There are three zones within the onion root tip, the meristematic zone, the zone of elongation, and the zone of maturation, all of which represent a different zone of the cells' lives, with cell division occurring actively in the meristematic zone. When a cell is ready to divide, its DNA becomes visible due to higher order structuring that starts with DNA binding to histones. Through tetrazoliu...

To control organ shape, plant cells expand differentially. The organization of the cellulose microfibrils in the cell wall is a key determinant of differential expansion. Mutations in the COBRA (COB) gene of Arabidopsis, known to affect the orientation of cell expansion in the root, are reported here to reduce the amount of crystalline cellulose in cell walls in the root growth zone. The COB ge...

PURPOSE To assess whether macular Bruch´s membrane gets lengthened in axial myopia. METHODS Using the enhanced depth imaging mode of spectral-domain optical coherence tomography and examining a subgroup of participants of the population-based cross-sectional Beijing Eye Study, we measured the length of Bruch´s membrane ("MacBMLength") from the fovea to the temporal edge of parapapillary gamma...

The epidermis is often considered to be the growthlimiting cell layer in young, growing herbaceous plants (Niklas, 1992). In his classic work, Green (1980) elaborated this idea further for organ development, and attributed a crucial role to the orientation of cellulose fibrils as indicator of mechanical properties. A factual proof for a relation between the mean cellulose orientation and mechan...

Previous work on the adaptation of maize (Zea mays) primary roots to water deficit showed that cell elongation is maintained preferentially toward the apex, and that this response involves modification of cell wall extension properties. To gain a comprehensive understanding of how cell wall protein (CWP) composition changes in association with the differential growth responses to water deficit ...

BACKGROUND To examine histomorphometrically the parapapillary region in human eyes. METHODOLOGY/PRINCIPAL FINDINGS The histomorphometric study included 65 human globes (axial length:21-37 mm). On anterior-posterior histological sections, we measured the distance Bruch's membrane end (BME)-optic nerve margin ("Gamma zone"), BME-retinal pigment epithelium (RPE) ("Beta zone"), BME-beginning of n...

How organs are shaped to specific forms is a fundamental issue in developmental biology. To address this question, we used the repetitive, periodic pattern of feather morphogenesis on chicken skin as a model. Avian feathers within a single tract extend from dome-shaped primordia to thin conical structures with a common axis of orientation. From a systems biology perspective, the process is prec...

Longitudinal zonation, as well as a simple and regular anatomy, are hallmarks of the root apex. Here we focus on one particular root-apex zone, the transition zone, which is located between the apical meristem and basal elongation region. This zone has a unique role as the determiner of cell fate and root growth; this is accomplished by means of the complex system of a polar auxin transport cir...