-Addition of Silicon (Si) to culture media has been shown to improve the development of seedlings grown in vitro, and to reduce losses during the acclimatization phase. The objective of this study was to evaluate the in vitro growth of Cattleya forbesii (Orchidaceae) in MS medium containing five different concentrations of SiO 2 (0.0, 0.5, 1.0, 1.5, and 2.0 g·L −1 ). At day 200, the following variables were measured: number of roots, average length of the root system, leaf area, number of leaves and shoots, shoot height, fresh and dry masses of roots and shoots, water content of roots and shoots, and pH of the culture medium. Most variables decreased as the concentration of Si increased, reducing the in vitro vegetative growth of C. forbesii. Accumulation of Si in leaf tissues was detected by scanning electron microscopy, confirming uptake by plants.The Si source and concentrations tested showed no beneficial effect on in vitro growth of C. forbesii.Keywords: Micropropagation, Culture medium, Amorphous silica. SILÍCIO NO DESENVOLVIMENTO IN VITRO DA ORQUÍDEA Cattleya forbesiiRESUMO -A adição de silício (Si) aos meios de cultura tem apontado melhor desenvolvimento das plântulas cultivadas in vitro e redução das perdas durante a fase de aclimatização. Objetivou-se avaliar cinco concentrações de SiO 2 (0,0; 0,5; 1,0; 1,5 e 2,0 g·L −1 ) em meio de cultura MS sobre o crescimento in vitro da orquídea Cattleya forbesii. Aos 200 dias, avaliou-se as variáveis: número de raízes, comprimento médio do sistema radicular, área foliar, número de folhas e de brotos, altura da parte aérea, massa fresca e seca de raízes e de parte aérea, conteúdo de água das raízes e da parte aérea, e pH final dos meios de cultura. Para a maioria das variáveis avaliadas observou-se decréscimo em função do aumento da concentração de Si, reduzindo o desenvolvimento vegetativo in vitro da C. forbesii. Além disso, detectou-se acúmulo de Si nos tecidos foliares por meio da microscopia eletrônica de varredura, confirmando a absorção deste pelas plântulas. Para o crescimento in vitro da espécie estudada, a fonte e concentrações de Si testadas, não apresentaram efeito benéfico.Palavras-chave: Micropropagação. Meio de cultura. Sílica amorfa. ________________ *

ResumoO silício é considerado um elemento benéfico às plantas, podendo trazer incrementos na produtividade e sanidade de diversas culturas. Nos vegetais, acumula-se principalmente nas áreas de máxima transpiração. Este trabalho teve por objetivo comparar o acúmulo de silício nas folhas bandeira de diferentes genótipos de trigo (Triticum aestivum L.), com o auxílio da Microscopia Eletrônica de Varredura (MEV). O experimento foi conduzido a campo, durante o ano agrícola de 2010, aonde foram utilizados oito genótipos de trigo (cultivares BRS 208, IPR 85, BRS Pardela, BRS 210, IPR 130, CD 104, BRS 220 e a linhagem WT 07106). Aos três meses após a semeadura, retiraram-se amostras das folhas para a análise de silício em MEV e espectroscopia de energia dispersiva de raios-X (EDS). Todos os genótipos avaliados acumularam corpos silicosos em suas epidermes foliares, sendo que esses corpos apresentaram formato arredondado e deposição diferenciada entre os diversos genótipos. Palavras-chave: Silício, Triticum aestivum, corpos silicosos, microscopia eletrônica de varredura, espectroscopia de energia dispersiva de raios-X AbstractSilicon is considered a beneficial element to plants and may increase productivity and health of many crops. In plants, silicon accumulates mainly in the areas of maximum transpiration. This study aimed to investigate and compare silicon accumulation in flag leaves of different genotypes of wheat (Triticum aestivum) with the aid of scanning electron microscopy (SEM). The experiment was conducted in the field during the growing season 2010, eight wheat genotypes (BRS 208, RPI 85, BRS Pardela, BRS 210, RPI 130, CD 104, BRS 220 and WT 07106 lineage) were used. Three months after sowing, the samples were collected from the leaves to perform the silicon analysis by SEM and energy dispersive X-ray (EDS). All genotypes accumulated silica bodies in their leaf epidermis, the bodies had a rounded shape and were deposited differently from one genotype to another.

