Abstract In vitro flowering is a technique used in genetic improvement that accelerates generations and favors the faster fixation of new traits of agronomic and market interest. The study aimed to establish a protocol for the in vitro flowering of Dendrobium nobile, through the combined temperature and of the growth regulator thidiazuron (TDZ) effects. Experiments was performed in a flask that was kept in a BOD incubator at 18, 21, or 24 °C or in a growth room at 26 °C. The TDZ concentrations were 0.0, 0.5, 1.0, and 2.0 mg L-1. The highest percentage of flowering shoots of 13.7% occurred at a concentration of 2 mg L-1 of TDZ grown at a temperature of 18 °C. Dendrobium nobile in vitro flowering was promoted in plants cultivated in ½ MS supplemented with 30 g L-1 sucrose, 5.5 g L-1 agar, 100 mL L-1 coconut water, pH 6.0, and 2.0 mg L-1 TDZ at a controlled temperature of 18 °C and a photoperiod of 16 h. The in vitro flowering induction protocol of the D. nobile species could be used or improved for future studies.

Resumo A floração in vitro é uma técnica utilizada no melhoramento genético que acelerar gerações e favorecer a fixação mais rápida de novos caracteres de interesse agronômico e do mercado. O estudo visou estabelecer um protocolo para a floração in vitro de Dendrobium nobile, através dos efeitos combinados de temperatura e do regulador de crescimento thidiazuron (TDZ). Os experimentos foram realizados em incubadora tipo BOD a 18, 21, 24 °C e, em sala de crescimento a 26 °C. As concentrações de TDZ testadas foram de 0,0, 0,5, 1,0 e 2,0 mg L-1. A maior porcentagem de brotos floridos de 13,70% ocorreu na concentração de 2 mg L-1 de TDZ cultivados em temperatura de 18 °C. O florescimento in vitro de D. nobile foi promovido em plantas cultivadas em ½ MS suplementadas com 30 g L-1 de sacarose, 5,5 g L-1 de ágar, 100 mL L-1 de água de coco, pH 6,0 e 2,0 mg L-1 de TDZ em temperatura controlada de 18 °C e fotoperíodo de 16 h. O protocolo de indução de florescimento in vitro da espécie D. nobile poderá ser utilizado ou aprimorado para estudos futuros.

Abstract Light quality is an important factor for the adequacy of plant production through plant tissue culture, as it directly interferes with morphogenesis and photosynthetic capacity of explants. The objective of this study was to analyze the impact of monochromatic lights such as light emitting diode (LED) on the in vitro development of Cattleya walkeriana G. and their effects on acclimatization. The plants were developed in vitro under the colors of green, blue, yellow, red, 2 red:1 blue, and white LED lights. For in vitro cultivation, Knudson medium was used, supplemented with 20 mg L-1 sucrose, 5.5 mg L-1 agar, 2% activated charcoal, 100 mL coconut water, and pH 6.0. For ex vitro cultivation, the plants were acclimatized in styrofoam trays containing sphagnum as a substrate. In general, the supplied light lengths impactedin vitro growth and acclimatization analyses. There was influence on the cuticle thickness of plants in vitro. Chlorophyll and carotenoid contents were not significant. We can conclude that light lengths formed by 2 red:1 blue, red and yellow LEDs can be indicated for better performance in the production of C. walkeriana. The 2 red:1 blue and red LEDs provide superior in vitro development than the others, with gains for the species in acclimatization. The yellow LED provided a possible in vitro hardening, which ensured the greatest success of the seedlings during acclimatization.

