NA SUPERAÇÃO DA DORMÊNCIA FISIOLÓGICA E EXPRESSÃO DE VIGOR DAS SEMENTES DE GRAVIOLA

As sementes de graviola (Annona muricata) apresentam tegumento resistente e impermeável, além de substâncias inibidoras que dificultam a germinação das sementes. Assim, objetivou-se avaliar a contribuição da embebição em ácido giberélico para a superação da dormência e aumento da germinação das sementes de graviola. O delineamento experimental foi inteiramente casualizado, com cinco tratamentos e quatro repetições. As sementes foram escarificadas e em seguida embebidas por 24 horas a 25 ºC em soluções contendo 0; 50; 100; 150 e 200 mg L-1 (ppm) de ácido giberélico. Após este período de embebição as sementes foram submetidas ao teste de germinação, sendo avaliados a porcentagem de germinação, o índice de velocidade e o tempo médio de germinação. As concentrações de ácido giberélico apresentaram efeito sobre a germinação e índice de velocidade de germinação. Conclui-se que a embebição das sementes de graviola na concentração aproximada de 140 ppm de ácido giberélico auxilia na superação da dormência, aumentando a germinação e o índice de velocidade de germinação

Metodologia para a condução do teste de germinação em sementes de goiaba

RESUMOMesmo sabendo-se que comercialmente a propagação da goiabeira deve ser via assexual, o emprego de sementes torna-se obrigatório nos programas de melhoramento e na produção de porta-enxertos, porém poucos trabalhos são encontrados sobre metodologias para análise de sementes dessa espécie, fato que pode ser comprovado através das Regras para Análise de Sementes, onde não há recomendação para o teste de germinação. Dessa forma, objetivouse com este trabalho determinar a metodologia quanto à temperatura, substrato e tempo de contagem para o teste de germinação em sementes de goiaba. As temperaturas avaliadas foram: 20; 25 e 30 oC constantes e 20-30 oC alternada e os seguintes substratos: rolo de papel, sobre papel, entre areia e sobre areia. O efeito das temperaturas e substratos sobre o desempenho das sementes foi avaliado pelo teste de germinação, índice de velocidade e tempo médio de germinação. O experimento foi instalado em delineamento inteiramente casualizado, com os tratamentos distribuídos em esquema fatorial 4 x 4 (temperaturas x substratos), com quatro repetições. Nas condições testadas, concluiu-se que o teste de germinação em sementes de goiaba pode ser realizado à temperatura alternada de 20-30 ºC, no substrato rolo de papel, sobre papel ou sobre areia e com contagem final aos 23 dias da semeadura

GERMINATION TEST IN SEEDS OF MELOTHRIA CAMPESTRIS (NAUDIN) H. SCHAEF. & S.S. RENNER

The Cerrado occupies 25% of the Brazilian territory and is the second largest biome in South America, second only to the Amazon Rainforest. Hence, studies on the native species of the Cerrado are important for implementing conservation strategies. In this context, knowledge of the requirements and conditions for germination of seeds of these native species is essential. The Cerrado watermelon ( Melothria campestris (Naudin) H. Schaef. & S.S. Renner) is a plant that is not cultivated, but has been used in revegetation projects in the countryside of the Cerrado because its fruits are fed upon by fauna in times of food shortage. The purpose of this study was to determine the most appropriate methodology for the germination of the Cerrado watermelon, by identifying the best - suited substrate, the optimal temperature, and the corresponding time taken for germination . The treatments consisted of four substrates: in a paper roll, on paper, in sand, and on sand; and four temperatures: 20, 25, and 30 °C (maintained constant), and a fourth temperature treatment that alternated 20 - 30 °C. The effect of the substrates and temperatures on seed performance was evaluated using the germination test, speed index, and average time for germination. The experimental design was fully randomized, with treatments distributed in a 4 × 4 (substrates × temperatures) factorial scheme, with four replications. Our results show that the temperature of 20 °C had a negative influence on germination in all substrates. Further, we found that the germination of the Cerrado watermelon seeds was best in a paper roll or on sand substrate, maintained at a constant temperature of 30 °C, or when temperature was alternated 20 - 30 °C, and the time required for germination stabilization was 30 days

Atividade fitotóxica de Croton doctoris S. Moore Phytotoxic activity of Croton doctoris S. Moore