Snap beans have been widely used in organic farming as a good income source and an alternative to diversify production, with increasing use in crop rotation. This work reports the evaluation of 25 bush-type snap beans accessions for their suitability to integrate a breeding program for organic farming, as well as for their resistance to the common bacterial blight (CBB). Agronomic performance was assessed in two field experiments (September-December, 2013; April-June, 2014), in complete blocks at random, while resistance to CBB was assessed in greenhouse, in a completely randomized trial. Plants were challenged with two isolates, one from Xanthomonas axonopodis pv. phaseoli and another from X. fuscans subsp. fuscans. Accessions UEL 402, UEL 405, UEL 407, UEL 408, UEL 412, UEL 417 and UEL 420 were highly productive in both seasons (averages of 10.3, 8.7, 9.5, 9.2, 8.9, 9.3 and 9.2 t/ha, respectively), and are promising for use both as cultivars by organic farmers in the region of Londrina and also as germplasm in breeding programs for developing cultivars adapted to the region. Although all accessions were moderately susceptible to CBB, accessions UEL 407, UEL 409, UEL 411, UEL 412, UEL 424 and UEL 431 presented the lowest values for the area under CBB progress curve for both isolates.

ABSTRACT. Different plant species have different levels and locations of silicon accumulation in their tissues, and may or may not have silica bodies. Grasses usually accumulate these bodies, which may have different shapes depending on the genotype. Besides, this element can be beneficial to crops. The present study aimed to examine the forms and locations of silicon accumulation, as well as silicon content, in flag leaves of corn (Zea mays L.). This was a field experiment with two cultivars of corn: Coodetec 384 and Pioneer BG7065H. Four months after sowing, the flag leaves of the corn cultivars were obtained for determination of the silicon content of leaf tissue with the use of plasma atomic emission spectrometry, as well as examination of the different forms and locations of silicon accumulation using scanning electron microscopy and energy dispersive X-ray spectroscopy. The two cultivars were found to accumulate foliar silicon, primarily at the base of the trichomes and on the venation. Also, silica bodies in the shape of four-leaf clovers and dumbbells were detected, and the cultivar 1691 Accumulation of silicon in corn leaves ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 13 (1): 1690-1696 (2014) Coodetec 384 showed a silicon content in leaf tissue 26% higher than that of Pioneer BG7065H.

The snap bean (Phaseolus vulgaris L.) is an economically important legume worldwide due to its good nutritional quality, being considered as a source of protein, fibre, vitamins and minerals. Furthermore, snap beans present high phenolic compound levels and antioxidant activity, factors that contribute in the prevention of the oxidation effects by free radicals. Hence, the present study characterized five snap bean genotypes (UEL 1, UEL 2, UEL 405, UEL 415 and Alessa) with respect to their amino acid concentrations, total phenolic compound contents and antioxidant activities. The amino acid analysis indicated that UEL 415 showed the highest glutamic acid content (12.9 g / 100 g) and UEL 2 the highest histidine content (2.27 g / 100 g). However, only the UEL 1 genotype showed the highest total phenolic compound content (0.492 mg GAE / 100 g) and highest antioxidant activity according to DPPH• radical scavenging (64.71%). The UEL 1, UEL 2 and UEL 415 genotypes presented desirable chemical characteristics for genetic improvement programmes and their commercial exploitation by food industries.