Resumo A qualidade luminosa é um fator importante para a adequação da produção de plantas através da cultura de tecidos vegetais, pois interfere diretamente nos processos de morfogênese e na capacidade fotossintéticas dos explantes. O objetivo deste estudo foi analisar o impacto de luzes monocromática do tipo diodo emissor de luz (light-emittingdiode - LED) no desenvolvimento in vitro de Cattleya walkeriana G. e os efeitos na fase aclimatização. As plantas foram desenvolvidas in vitro sob as cores de luzes do tipo LED verde, azul, amarelo, vermelho, 2 vermelhos: 1 azul, e branco. Para cultivo in vitro foi utilizado o meio Knudson acrescido de 20 mg L-1 de sacarose, 5,5 mg L-1 de ágar, 2% de carvão ativado, 100 mL de água de coco, e pH 6,0. Para o cultivo ex vitro as plantas foram aclimatizadas em bandejas de isopor contendo esfagno como substrato. De maneira geral, os comprimentos luminosos fornecidos apresentaram impactos nas análises de crescimento in vitro e na de aclimatização. Houve influência na espessura da cutícula das plantas in vitro. Os teores de clorofilas e carotenoides não foram significativos. Podemos concluir, que comprimentos luminosos formados pelos LEDs 2 vermelhos: 1 azul, vermelho e amarelo podem ser indicados para melhor desempenho na produção de C. walkeriana. Os LEDs 2 vermelhos: 1 azul, e o LED vermelho propiciam desenvolvimento in vitro superior ao demais com ganhos na fase de aclimatização para espécie. O LED amarelo propiciou um possível processo de rustificação in vitro o que garantiu o maior sucesso das mudas no período de aclimatização.

Abstract Diatomaceous earth is an organic naturally occurring material rich in silicon. This silicon source can be used in organic agriculture, it also has a great potential of use in the acclimatization of crops. However, there are no reports of the effects of diatomaceous earth supplementation on the micropropagation of sweet potato. Thus, the objective of this study was to evaluate the effects of different concentrations of diatomaceous earth applied in vitro on the growth, physiology and anatomy of sweet potato cv. ‘Brazlândia Branca’ after acclimatization. Four concentrations of diatomaceous earth. After 30 days of in vitro growth, the plants were transferred to a greenhouse for acclimatization. After 45 days, leaf number, shoot and root length, fresh and dry shoot and root mass, gas exchange, chlorophyll content, root and leaf anatomy. The experimental design was completely randomized. The supplementation of diatomaceous earth in the in vitro cultivation had beneficial effects, increasing the accumulation of mass, improving the photosynthetic apparatus and promoting favorable anatomical characteristics during the acclimatization of the sweet potato plants. In addition, the use of diatomaceous earth achieved adequate seedling development, with higher seedling quality and resistance to biotic and abiotic effects than attained with control treatment.

ABSTRACT: Effective protocols for in vitro rooting for woody fruit trees are still a challenge for in vitro seedling production, especially when there is a need to insert new cultivars or rootstocks. These protocols are essential to accelerate studies in plant breeding programs and for seedling distribution. This study evaluated the use of 6-Benzylaminopurine (IBA) in in vitro rooting of Pyruscomunnis rootstocks, clones ‘OHxF87’ and Pyrodwarf. Explant exposure times (0, 24, 48, 72, and 96 hours) to 20 mg L-1 IBA were tested for in vitro rooting. The exposure to IBA resulted in rooting rates above 80%, surpassing some results reported in the literature. The 24-hour treatment provided 81,81% survival, leading to an average growth of five roots with 19 mm length, for ‘OHxF87’ rootstock. The same exposure time resulted in the highest survival rate (75%) and the highest mean root number, seven roots per plant with 10 mm length, for ‘PDW’ rootstock. Root formation did not occur in the absence of synthetic auxin. Therefore, it can be concluded that a 24-hour exposure at 20 mg L-1 IBA was sufficient to promote in vitro rooting in ‘OHxF87’ and Pyrodwarf rootstocks’.

RESUMO: Protocolos eficazes de enraizamento in vitro de frutíferas lenhosas ainda são um desafio para produção de mudas in vitro, especialmente quando há necessidade de inserção de novas cultivares ou porta-enxerto. Esses protocolos são essenciais para acelerar estudos nos programas de melhoramento genético e também para distribuição posterior das mudas. Nesse sentido, o objetivo deste estudo foi avaliar a utilização da 6-Benzilaminopurina no enraizamento in vitro de porta-enxerto Pirus comunnis, clones ‘OHxF87’ e Pyrodwarf. Para o enraizamento, foi testado o tempo de exposição dos explantes ao AIB. Para tanto, foram utilizados 20 mg L-1 do fitohormônio nas horas 0, 24, 48, 72 e 96 horas. A exposição ao AIB resultou em taxas de enraizamento acima de 80%, superando alguns resultados encontrados na literatura. Para o porta-enxerto ‘OHxF87’, o tratamento de 24 horas proporcionou 81,81% de sobrevivência, promovendo em média cinco raízes com comprimento de 19 mm. O mesmo tratamento para o porta-enxerto ‘PDW’ resultou na maior taxa de sobrevivência (75%), bem como no maior número médio de raízes, sete raízes por planta, com comprimento de 10 mm. Na ausência de auxina sintética, a formação de raízes não ocorreu. Assim sendo, podemos concluir que o tempo de exposição de 24 horas a 20 mg L-1 de IBA foi suficiente para promover o enraizamento de porta-enxertos Pyrus communis de ‘OHxF87’ e ‘PDW’.

