Sugarcane (Saccharum spp.) is currently one of the most efficient crops in the production of first-generation biofuels. However, the bagasse represents an additional abundant lignocellulosic resource that has the potential to increase the ethanol production per plant. To achieve a more efficient conversion of bagasse into ethanol, a better understanding of the main factors affecting biomass recalcitrance is needed. Because several studies have shown a negative effect of lignin on saccharification yield, the characterization of lignin biosynthesis, structure, and deposition in sugarcane is an important goal. Here, we present, to our knowledge, the first systematic study of lignin deposition during sugarcane stem development, using histological, biochemical, and transcriptional data derived from two sugarcane genotypes with contrasting lignin contents. Lignin amount and composition were determined in rind (outer) and pith (inner) tissues throughout stem development. In addition, the phenolic metabolome was analyzed by ultra-highperformance liquid chromatography-mass spectrometry, which allowed the identification of 35 compounds related to the phenylpropanoid pathway and monolignol biosynthesis. Furthermore, the Sugarcane EST Database was extensively surveyed to identify lignin biosynthetic gene homologs, and the expression of all identified genes during stem development was determined by quantitative reverse transcription-polymerase chain reaction. Our data provide, to our knowledge, the first in-depth characterization of lignin biosynthesis in sugarcane and form the baseline for the rational metabolic engineering of sugarcane feedstock for bioenergy purposes.

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Colleters have functional definitions such as protection against dehydration, and pathogens and insects attack. So far this definition is intuitive and no direct proof has been provided. We compared flowers of coffee mutants (Decafitto), which exhibit minimal production and secretion of exudate by colleters, with normal plants, to provide a proof of concept that the exudate covering the flowers plays a role against dehydration and acts as an adhesive to keep the petals united until flower opening.

The genus Acrocomia (Arecaceae) is widely distributed in the Neotropics, without consensus on the number of species. The arboreal species are explored in their native countries. To subsidize better use of the observed variation in fruits of different species for product extraction, taxonomy, conservation and genetic improvement, our objective was to characterize biometrically the fruits and anatomically the mesocarp from natural populations of A. aculeata, A. intumescens and A. totai. We observed different colors of epicarp and mesocarp in A. aculeata and A. totai, while the fruits of A. intumescens were light green or yellowish. The fruits of A. aculeata showed diameter considered large (3.9-4.6 cm) and the highest dry mass (26.3-33.5 g), A. intumescens presented intermediate diameter (3.1-3.9 cm) and mass (11.5-18.8 g), and A. totai had the smallest diameter (2.2-3.0 cm) and mass (4.1-11.4 g). The morphoanatomical analysis of the mesocarp did not distinguish the three species. However, it revealed the presence of useful compounds for human consumption and with economic potential, such as oil in the parenchyma cells, mucilage, starch and phenolic compounds. We concluded that the mesocarp anatomy is not useful for taxonomy, but the biometric variation is, as well as variation within species can be applicable in conservation and genetic improvement.Keywords: biofuel, palm, plant anatomy, plant products, plant taxonomy ResumoO gênero Acrocomia (Arecaceae) é amplamente distribuído no continente americano não havendo consenso sobre o seu número de espécies, sendo as de porte arbóreo comercialmente exploradas nos países onde ocorrem. Com intuito de gerar subsídios para melhor aproveitar a variação observada nos frutos das diferentes espécies para taxonomia, conservação e melhoramento genético das espécies, o objetivo do presente estudo foi caracterizar biometricamente os frutos e anatomicamente o mesocarpo de populações naturais de A. aculeata, A. intumescens e A. totai. Foram observadas diferentes colorações de epicarpo e do mesocarpo em A. aculeata e A. totai, enquanto os frutos de A. intumescens são verde-claros ou amarelados. Os frutos de A. aculeata têm diâmetro considerado grande (3,9-4,6 cm) e de maior massa seca (26,3-33,5 g), A. intumescens apresentou diâmetro e massa intermediários dos seus frutos (3,1-3,9 cm e 11,5-18,8 g, respectivamente). A. totai apresentou os menores diâmetro e massa de frutos (2,2-3,0 cm e 4,1 -11,4 g, respectivamente). A análise morfoanatômica do mesocarpo não diferenciou as espécies do estudo. No entanto, revelou a presença de compostos úteis para consumo humano e potencial econômico dos compostos identificados, como a presença de óleo nas células do parênquima, mucilagem, amido e compostos fenólicos. Conclui-se que a anatomia do mesocarpo não é útil para taxonomia e que variação biométrica entre as espécies pode ser empregada para este fim, assim como a variação dentro das espécies pode ser útil para fins de conservação e melhoramento genético.

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The effect of additives, calcium chloride and calcium lactate (5-25 g kg −1 ), on the osmotic dehydration of guavas with sucrose solutions was studied, aiming at the structural preservation of processed fruits. The osmotic process was evaluated from the reduction in weight of the guavas, water loss and solids gain, and the samples were analyzed with respect to calcium content, texture (stress and strain at failure, relaxation time and residual stress), structure by light microscopy and sensory acceptance. Calcium salts had a strong influence on the texture and structure of the processed guavas, resulting in the maintenance of tissue structure when calcium lactate was used at concentrations up to 15 g kg −1 , and calcium chloride was used at 5 g kg −1 . The sensory acceptability of guava was related to the structural and texture results. Calcium treatments did not improve guava's sensory acceptance. Guavas treated with calcium lactate showed good sensory acceptance, presenting slight inferior scores only at concentrations above 20g kg −1 , while CaCl 2 treated guavas showed average scores statistically equal to the sucrose and calcium lactate treated fruits only at 5 g kg −1 .

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