ABSTRACT. The present study aimed to estimate and characterize the genetic divergence between determinate and indeterminate snap bean accessions from the Universidade Estadual de Londrina (UEL) germplasm bank based on amplified fragment length polymorphism (AFLP) markers. A total of 40 and 32 accessions with determinate and indeterminate growth habits, respectively, were characterized for this purpose. Seven combinations of primers corresponding to EcoR1 and Mse1 were tested for the AFLP analysis, and the combinations E-AAG/M-CTC, E-ACT/M-CTT and E-ACC/M-CTT were selected. These selective AFLP combinations revealed 485 informative loci in total, and the combination E-ACC/M-CTT detected the greatest number of informative loci (49%). The analysis of dissimilarity frequency distribution showed that the distribution was uniform, ranging from 0.1285 to 0.7310 with a mean of 0.4801, and the accessions with indeterminate growth habits exhibited greater variability than the accessions with determinate growth habits. The clustering UPGMA, PCoA and Bayesian analyses showed the formation of two large clusters, wherein there is a possible association between snap bean growth habit and gene pool. The determinate accessions may be more closely associated with the Andean gene pool, while the indeterminate ones may be associated with the Mesoamerican gene pool. The Bayesian analysis showed accessions intermediate to both groups, suggesting introgression between the Andean and Mesoamerican gene pools.Keywords: Phaseolus vulgaris L., molecular markers, amplified fragment length polymorphism, gene bank.Análise de AFLP na diversidade genética em acessos de feijão-de-vagem de hábito determinado e indeterminado RESUMO. O presente trabalho teve como objetivo estimar e caracterizar a divergência genética entre acessos de feijão-de-vagem determinado e indeterminado do banco de germoplasma da UEL com base em marcadores AFLP. Para tanto foram caracterizados 40 e 32 acessos de hábito determinado e indeterminado, respectivamente. Para análise do AFLP, sete combinações de primers EcoR1 e Mse1 foram testadas, sendo selecionadas as combinações E-AAG/M-CTC, E-ACT/M-CTT, E-ACC/M-CTT. Essas combinações de iniciador/enzima revelaram um total de 485 locos informativos, sendo a combinação E-ACC/M-CTT a que detectou o maior número de locos informativos (49%). A análise da distribuição das frequências da dissimilaridade revelou que a distribuição foi uniforme variando de 0.1285 a 0.7310 com média de 0.4801, com os acessos de hábito indeterminado apresentando uma maior variabilidade quando comparado com os de hábito determinado. Pelas análises de agrupamento UPGMA, PCoA e Bayesiana verificou-se a formação de dois grandes grupos, para os quais sugere-se uma possível predominância do hábito de crescimento do feijão-de-vagem quanto ao pool gênico. Os determinados podem estar mais associados ao pool gênico Andino, enquanto o indeterminado ao pool gênico Mesoamericano. Pela análise Bayesiana, verificou-se acessos intermediário aos dois grupos sugerindo-se u...

The objective of this work was to evaluate the application of calcium silicate in the yield and nutritional state of lettuce plants and to verify forms of foliar Si accumulation, using scanning electron microscopy (SEM), at the Universidade Estadual de Londrina greenhouse. Experimental design was randomized, in a 4x2 factorial scheme with four replications, including four lettuce cultivars (Lucy Brown, Vanda, Elisa and Romaine) and two doses of silicate calcium (0 and 4000 kg ha-1). Calcium silicate application showed no differences for yield, growth and nutritional state in the assayed plants. Differences among cultivars were probably due to genotypic traits. The Romaine cultivar showed greater aerial part fresh matter, aerial dry matter and height. Lucy Brown and Romaine cultivars showed greater N content. ‘Lucy Brown’, ‘Romaine’ and ‘Vanda’ showed greater K content. The Elisa cultivar showed the greatest Ca, Mg and Zn contents. The Elisa and Romaine cultivars showed the greatest Si content. The scanning electron micrograph revealed that there was no development of siliceous bodies in the lettuce, and Si foliar accumulation occurred sparsely.

This study aimed to establish the anatomical characteristics, and to determine the density, size and distribution of stomata in the abaxial surface of leaves of different cassava genotypes. The apical, middle and basal portions of fully expanded leaves of genotypes Baianinha, Caapora, Fécula Branca, IAC 12, IAC 13, IAC 14, IAC 15, IAC 576, IAC 90 and IAPAR União were analyzed. The design was completely randomized with a 3 by 3 factorial arrangement and three replications, and the data were analyzed by Anova and Scott-Knott test. The parameters evaluated concerned the number, polar and equatorial diameters of stomata and calculations of density and stomatal functionality. Significant interaction was found among the different genotypes and the distribution and size of stomata in the different parts of the leave, being more frequent in leaf apices. The genotypes Baianinha, Caapora, IAC 576 and IAPAR União characterized the group with the highest stomatal density, while the genotype IAC 90 showed the lowest density and the largest polar diameter, regardless of the location of the stomata. In the analyzed leaves, the lowest polar diameter was detected in the genotypes Baianinha, Caapora, IAC 14 and IAPAR União, while the largest equatorial diameter was found in IAPAR União. In all genotypes, functionality was inversely proportional to stomatal density, with a negative correlation between stomatal density and the polar diameter of stomata.