Abstract The generation of agroindustrial waste has become a serious environmental problem, which conflicts with the need for sustainability sought by modern agriculture. An alternative that helps minimizing these effects is the use of residues, such as fruit peel, in food production. The objective of this study was to evaluate the viability of the mesocarp of the white-fleshed red pitaya (Hylocereus undatus) in the preparation of jellies, verifying the influence of different percentages of pulp replacement per mesocarp (0, 20, 40 and 60%) on the physicochemical, microbiological, and sensorial characteristics of the final products. The jellies presented good acceptability among consumers, with the 60% substitution level being the most accepted. Besides the mesocarp not altering the flavor of the jellies, its use increases the attractiveness to the consumer in addition to contributing to cost reduction and environment preservation.

Resumo O objetivo deste trabalho foi investigar o efeito de reguladores de crescimento de plantas (RCP) na indução de calos a partir de cotilédones de Enterolobium contortisiliquum cultivados in vitro, bem como avaliar a atividade inibitória de tripsina nestes calos. Cotilédones de E. contortisiliquum foram cultivados em meio de cultura suplementado com ácido diclorofenoxiacético (2,4-D), picloram (PIC), cinetina (KIN) e 6-benzilaminopurina (BAP). Foram mensuradas, após 60 dias, massa de calo, atividade inibitória de tripsina, observações morfogenéticas e citoquímicas, e atividade biológica. O diagrama de Pareto mostrou que apenas 0,5 mg L-1 de PIC influenciou o aumento da massa fresca, enquanto 0,5 mg L-1 de BAP influenciou a massa seca. O gráfico de análise de componentes principais mostrou a formação de dois clusters claros. A atividade inibitória de tripsina é alcançada em maior intensidade no tratamento com 0,5 mg L-1 de 2,4-D + 2,0 mg L-1 de PIC + 0,5 mg L-1 de KIN + 2,0 mg L-1 de BAP. A combinação de RCP em diferentes doses causa intensa formação de calo. Baixas concentrações de RCP resultam em maior massa fresca, massa seca e atividade biológica. A utilização de RCP é eficiente na obtenção de calos de E. contortisiliquum com satisfatória atividade inibitória de tripsina.

Abstract The objective of this work was to investigate the effect of plant growth regulators (PGR) on the induction of calli from cotyledons of Enterolobium contortisiliquum grown in vitro, as well as to evaluate the inhibitory activity of trypsin in these calli. Cotyledons of E. contortisiliquum were cultivated in culture medium supplemented with dichlorophenoxyacetic acid (2,4-D), picloram (PIC), kinetin (KIN), and 6-benzylaminopurine (BAP). Callus mass, inhibitory activity of trypsin, morphogenetic and cytochemical observations, and biological activity were measured after 60 days. The Pareto diagram showed that only 0.5 mg L-1 PIC influenced the increase of fresh mass, whereas 0.5 mg L-1 BAP influenced dry mass. The principal component analysis plot showed the formation of two clear clusters. The inhibitory activity of trypsin is achieved at a higher intensity in the treatment with 0.5 mg L-1 2,4-D + 2.0 mg L-1 PIC + 0.5 mg L-1 KIN + 2.0 mg L-1 BAP. The combination of PGR at different rates causes an intense callus formation. Low concentrations of PGR result in a higher fresh mass, dry mass, and biological activity. The use of PGR is efficient in obtaining E. contortisiliquum calli with a satisfactory inhibitory activity of trypsin.

