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’.

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 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.