O objetivo deste trabalho foi caracterizar o efeito fitotóxico do extrato etanólico bruto e frações semipurificadas do caule e folhas de C. doctoris na germinação, crescimento inicial e divisão celular das células radiculares de alface (Lactuca sativa) e cebola (Allium cepa), em laboratório. O experimento foi realizado em delineamento inteiramente casualizado, sendo utilizadas quatro concentrações dos tratamentos (0, 250, 500, 1.000mg L-1), com quatro repetições. O extrato bruto e as frações do caule e folhas inibiram a germinação e crescimento de alface e cebola, sendo o maior efeito fitotóxico promovido pela fração acetato de etila (FAE) do caule e folhas que afetou significativamente o crescimento e índice mitótico das células radiculares de alface e cebola. Com os resultados obtidos, verifica-se que a espécie C. doctoris apresenta substâncias capazes de influenciar no crescimento e divisão celular das espécies avaliadas.The aim of this study was to verify the phytotoxic effect of the crude ethanol extract and semipurified fractions from the stem and leaves of Croton doctoris on the germination, growth and cell division of roots cells of lettuce (Lactuca sativa) and onion (Allium cepa), in the laboratory. The bioassays was conducted in using completely randomized design, with four concentrations (0, 250, 500, 1.000mg L-1) and four replications. The crude extract and the fractions from the stem and leaves inhibited germination and seedling growth of lettuce and onion, with greater phytotoxic effect observed in the ethyl acetate fraction (EAF) from the stems and leaves that significantly affected the growth and mitotic index of root cells of lettuce and onions. With these results it appears that C. doctoris contains substances capable of influencing the germination, growth and cell division of the species studied

Phytotoxic potential of Senna occidentalis and Senna obtusifolia - doi: 10.4025/actascibiolsci.v32i3.5833

This work aimed to investigate the phytotoxic potential of the aerial and underground parts of Senna occidentalis and S. obtusifolia on the germination and initial growth of lettuce and onion. Four concentrations were used of each ethanol extract (0, 250, 500 and 1000 mg L-1), with four replications of 50 seeds. From the investigated species, the aerial part of S. occidentalis interfered in onion germination and the aerial part of S. obtusifolia interfered in the germinations of lettuce and onion. The ethanol extract from the aerial and underground parts of the studied species inhibited the root growth of lettuce and onion. The hypocotyl/coleoptile growth in lettuce and onion was inhibited by the extract of S. obtusifolia aerial part and the underground part of S. occidentalis and S. obtusifolia. The results obtained make it possible to infer that the studied species contain substances that influence the germination and growth of the target seedlings.This work aimed to investigate the phytotoxic potential of the aerial and underground parts of Senna occidentalis and S. obtusifolia on the germination and initial growth of lettuce and onion. Four concentrations were used of each ethanol extract (0, 250, 500 and 1000 mg L-1), with four replications of 50 seeds. From the investigated species, the aerial part of S. occidentalis interfered in onion germination and the aerial part of S. obtusifolia interfered in the germinations of lettuce and onion. The ethanol extract from the aerial and underground parts of the studied species inhibited the root growth of lettuce and onion. The hypocotyl/coleoptile growth in lettuce and onion was inhibited by the extract of S. obtusifolia aerial part and the underground part of S. occidentalisand S. obtusifolia. The results obtained make it possible to infer that the studied species contain substances that influence the germination and growth of the target seedlings

ÁCIDO GIBERÉLICO AUXILIA NA SUPERAÇÃO DA DORMÊNCIA FISIOLÓGICA E EXPRESSÃO DE VIGOR DAS SEMENTES DE GRAVIOLA

As sementes de graviola (Annona muricata) apresentam tegumento resistente e impermeável, além de substâncias inibidoras que dificultam a germinação das sementes. Assim, objetivou-se avaliar a contribuição da embebição em ácido giberélico para a superação da dormência e aumento da germinação das sementes de graviola. O delineamento experimental foi inteiramente casualizado, com cinco tratamentos e quatro repetições. As sementes foram escarificadas e em seguida embebidas por 24 horas a 25 ºC em soluções contendo 0; 50; 100; 150 e 200 mg L-1 (ppm) de ácido giberélico. Após este período de embebição as sementes foram submetidas ao teste de germinação, sendo avaliados a porcentagem de germinação, o índice de velocidade e o tempo médio de germinação. As concentrações de ácido giberélico apresentaram efeito sobre a germinação e índice de velocidade de germinação. Conclui-se que a embebição das sementes de graviola na concentração aproximada de 140 ppm de ácido giberélico auxilia na superação da dormência, aumentando a germinação e o índice de velocidade de germinação