Abstract This study aimed to evaluate the effect of fruit maturation stages and pre-germination treatments with plant regulators on the physiological quality of seeds of cv. BRS Mel do Cerrado. Two experiments were carried out, germination and emergence, installed in a completely randomized design in a 3 x 2 factorial arrangement, with three stages maturation (1-partially ripe fruits; 2-fully ripe fruits and 3-senescent fruits) and two pre-germination treatments (1. [GA4+7 +N-(phenylmethyl)-aminopurine (300 ppm)] and 2. distilled water), forming six treatments with four replications of 50 seeds. The evaluated characteristics were germination percentage at 14 and 35 days, germination speed index (GSI), emergence percentage and emergence speed index (ESI). Germination at 14 days, GSI and seedling emergence were not affected by the maturation stage, however germination and GSI were higher when the plant regulator was used. The final percentage of germination was higher in seeds taken from partially ripe fruits and treated with regulators and a higher ESI was observed for seeds from senescent fruits and treated with regulator. Seeds treated with plant regulators are more vigorous and have a higher rate of seedling emergence.

Resumo Este trabalho teve como objetivo avaliar o efeito de estádios de maturação de frutos e de tratamentos pré-germinativos com reguladores vegetais na qualidade fisiológica das sementes de maracujá doce cv. BRS Mel do Cerrado. Foram realizados dois experimentos, de germinação e de emergência, instalados em delievalneamento inteiramente casualizado, em arranjo fatorial 3 x 2, sendo três estádios dematuração (1-frutos parcialmente maduros; 2-frutos totalmente maduros, e 3-frutossenescentes) e dois tratamentos pré-germinativos (1. [GA4+7 +N-(fenilmetil)-aminopurina(300 ppm)]e 2. água destilada), formando seis tratamentos com quatro repetições de 50sementes. As características avaliadas foram percentagem de germinação, aos 14 e 35 dias, índice de velocidade de germinação (IVG), percentagem de emergência e índice de velocidade deemergência(IVE). A germinação, aos 14 dias, o IVG e a emergência de plântulas não foramafetados pelos estádios de maturação; entretanto, a germinação e o IVG foram maioresquando se utilizaram os reguladores vegetais. A porcentagem final de germinação foi maior para sementes retiradas de frutos parcialmente maduros e tratadas com reguladoresvegetais e observou-se maior IVE para sementes de frutos senescentes e tratadas comreguladores. Sementes tratadas com reguladores vegetais são mais vigorosas e apresentam maior velocidade de emergência de plântulas.

Resumo O objetivo deste trabalho foi avaliar a indução de organogênese indireta por concentrações de ácido diclorofenoxiacético (2,4-D) e tidiazurom (TDZ) em explantes de pitaia (Hylocereus undatus), por meio de microscopia eletrônica de varredura e da técnica de citometria de fluxo. Os tratamentos consistiram das concentrações de 0, 2,0 e 4,0 mg L-1 de 2,4-D e TDZ e das combinações desses reguladores. Avaliaram-se as percentagens de cobertura de calos aos 45 e 60 dias. Os explantes submetidos aos tratamentos foram analizados por citometria de fluxo e microscopia eletrônica de varredura. Todos os tratamentos induziram endorreduplicação, e não houve variação somaclonal. Na combinação de 2,0 mg L-1 TDZ e 4,0 mg L-1 2,4-D, calos foram formados em 95% dos explantes, mas foram menores do que os produzidos com 2,4-D separadamente. A concentração de 2,0 mg L-1 de TDZ induz organogênese indireta em explantes de pitaia, comprovada pela presença de vasos condutores por meio da microscopia eletrônica de varredura.

