ABSTRACT. In vitro culture systems based on liquid culture media are considered to be more effective than semisolid culture medium systems. Liquid culture media systems provide better nutrient availability for plant tissues, easier culture handling, and the potential for scaling up and automation. However, in vitro liquid culture requires more careful handling due to the potential for contamination and the possibility of negative effects, such as hyperhydricity or vitrification, that hinder the growth and development of the plant material. Temporary immersion bioreactors have emerged as a workable alternative for capturing the benefits of liquid media, though semisolid systems are still traditional. Many studies have shown that silicon (Si) is a beneficial plant nutrient. Silicon might have a positive effect in both semisolid and liquid in vitro systems. The objective of this study was to evaluate the effect of silicon on the micropropagation and acclimatization of banana plants cultivated in vitro by comparing liquid temporary immersion bioreactor technology and semisolid traditional culture systems. Different silicon concentrations (0 and 1 mL L-1) and culture systems (liquid temporary immersion bioreactor and semisolid traditional culture) were evaluated over a 36-day period. The growth characteristics plant size, fresh and dry weight, and number and length of leaves and roots were evaluated. After the 36-day in vitro growth period, plants were transferred to a greenhouse for acclimatization and were evaluated after 30 days for the same growth characteristics used in the in vitro studies. The temporary immersion bioreactor system resulted in greater growth of banana plants compared to the traditional semisolid system. Temporary immersion bioreactors also showed a positive interaction with Si and resulted in higher values for all growth characteristics in the acclimatization phase.

ABSTRACT Banana (Musa spp.) is a crop with outstanding economic and social expression throughout the world. The objective of this study was to investigate the effect of different mulches types in growth production and postharvest of banana ‘BRS Platina’ not irrigated. The experiment was conducted in the farm of the Federal University of Lavras (UFLA). Micropropagated banana plants of the cultivar BRS were planted in the field with a spacing of 2.5 × 3.0 m (1333 plants ·ha-1), without irrigation. About 20 days after planting, different mulches were installed: black polyethylene films, double-sided polyethylene films (white and black), organic mulch (from the own crop) and control (bare soil). The experimental was set up in a randomized block design with four treatments, six blocks and six plants per treatment, totaling 144 plants. Among the six plants used in each treatment, two constituted the border, therefore four plants were evaluated. The analysis performed in the first and second crop were: growth analysis, postharvest quality, production and productivity. Both organic and inorganic (plastic film) mulch provide greater growth and yield of banana ‘BRS Platina’ not irrigated, in two years of production and can be used in the cultivation of this crop.

Resumo: O objetivo deste trabalho foi avaliar o efeito da adubação silicatada nas trocas gasosas, na anatomia foliar e nas características ultraestruturais de maracujazeiro (Passiflora edulis). Os tratamentos consistiram em quatro concentrações (0, 0,28, 0,55, e 0,83 g por vaso) de silício, na forma de solução de ácido silícico (SiO2.XH2O) a 1%. Esta solução foi aplicada ao redor do caule das plantas. A primeira aplicação foi realizada 15 dias após o transplantio das mudas. No total, foram realizadas três aplicações, em intervalos de 15 dias. Os vasos que constituíram o controle (testemunha) receberam água na mesma quantidade. Após a última aplicação, as plantas foram submetidas a análises de trocas gasosas, alterações anatômicas e características ultraestruturais. O uso de silício promove mudanças anatômicas em mudas de maracujazeiro, como o aumento da espessura da epiderme adaxial, a redução do parênquima paliçádico e a maior relação diâmetro polar/diâmetro equatorial, que está relacionada à funcionalidade dos estômatos. As concentrações de 0,55 e 0,83 g de silício por vaso proporcionam maiores taxas fotossintéticas, de transpiração e de condutância estomática das mudas de maracujazeiro. A concentração de 0,83 g de silício por vaso proporciona maior deposição de silício na epiderme abaxial da superfície foliar.

Abstract: The objective of this work was to evaluate the effect of silicon fertilization on gas exchange, leaf anatomy, and ultrastructural characteristics of passion fruit (Passiflora edulis). The treatments comprised four concentrations of silicon (0, 0.28, 0.55, and 0.83 g per pot) at 1% silicic acid solution (SiO2.XH2O). This solution was applied around the stems of the plants. The first application was made 15 days after seedlings were transplanted. In total, three applications were made at 15-day intervals. The pots that constituted the control treatment received water in the same amount. After the final application, the plants were subjected to analyses of gas exchange, anatomical changes, and ultrastructural characteristics. The use of silicon promotes anatomical changes in passion fruit seedlings, such as increased adaxial epidermis thickness, reduced palisade parenchyma, and increased polar diameter/equatorial diameter ratio, which is related to stomata functionality. The concentrations of 0.55 and 0.83 g silicon per pot provide higher rates of photosynthesis, of transpiration, and stomatal conductance. The concentration of 0.83 g silicon per pot results in the greatest deposition of silicon in the abaxial epidermis of leaf surface.