Abstract To produce pitaya (Hylocereus spp.), it is essential that pollination occur, either artificially or by pollinating agents. This study evaluated the viability of self-pollination, cross-pollination, and natural pollination, as well as pollen viability, stigma receptivity and ideal pollination window in pitaya flowers (Hylocereus spp.). An experiment was conducted with a randomized block design consisting of four treatments: T1: manual self-pollination; T2: nocturnal open pollination; T3: diurnal open pollination; and T4: manual cross-pollination - red-fleshed pitaya [ Hylocereus polyrhizus] pollen placed on white-fleshed pitaya [ Hylocereus undatus] stigma. The experiment had four replicates, with two plants per replicate (two flowers per plant), totaling 16 flowers per treatment. The analyzed variables were fruit weight, length, diameter, titratable acidity, pH, soluble solids, and SS/TA ratio; the germination percentage of pollen grains; and the receptivity of stigmas. Artificial pollination (self- and cross-pollination) of white-fleshed pitaya (Hylocereus undatus) is viable, resulting in larger fruits than natural pollination, with cross-pollination being the most recommended. Throughout the floral opening period, the pitaya flower (Hylocereus spp.) has receptive stigma capable of receiving pollen. The flowers exhibit the highest pollen germination rate at 7 p.m, which is the ideal pollination window for pitaya.

ABSTRACT. Many important crops have cultivars with different ploidy and provide a diverse choice of materials for breeding programs. Therefore, it is essential to accurately assess the ploidy of all breeding materials. Increased DNA content is known to have various effects on external and internal morphology, an effect known as the “nucleotypic effect”. Thus, anatomical assessment can be used as a tool for determining ploidy in plants, making the chromosome counting technique or flow cytometry unnecessary. This study aimed to evaluate the leaf anatomical characteristics of banana cultivars and understand the relationship between these features and ploidy levels. Thirteen accessions were evaluated, including diploid, triploid, and tetraploid genotypes, and cultivars, resulting from in vitro propagation after 90 days of acclimatization. Five fully expanded young leaves were collected from each cultivar, fixed in FAA70 (formaldehyde-acetic acid-ethanol) and preserved in 70% alcohol. Transverse and paradermal sections of the abaxial and adaxial regions were taken, and variables such as size and stomatal density, leaf thickness in the midrib and fourth vascular bundle region, and thickness of the epidermis, hypodermis, and parenchyma were measured. Results for leaf thickness, stomatal size, and density proved to be appropriate parameters for characterizing banana ploidy levels.

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 a viabilidade da microenxertia de pitaia amarela (Selenicereus megalanthus) sobre diferentes microporta-enxertos, com base em análises de conteúdo de DNA e anatômicas. Os porta-enxertos utilizados foram: pitaia amarela, pitaia branca (Hylocereus undatus), pitaia Saborosa (Selenicereus setaceus), e as variedades Cebra e Orejona de pitaia vermelha (Hylocereus polyrhizus). O delineamento experimental foi inteiramente casualizado, com cinco tratamentos e quatro repetições de cinco plantas. Após 30 dias de cultivo, avaliaram-se as seguintes características: comprimento e diâmetro dos microenxertos e dos microporta-enxertos; e comprimento de raízes, percentagem de pegamento e massa fresca dos microenxertos. Realizaram-se análises de citometria de fluxo antes e depois da microenxertia, para verificação da estabilidade genética e da ocorrência de endoreduplicação. Além disso, foram feitos cortes histológicos na região da microenxertia, para verificação das conexões dos vasos e dos tecidos entre o enxerto e o porta-enxerto. Observou-se endoreduplicação em todos os tratamentos. A quantidade de DNA do microenxerto de pitaia amarela aumentou sobre a variedade vermelha Orejona. Verificou-se a presença de conexões de vasos entre os microenxertos e os microporta-enxertos. A pitaia amarela também foi mais vigorosa quando enxertada sobre Orejona. Com base nas análises de conteúdo de DNA e anatômicas, a microenxertia de pitaia amarela in vitro é viável em todos os porta-enxertos utilizados.

Abstract The objective of this work was to evaluate the viability of the micrografting of yellow dragon fruit (Selenicereus megalanthus) on different rootstocks, based on DNA content and anatomical analyses. The used rootstocks were: yellow dragon fruit, white dragon fruit (Hylocereus undatus), Saborosa (Selenicereus setaceus) dragon fruit, and the Cebra and Orejona red dragon fruit (Hylocereus polyrhizus) varieties. The experimental design was completely randomized with five treatments and four replicates of five plants. After 30 days of cultivation, the following traits were evaluated: length and diameter of the micrografts and microrootstocks; and root length, percentage of setting, and fresh mass of the micrografts. Flow cytometry analyzes were performed before and after micrografting to verify genetic stability and the occurrence of endoreduplication. In addition, histological sections were made in the micrografting region to verify the connections of vessels and tissues between the graft and the rootstock. Endoreduplication was observed in all treatments. The amount of DNA in the yellow dragon fruit micrograft increased on the red Orejona variety. The presence of vessel connections was verified between the micrografts and microrootstocks. The yellow dragon fruit was also more vigorous when grafted on Orejona. Based on DNA content and anatomical analyses, in vitro yellow dragon fruit micrografting is feasible in all used rootstocks.

