In this article we will discuss about the construction and distribution of mechanical cells in plants. The principle regarding the construction of mechanical tissue is to obtain maximum mechanical rigidity and elasticity with minimum expenditure of materials. This principle is observed in roots, stems, fruit stalks, branches etc., but the arrangement of mechanical cells varies greatly in them. The organs [...]
In this article we will discuss about the evolution of stele in a plant. Stele (= Greek word meaning a column) can be defined as the unit of vascular system that is made up of xylem, phloem, interfascicular tissues, medullary rays, pericycle and pith (if present). The term stele refers to the central core of plant axis and is restricted [...]
In this article we will discuss about the evolution of stelar forms in vascular plants. The well known genus Rhynia represents the simplest kind of vascular plant. It is rootless, leafless and the axis is dichotomously branched. A stele runs through the centre of stem. The cells in the very centre of stele consist of tracheids only and this xylem [...]