Contrasting leaf intercellular space development in sorghum and maize modulates different tolerance capacity to water limitation.

The objective of this study was to evaluate the relationship between intercellular spaces and leaf gas exchange and the effect of total intercellular space on the growth of maize and sorghum under water restriction. The experiments were conducted in a greenhouse in a 2 × 3 factorial arrangement (two plant types and three water conditions: field capacity (FC = 100%), 75%FC, and 50%FC) with 10 replicates. The lack of water was a limiting factor for maize because it showed reductions in leaf area, leaf thickness, biomass, and gas exchange parameters, while sorghum remained unchanged, maintaining its water-use efficiency. This maintenance was correlated with the growth of intercellular spaces in sorghum leaves because the increased internal volume led to better CO2 control and prevented excessive water loss under drought stress. In addition, sorghum had more stomata than maize. These characteristics contributed to the drought tolerance of sorghum, while maize could not make the same adjustments. Therefore, changes in intercellular spaces promoted adjustments to avoid water loss and may have improved CO2 diffusion, characteristics that are important for drought-tolerant plants.

Root anatomy, growth, and development of Typha domingensis Pers. (Typhaceae) and their relationship with cadmium absorption, accumulation, and tolerance.

Typha domingensis Pers. is a plant that grows in marshy environments, where cadmium (Cd) accumulates. The root is the first organ that comes into contact with the metal. The aim of this study was to evaluate the effect of Cd on the roots of T. domingensis. The experiment was conducted in a greenhouse using different Cd concentrations: (1) 0 µM (control), (2) 10 µM, and (3) 50 µM, with 10 replicates for 90 days. The plants were placed in plastic containers containing 5 L of nutrient solution modified with the different Cd concentrations. At the end of the experiment, the roots were measured, sampled, fixed, and subjected to usual plant microtechniques. The slides were observed and photographed under light microscopy and analyzed in ImageJ software. To measure Cd absorption, atomic-absorption spectrometry was used. The data were subjected to analysis of variance and comparison of means by the Scott-Knott test at P < 0.05. When exposed to 50 µM of Cd, the roots accumulated 99.35% of the Cd. At this concentration, there was a reduction in the exodermis but there was an increase in the diameter of the cortical cells and in the proportion of aerenchyma in the cortex. There was an increase in the root cap, which guaranteed the protection of the primary meristems. Therefore, T. domingensis adjusts its root anatomy improving the Cd tolerance and shows potential for phytoremediation purposes.

Stomatal cavity modulates the gas exchange of Sorghum bicolor (L.) Moench. grown under different water levels.

This work aimed to evaluate the effects of lower water levels on leaf intercellular spaces and to assess their relations with the gas exchange, anatomy, and growth of Sorghum bicolor. Experiments were conducted in a greenhouse, in which plants were subjected to three water conditions (ten replicates, n = 30): well-irrigated, decreased irrigation, and limited irrigation. Lower water levels had no significant effect on the growth of S. bicolor but increased the biomass of the roots. Moreover, the number of leaves, leaf area, and leaf size as well as the chlorophyll content were not affected by lower water levels, and no significant changes were detected for whole plant photosynthesis, transpiration, or stomatal conductance. The water content of the plants and the water potential remained unchanged. However, compared with other treatments, the decreased irrigation decreased water loss and increased the water retention. Lower water levels increased the intercellular CO2 percentage, mesophyll area, and proportion of stomatal cavities and promoted minor changes in leaf tissue and stomatal traits. The increased stomatal cavities provided higher CO2 uptake and prevented excessive water loss. Thus, modifications to the intercellular spaces promoted conditions to avoid excessive water loss while concurrently improving CO2 uptake, which are important traits for drought-tolerant plants.

Programa de melhoria do acesso e da qualidade da atenção básica sob a ótica médica / Program for access and quality improvement in primary care from a medical perspective / Programa de mejora del acceso y la calidad de la atención básica bajo la óptica médica

Objetivo: compreender a concepção sobre o Programa de Melhoria do Acesso e da Qualidade da Atenção Básica (PMAQ-AB) sob a ótica dos médicos atuantes nas equipes de Saúde da Família. Método: Pesquisa qualitativa, realizada com 14 médicos através de entrevistas com roteiro semiestruturado. Os dados foram analisados utilizando-se a técnica de análise de conteúdo. Resultados: Elaboraram-se três categorias temáticas: A concepção médica sobre o PMAQ-AB: visões que se contrapõem; A face positiva do PMAQ-AB; PMAQ-AB e as dificuldades vivenciadas pelos médicos. Conclusão: Fazem-se necessários programas de educação permanente no tocante às políticas de saúde de forma a incorporá-las com maior efetividade visando à qualidade nas práticas dos serviços de saúde. Ressalta-se a necessidade de investimentos na estrutura física e recursos materiais que são apontados como aspectos limitadores para a atuação dos profissionais (AU).

