Xyloglucan endotransglucosylase and cell wall extensibility

Transgenic tomato hypocotyls with altered levels of an XTH gene were used to study how XET activity could affect the hypocotyl growth and cell wall extensibility. Transgenic hypocotyls showed significant over-expression (line 13) or co-suppression (line 33) of the SlXTH1 in comparison with the wild type, with these results being correlated with the results on specific soluble XET activity, suggesting that SlXTH1 translates mainly for a soluble XET isoenzyme. A relationship between XET activity and cell wall extensibility was found, and the highest total extensibility was located in the apical hypocotyl segment of the over-expressing SlXTH1 line, where the XET-specific activity and hypocotyl growth were also highest compared with the wild line

Rice Coleoptile Growth under Water and in Air-Possible Effect of Buoyancy on Growth and Cell Walls

Maximum growth was achieved in rice coleoptiles (Oryza sativa L. cv. Sasanishiki) grown under water; they reached maximum length of 81.2 mm on day 5. The maximum length of coleoptiles grown in air or under water with air bubbling was 12.4 mm and 23.5 mm in day 5,respectively. Differences in coleoptile growth between air bubbling and air conditions, namely approximately 11 mm at day 5,could be due to buoyancy effect under water. Promoted growth under water was due to a decrease in cell wall extensibility. The decrease in cell wall extensibility could be related to the inhibition of the formation of diferulic acid-bridges among arabinoxylans in cell walls under water

A simple and versatile 2-dimensional platform to study plant germination and growth under controlled humidity

We describe a simple, inexpensive, but remarkably versatile and controlled growth environment for the observation of plant germination and seedling root growth on a flat, horizontal surface over periods of weeks. The setup provides to each plant a controlled humidity (between 56% and 91% RH), and contact with both nutrients and atmosphere. The flat and horizontal geometry of the surface supporting the roots eliminates the gravitropic bias on their development and facilitates the imaging of the entire root system. Experiments can be setup under sterile conditions and then transferred to a non-sterile environment. The system can be assembled in 1-2 minutes, costs approximately 8.78$per plant, is almost entirely reusable (0.43$ per experiment in disposables), and is easily scalable to a variety of plants. We demonstrate the performance of the system by germinating, growing, and imaging Wheat (Triticum aestivum), Corn (Zea mays), and Wisconsin Fast Plants (Brassica rapa). Germination rates were close to those expected for optimal conditions

Molecular Phylogenetic Analyses of Geographical and Ecological Speciation of Anaphalis margaritacea

departmental bulletin pape

beta-1,3 : 1,4-glucan synthase activity in rice seedlings under water

Background and Aims The metabolism of beta-1,3 : 1,4-glucan regulates the mechanical properties of cell walls, and thereby changes the elongation growth of Poaceae plants. A previous study has shown that elongation growth of rice coleoptiles under water is enhanced by increased activity of beta-1,3 : 1,4-glucan hydrolases; however, the involvement of beta-1,3 : 1,4-glucan synthase activity in elongation growth under water has not yet been clarified. Methods The beta-1,3 : 1,4-glucan synthase activity in a microsomal fraction prepared from rice seedlings grown under water was compared with that from control seedlings grown in air. The change under water in the relative expression level of CslF6, a major isoform of the beta-1,3 : 1,4-glucan synthase genes, was examined by quantitative reverse-transcriptase PCR. Key Results The level of beta-1,3 : 1,4-glucan synthase activity in submerged seedlings decreased to less than 40% of that of the control seedlings and was accompanied by a significant reduction in the amount of beta-1,3 : 1,4-glucan in the cell walls. Under water, the expression of CslF6 was reduced to less than 20% of the unsubmerged control. Bubble aeration partially restored both beta-1,3 : 1,4-glucan synthase activity and the expression of CslF6 under water, correlating with suppression of the submergence-induced elongation growth of coleoptiles. Conclusions Submergence down-regulates the expression of the CslF6 gene, leading to a decreased level of beta-1,3 : 1,4-glucan synthase activity. Together with the increased activity of beta-1,3 : 1,4-glucan hydrolases, the decreased activity of beta-1,3 : 1,4-glucan synthase contributes to the decrease in the amount of beta-1,3 : 1,4-glucan in the cell walls underwater. The suppression of beta-1,3 : 1,4-glucan synthesis under water may be mainly due to oxygen depletion.textapplication/pdfjournal articl