Abstract The objective of this work was to evaluate the induction of indirect organogenesis by concentrations of dichlorophenoxyacetic acid (2,4-D) and thidiazuron (TDZ) in pitaya (Hylocereus undatus) explants, using scanning electron microscopy and the flow cytometry technique. The treatments consisted of the concentrations of 0, 2.0, and 4.0 mg L-1 2,4-D and TDZ and of the combinations of these regulators. Percentages of callus coverage at 45 and 60 days were evaluated. The explants subjected to the treatments were analized by flow cytometry and scanning electron microscopy. All treatments induced endoreduplication, and there was no somaclonal variation. Under the combination of 2.0 mg L-1 TDZ and 4.0 mg L-1 2,4-D, calluses were formed in 95% of the explants, but were smaller than those produced with 2,4-D separately. The concentration of 2.0 mg L-1 TDZ induces the indirect organogenesis in pitaya explants, confirmed by the presence of conducting vessels through scanning electron microscopy.

ABSTRACT. Given the high demand for food worldwide, options for maximizing food production with minimum environmental impact are needed. Therefore, the objective of the present study was to evaluate the effect of silicon (Si) and methyl jasmonate (MeJA) in the vegetative development and genetic stability of rice plants, BRSMG Caravera cultivar. The treatments used were T1 - Control group (without Si and MeJA); T2 - Tween foliar; and T3 - Si drench, T4 - MeJA foliar, and T5 - Si drench + MeJA foliar. The use of Si or Si + MeJA promoted an increase in the height, relative chlorophyll index (RCI), and fresh and dry masses, in addition to a greater Si accumulation in the plants. However, there was no difference in the quantity of DNA or in the coefficient of variation (CV) among the treatments, proving the use of silicon separately or in combination with methyl jasmonate contributed to the vegetative development and did not affect the genetic stability of the plants.

RESUMO. O objetivo foi determinar uma concentração de silício que proporcionasse um bom crescimento de plantas de maracujá. Sementes de maracujazeiro foram semeadas em bandejas de poliestireno, após 60 dias, as plantas com aproximadamente 15 cm de altura, foram transplantadas para vasos de polietileno contendo 1,1 kg de substrato Tropstrato(r). Os tratamentos consistiram de quatro concentrações (0; 0,28; 0,55 e 0,83 g vaso-1) de silício, na forma de solução de ácido silícico a 1%. Esta solução foi aplicada ao redor do caule das plantas (drench), sendo a primeira aplicação realizada 15 dias após o transplantio das plantas. No total, foram realizadas três aplicações, em intervalos de 15 dias. Após a última aplicação, as plantas foram submetidas à análise química de concentração de silício, microanálise de raios-X e citometria de fluxo. As análises fitotécnicas foram realizadas no decorrer das aplicações. O uso do silício nas concentrações 0,28 e 0,55 g vaso-1, proporciona melhor crescimento das plantas de maracujazeiro, a absorção de silício e sua deposição nas folhas de maracujazeiro são proporcionais à disponibilidade desse elemento para a planta, o maracujazeiro é uma planta acumuladora de silício nas raízes e a estabilidade da quantidade de DNA é preservada nas plantas de maracujazeiro tratadas com silício.

ABSTRACT. The objective of this study was to determine the silicon concentration that would provide good growth in passion fruit plants. Passion fruit seeds were sown in polystyrene. After 60 days, when they were approximately 15 cm tall, the plants were transplanted into polyethylene pots containing 1.1 kg Tropstrato(r) substrate. Treatments consisted of four concentrations (0, 0.28, 0.55, and 0.83 g pot-1) of silicon applied as a silicic acid solution 1%. This solution was applied around the stem of the plants (drenched), with the first application being administered 15 days after transplanting. In total, three applications were made at intervals of 15 days. After the last application, the plants were subjected to chemical analysis to determine the silicon concentration and to X-ray microanalysis and flow cytometry. Phytotechnical analyses were performed during the applications. The use of silicon in concentrations of 0.28 and 0.55 g pot-1 provides better growth of the passion fruit, and the absorption and deposition of the silicon in the passion fruit leaves are proportional to the availability of this element in the plant. The roots of the passion fruit plant are silicon accumulators, and the DNA stability and amount are preserved in the silicon-treated passion fruit plants.