Objective: To understand the meaning of the program for improving access and quality of primary care from the perspective of physicians working in family health teams. Methods: Qualitative research, performed with 14 physicians through interviews with a semi-structured script. Data were analyzed using the content analysis technique. Results: Three thematic categories were elaborated: The medical conception of PMAQ-AB: opposing views; the positive face of PMAQ-AB; PMAQ-AB and the difficulties experienced by doctors. Conclusion: Permanent education programs are necessary in relation to health policies in order to incorporate them with greater effectiveness aiming at quality in health services practices (AU).

Objetivo: Entender el significado del programa para mejorar el acceso y la calidad de la atención primaria desde la perspectiva de los médicos que trabajan en equipos de salud familiar. Métodos: Investigación cualitativa, realizada con 14 médicos a través de entrevistas con un guión semiestructurado. Los datos se analizaron utilizando la técnica de análisis de contenido. Resultados: Se elaboraron tres categorías temáticas: La concepción médica de PMAQ-AB: puntos de vista opuestos; La cara positiva de PMAQ-AB; PMAQ-AB y las dificultades experimentadas por los médicos. Conclusión: Los programas de educación permanente son necesarios en relación con las políticas de salud con el fin de incorporarlos con mayor eficacia con el objetivo de la calidad en las prácticas de servicios de salud (AU).

Physically cross-linked aerogels based on germinated and non-germinated wheat starch and PEO for application as water absorbers for food packaging.

The objective of this study was to generate and characterize physically cross-linked aerogels by using germinated and non-germinated wheat starch, with and without the addition of poly (ethylene oxide) (PEO). Aerogels were produced by gelatinization of starch (10% w/v, in distilled water) at 90 °C, followed by multiple freeze/thaw cycles. For the aerogel produced using starch and PEO, a solution of 6% PEO (0.6 g of PEO/10 mL of distilled water) was added to the dispersion. The thermal properties, infrared spectra, relative crystallinity, morphology, water absorption properties, and texture profile of the aerogels were evaluated. After immersion in water for 24 h, the aerogels exhibited high degradation temperature, water absorption capacity, and physical integrity. Aerogels produced using the germinated wheat starch were much more integrated structurally compared to the aerogels produced using the non-germinated wheat starch. Wheat germination did not have any impact on the textural parameters of the aerogels. However, addition of PEO increased the water absorption capacity and reduced the hardness and cohesion of the resulting aerogels. Due to the high water absorption potential, the aerogel produced in this study can serve as an absorbent matrix in food packaging.

Electrospinning of native and anionic corn starch fibers with different amylose contents.

Through starch phosphorylation and solution aging treatments, the aim of this work was to produce electrospun fibers derived from native and anionic (modified with sodium tripolyphosphate) corn starches with amylose contents of <70% (w/w). The fibers of native and anionic corn starches (regular amylose and high amylose Hylon V/Hylon VII) were prepared by electrospinning of starch solutions dissolved in aqueous 75% formic acid (v/v) solvent. The effects of the aging (24, 48, and 72 h) on the rheology and electrical conductivity of the starch solutions, as well as the material properties (size distribution, morphology, and infrared spectrum) of the resulting electrospun fibers, were evaluated. Fibers produced from Hylon VII and Hylon V starches showed homogeneous morphologies, whereas the fibers from regular corn starches exhibited droplets and had heterogeneous morphologies, with diameter varied from 70 to 264 nm. Both native and anionic corn starches, with amylose contents of <70% (w/w), produced smooth continuous fibers. The electrospun corn starch fibers potentially can be used as carriers for the encapsulation of active components in food and packaging applications.

Characteristics of starch from different bean genotypes and its effect on biodegradable films.