Abstract The use of silicon in Billbergia zebrina cultivation in vitro is an alternative for optimizing micropropagation of this important ornamental plant species. The objective of the present study was to evaluate the growth and anatomical and physiological alterations in Billbergia zebrina (Herbert) Lindley plants as a function of different sources and concentrations of silicon during in vitro cultivation and acclimatization. The experimental design was completely randomized, with a double factorial arrangement and an additional control treatment (2 x 3 + 1). The first factor was relative to calcium silicate and sodium silicate added to the Murashige & Skoog culture medium; the second factor was related to its concentrations, 0.5, 1.0, and 2.0 mg L-1. After 100 days, their growth, anatomical characteristics, level of silicon and chlorophyll content were evaluated. Growth characteristics were assessed after 60 days of acclimatization period. Plants absorbed more sodium silicate than calcium silicate. This source also stressed the plants impairing their growth, but the highest silicon absorption at 1 mg L-1 attenuated the stressful conditions. The supplementation of the culture medium with calcium silicate led to improved growth, anatomical, and physiological characteristics, which benefited the development of more resistant seedlings with better performance during acclimatization.

Abstract The jelly palm plant [Butia capitata (Martius) Beccari] is a native palm of the Cerrado biome used for many purposes in northern Minas Gerais State, Brazil. Dormancy is common in palm seeds, resulting in slow and uneven germination that may take years to complete. Modification in the growth pattern, anatomical parameters, physiological and biochemical characteristics of the plant can be verified due to changes in the light spectrum transmitted through colored shade nets used. Therefore, the objective of this study is to evaluate the effect of colored shade nets on the leaf and root anatomy of the jelly palm plant. The experiment was performed in a completely randomized design, with five treatments, ten replicates and eight plants per replicate, totaling 400 plants. Four colored photo-converter nets with 50% shading and different radiation proportions were employed: 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). The plants cultivated under direct sunlight (1000 μmol.m-2.s-1) were considered as the control group. Leaf and root anatomical analysis was performed on 10 plants per treatment. It is possible to conclude that the colored shade nets caused changes in leaf and root anatomy of the jelly palm plant (Butia capitata).

Abstract Garlic (Allium sativum L.) plays an important role in popular culture due to its dietary and medicinal uses. It is also used to produce a wide range of pharmacologically interesting molecules. Several pathogens affect garlic plants, especially Athelia (Sclerotium) rolfsii, a fungus that is widespread and causes large economic losses. It causes direct damage to crops and leads to plant stress, which induces secondary metabolite production in plants. The use of microorganisms as biocontrol agents may induce the production of beneficial metabolites in plants that will protect it and promote resistance to pathogen attack. In addition to suppressing disease, biological control agents may have elicitor effects that could induce an increase in the production of useful bioactive secondary metabolites in plants, some of which may be of pharmacological interest. Therefore, the search for new biological control agents should also consider their potential as elicitor agents. This paper presents an analysis of the biological control of Athelia (Sclerotium) rolfsii by antagonistic microrganisms, the potential of yeasts and bacteria of the genus Bacillus for the biocontrol of phytopathogens, microrganisms influence in nutritional and bioactive compounds content of interest to the pharmaceutical industry.

Resumo: O objetivo deste trabalho foi avaliar os efeitos da temperatura e de agentes osmóticos na conservação in vitro de físalis (Physalis peruviana). Foram testadas as temperaturas de 18 e 25°C, bem como os agentes osmóticos sacarose, manitol e sorbitol. A conservação de físalis in vitro, em curto prazo, pode ser conseguida a 18°C, em meio com adição de 30 g L-1 de sacarose.

Abstract: The objective of this work was to evaluate the effects of temperature and osmotic agents on the in vitro conservation of Cape gooseberry (Physalis peruviana). Temperatures at 18 and 25°C, as well as the osmotic agents sucrose, mannitol, and sorbitol were tested. A short-term in vitro conservation of Cape gooseberry can be achieved at 18°C, using 30 g L-1 sucrose.