Mechanisms Involved in Cell Wall Remodeling in Etiolated Rice Shoots Grown Under Osmotic Stress

Life. 2025, 15 (2), 196journal articl

INCLUSÃO SOCIOAMBIENTAL EM ÁREAS DE PROTEÇÃO: UM ESTUDO DE CASO DO PARQUE FERNÃO DIAS

This article discusses the importance of Environmental Protection Areas (APAs) in the environmental management of territories, focusing on the Fernão Dias APA located in the metropolitan region of Belo Horizonte. The research aimed to highlight the benefits of applying environmental education and developing actions to enhance the sustainable use of the APA by involving the community in park activities. Methodological procedures involved a local diagnosis and the development of strategies based on this diagnosis. The diagnosis was conducted through park visits, study area analysis, and the use of a checklist to describe the landscape and environmental perception. Results indicated that the Fernão Dias APA has great potential for use and increased public participation in activities. However, obstacles such as the presence of hills that hinder access, frequent invasions, and exotic species occupying the space were identified. Therefore, mitigating and improvement measures were proposed, including educational programs, environmental education, partnerships with local producers, cultural and artistic events, interpretive trails, informative signs, volunteering, and conservation actions. Keywords: Conservation Units; Environmental Education; Sustainable Development.O artigo aborda a importância das Áreas de Proteção Ambiental (APAs) no ordenamento ambiental dos territórios, com foco na APA Fernão Dias, localizada na região metropolitana de Belo Horizonte. O objetivo da pesquisa foi destacar os benefícios da aplicação da educação ambiental e desenvolver ações para potencializar o uso sustentável da APA, envolvendo a comunidade em atividades do parque. Os procedimentos metodológicos envolveram um diagnóstico local e o desenvolvimento de estratégias com base nesse diagnóstico. O diagnóstico foi realizado através de visitas ao parque, análise da área de estudo e utilização de um checklist para descrever a paisagem e a percepção ambiental. Os resultados indicaram que a APA Fernão Dias apresenta um grande potencial de utilização e aumento do público nas atividades desenvolvidas. No entanto, foram identificados obstáculos, como a presença de morros que dificultam o acesso, invasões frequentes e espécies exóticas ocupando o espaço. Assim, medidas mitigadoras e de melhoria foram propostas, incluindo programas educacionais, educação ambiental, parcerias com produtores locais, eventos culturais e artísticos, trilhas interpretativas, placas informativas, voluntariado e ações de conservaçã

Boron Nutrition of Tobacco BY-2 Cells. V. Oxidative Damage is the Major Cause of Cell Death Induced by Boron Deprivation

Boron (B) is an essential micronutrient for vascular plants. However, it remains unclear how B deficiency leads to various metabolic disorders and cell death. To understand this mechanism, we analyzed the physiological changes in suspension-cultured tobacco (Nicotiana tabacum) BY-2 cells upon B deprivation. When 3-day-old cells were transferred to B-free medium, cell death was detectable as early as 12 h after treatment. The B-deprived cells accumulated more reactive oxygen species and lipid peroxides than control cells, and showed a slight but significant decrease in the cellular ascorbate pool. Supplementing the media with lipophilic antioxidants effectively suppressed the death of B-deprived cells, suggesting that the oxidative damage is the immediate and major cause of cell death under B deficiency. Dead cells in B-free culture exhibited a characteristic morphology with a shrunken cytoplasm, which is often seen in cells undergoing programmed cell death (PCD). However, they did not display other hallmarks of PCD such as internucleosomal DNA fragmentation, decreased ascorbate peroxidase expression and protection from death by cycloheximide. These results suggest that the death of tobacco cells induced by B deprivation is not likely to be a typical PCD

Enhanced robustness digital holographic microscopy for demanding environment of space biology

We describe an optimized digital holographic microscopy system (DHM) suitable for high-resolution visualization of living cells under conditions of altered macroscopic mechanical forces such as those that arise from changes in gravitational force. Experiments were performed on both a ground-based microgravity simulation platform known as the random positioning machine (RPM) as well as during a parabolic flight campaign (PFC). Under these conditions the DHM system proved to be robust and reliable. In addition, the stability of the system during disturbances in gravitational force was further enhanced by implementing post-processing algorithms that best exploit the intrinsic advantages of DHM for hologram autofocusing and subsequent image registration. Preliminary results obtained in the form of series of phase images point towards sensible changes of cytoarchitecture under states of altered gravity