BACKGROUND: Starches from four common bean genotypes were characterized and used in the production of biodegradable films. Starches were characterized by their swelling power, solubility, amylose content, granule morphology, relative crystallinity, thermal and pasting properties, and susceptibility to α-amylase hydrolysis. Films were characterized according to their morphology, mechanical and water vapor barrier properties, whiteness and opacity. RESULT: Depending on the common bean genotype, a great variation on starch properties was found, which, in turn, clearly impacted on the characteristics of the starch-based films. Starches from BRS Pitanga and BRS Pérola genotypes exhibited the highest amylose content and the lowest swelling capabilities. Bean starch from the IPR Uirapuru genotype presented granules with an irregular surface and shape. Starches from IPR Uirapuru and BRS Estilo genotypes provided well-structured biodegradable films, without the occurrence of fissures or cracks. Moreover, starch films containing starch from BRS Estilo genotype exhibited the highest flexibility, permeability and solubility. CONCLUSION: The morphological, mechanical and water vapor barrier properties of films elaborated with common bean starch vary greatly as a function of the bean genotype used for starch production. © 2018 Society of Chemical Industry.

Cellulose nanocrystals from rice and oat husks and their application in aerogels for food packaging.

This study describes the valorization of rice and oat husks by obtaining cellulose nanocrystals for the production of aerogels for food packaging applications. Commercial cellulose was used as a control sample. Nanocrystals from cellulose were obtained by enzymatic hydrolysis and mechanical treatment at high pressure. The morphology, particle size, functional groups, crystallinity, and thermal properties of the cellulose nanocrystals were analyzed. The morphology, functional groups, crystallinity, water absorption capability, and zeta potential of aerogels were also analyzed. Cellulose nanocrystals show different structural properties and crystallinity depending on the source of the cellulose. The average diameter of the nanocrystals varied from 16.0 to 28.8 nm. The aerogels prepared with cellulose nanocrystals showed a porous and uniform structure with a water absorption capacity between 264.2% and 402.8% at 25 °C. The aerogel of oat cellulose nanocrystals showed a larger pore size than that of eucalyptus cellulose nanocrystals, and this may have influenced the lowest water absorption capacity of the aerogels of eucalyptus cellulose nanocrystals. These results show that agroindustrial residues have promising applications in various industrial fields and could be used as aerogel absorbers of water in food packaging.

Leaf ontogeny of Schinus molle L. plants under cadmium contamination: the meristematic origin of leaf structural changes.

Previous works show the development of thicker leaves on tolerant plants growing under cadmium (Cd2+) contamination. The aim of this study was to evaluate the Cd2+ effects on the leaf meristems of the tolerant species Schinus molle. Plants were grown in nutrient solution containing 0, 10, and 50 µM of Cd2+. Anatomical analysis was performed on leaf primordia sampled at regular time intervals. Under the lowest Cd2+ level (10 µM), increased ground meristem thickness, diameter of the cells, cell elongation rate, and leaf dry mass were found. However, 50 µM of Cd2+ reduced all these variables. In addition, the ground meristem cells became larger when exposed to any Cd2+ level. The epidermis, palisade parenchyma, and vascular tissues developed earlier in Cd2+-exposed leaves. The modifications found on the ground meristem may be related to the development of thicker leaves on S. molle plants exposed to low Cd2+ levels. Furthermore, older leaves showed higher Cd2+ content when compared to the younger ones, preventing the Cd2+ toxicity to these leaves. Thus, low Cd2+ concentrations change the ground meristem structure and function reflecting on the development of thicker and enhanced leaves.

Cellulose fibers extracted from rice and oat husks and their application in hydrogel.

The commercial cellulose fibers and cellulose fibers extracted from rice and oat husks were analyzed by chemical composition, morphology, functional groups, crystallinity and thermal properties. The cellulose fibers from rice and oat husks were used to produce hydrogels with poly (vinyl alcohol). The fibers presented different structural, crystallinity, and thermal properties, depending on the cellulose source. The hydrogel from rice cellulose fibers had a network structure with a similar agglomeration sponge, with more homogeneous pores compared to the hydrogel from oat cellulose fibers. The hydrogels prepared from the cellulose extracted from rice and oat husks showed water absorption capacity of 141.6-392.1% and high opacity. The highest water absorption capacity and maximum stress the compression were presented by rice cellulose hydrogel at 25°C. These results show that the use of agro-industrial residues is promising for the biomaterial field, especially in the preparation of hydrogels.