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 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).

Objetivou-se avaliar a influência do ambiente de cultivo e de concentrações de silicato de cálcio no crescimento in vitro de uma espécie nativa de orquídea (Brassavola perrine) e de um híbrido [(Laelia cattleya Culminant "Tuilerie" x Laelia cattleya Sons Atout Rotunda) x Brassolaelia cattleya Startifire Moon Beach]. Plântulas oriundas de sementes germinadas in vitro com aproximadamente 0,5 cm de comprimento foram inoculadas em frascos com capacidade para 250 mL contendo 60 mL de meio de cultura MS, acrescido de silicato de cálcio (0; 0,5; 1,0 e 2,0 mg L-1) em ambientes de cultivo [natural (casa de vegetação) e artificial (em sala de crescimento)], em todas as combinações possíveis. O meio de cultura teve seu pH ajustado para 5,8±0,1 e geleificado com 5,5 g L-1 de ágar antes do processo de autoclavagem a 121ºC e 1 atm por 20 minutos. Ao final de 150 dias foram realizadas avaliações biométricas e análises micromorfológicas (miscroscopia de varredura) nas plântulas. Maior crescimento foi obtido com a utilização de 2,0 mg L-1 e 1,0 mg L-1 de silicato de cálcio para o híbrido e espécie nativa, respectivamente, em sala de crescimento. As orquídeas em estudo são espécies anfiestomáticas, com estômatos do tipo tetracítico (híbrida) e anomocítico (nativa). A presença do silício na estrutura foliar proporcionou o correto desenvolvimento (ausência de deformações estruturais) de plântulas de orquídeas.

The vegetative propagation techniques using tissue culture can be a valuable tool in the production of orchid seedlings. The objective of this study was to determine the concentration of calcium silicate and light quality that provides better growth in seedlings of native orchid (Brassavola perrine) and hybrid [(Laelia cattleya Climax "Tuilerie" x Laelia cattleya Sons Atout Rotunda) x Brassolaelia cattleya Startifire Moon Beach]. Seedlings from seeds germinated in vitro with approximately 0.5 cm long were inoculated in 250 mL flasks containing 60 mL of culture medium MS, plus calcium silicate (0, 0.5, 1.0 and 2.0 mg L-1) in environments of culture [natural (a greenhouse) and artificial (in a growth room)] in all possible combinations. The culture medium had its pH adjusted to 5.8 ± 0.1 and solidified with 5.5 g L-1 of agar before autoclaving at 121º C and 1 atm for 20 minutes. After 150 days biometrics and ultrastructural analysis (scanning microscopy) were carried out. Greater growth of seedlings was obtained with the use of 2.0 mg L-1 and 1.0 mg L-1 of calcium silicate for hybrid and native species, respectively. The orchid species in study are anfistomatic with the type tetracytic (hybrid) and anomocytic (native) stomata. The presence of silicon in the leaf structure provided correct development (absence of structural deformations) of seedlings of orchids.