Resumo: O objetivo deste trabalho foi avaliar o efeito de concentrações de silício e ágar no desenvolvimento in vitro de crista-de-galo (Celosia cristata) (Amaranthaceae). Análises fitotécnicas, anatômicas e ultraestruturais foram conduzidas em delineamento inteiramente casualizado, em arranjo fatorial 4x3, com quatro concentrações de ácido silícico (0,0, 0,5, 1,0 e 1,5 g L-1) e três de ágar (5,5, 8,0 e 10,5 g L-1), no total de 12 tratamentos com sete repetições. Explantes de C. cristata foram inoculados in vitro em meio de cultura Murashige & Skoog (MS ), com 30 g L-1 de sacarose. As análises foram realizadas 30 dias após a inoculação. As características fitotécnicas melhoram com a concentração de ágar a 8,0 g L-1, e a associação dessa concentração com 1,0 g L-1 de silício contribui ainda para a melhoria dos atributos anatômicos, principalmente a largura do limbo foliar e a espessura dos parênquimas paliçádico e esponjoso, o que colabora para o desenvolvimento de C. cristata. Nenhuma das combinações avaliadas de silício e ágar contribui para deposição de Si na epiderme foliar dessa espécie ornamental.

Abstract: The objective of this work was to evaluate the effect of silicon and agar concentrations on cockscomb (Celosia cristata) (Amaranthaceae) development in vitro. Phytotechnical, anatomical, and ultrastructural analyses were carried out in a completely randomized design, in a 4x3 factorial arrangment, with four silicic acid concentrations (0.0, 0.5, 1.0, and 1.5 g L-1) and three agar concentrations (5.5, 8.0, and 10.5 g L-1), totaling 12 treatments with seven replicates. Celosia cristata explants were inoculated in vitro in a Murashige & Skoog (MS) culture medium, with 30 g L-1 sucrose. The analyses were conducted 30 days after inoculation. Phytotechnical traits improve with agar concentration of 8.0 g L-1, and the association of this concentration with 1.0 g L-1 silicon also contributes to the improvement of anatomical attributes, especially of leaf blade width and thickness of the palisade and spongy parenchyma, which contributes to the development of C. cristata. None of the evaluated combinations of agar and silicon contributes to Si deposition on the foliar epidermis of this ornamental species.

RESUMO. Butia capitata (Mart.) Becc. é uma palmeira nativa do bioma Cerrado, popularmente denominada coquinho azedo. Espécie considerada em extinção, devido a exploração extrativista intensiva de seus frutos, apresentando como agravante a propagação seminífera lenta e desuniforme. Por isso, existem alguns gargalos relacionados a produção dessa palmeira que precisa ser otimizado. A qualidade e intensidade de luz são muito importantes para a produção de mudas, pois controla o metabolismo das plantas e consequentemente seu crescimento e desenvolvimento. Assim, objetivou-se avaliar o efeito de malhas fotoconversoras no crescimento e aspectos fisiológicos de mudas de coquinho azedo. O delineamento experimental foi inteiramente casualizado, com cinco tratamentos, dez repetições e oito plantas por repetição, totalizando 400 plantas. Os tratamentos consistiram da utilização de malhas fotoconversoras com 50% de sombreamento, sob diferentes radiações proporcionadas: branca (985 µmol m-2 s-1), vermelha (327 µmol m-2 s-1), preta (433 µmol m-2 s-1), e prata (405 µmol m-2 s-1). As plantas mantidas a pleno sol (1000 µmol m-2 s-1) foram consideradas como o tratamento controle. Após seis meses foram realizadas análises de crescimento e fisiológicas. Conclui-se que a malha vermelha proporciona maior crescimento e aumento de biomassa das plantas de Butia capitata. No entanto, o uso de malhas fotoconversoras não influenciam nas características fisiológicas dessa espécie. A malha vermelha é a mais adequada para a produção de mudas de Butia capitata nas condições do Sul de Minas Gerais.

ABSTRACT. Butia capitata (Mart.) Becc., commonly known as jelly palm, is a palm tree native to the Cerrado biome. It is considered an endangered species owing to intensive extractive exploitation of its fruits, with slow and uneven seminiferous propagation as an aggravating factor. Thereby, there are some bottlenecks related to jelly palm seedling production that needs to be optimized. Light quality and intensity is very important to seedling production, as it controls the metabolism of plants and consequently their growth and development. Thus, the aim of this work is to evaluate the effect of shade nets on the growth and physiological aspects of jelly palm seedlings. The experimental design was completely randomized, with five treatments, ten replicates and eight plants per replicate, totaling 400 plants. Experimental treatments consisted of the use of shade nets with 50% shading and different radiation intensity: white (985 µmol m-2 s-1), red (327 µmol m-2 s-1), black (433 µmol m-2 s-1), and silver (405 µmol m-2 s-1). Full sun (1000 µmol m-2 s-1) was used as the control treatment. Growth and physiological analyses of the plants were performed after six months of treatment. We concluded that the red shade net increases growth and biomass of Butia capitata plants. However, the use of shade nets had no effect on the tested physiological characteristics of this species. The red shade net is the most suitable for the production of Butia capitata seedlings in the southern region conditions of Minas Gerais State.

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.