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Most commonly anthers are two-lobed (each lobe is termed a locule) and are attached to the filament either at the base or in the middle area of the anther. The sterile tissue between the lobes is called the connective, an extension of the filament containing conducting strands. It can be seen as an extension on the dorsal side of the anther.
Most anthers are formed on the apex of a filament. An anther and its filament together form a typical (or filantherous) stamen, part of the male floral organ. The typical anther is bilocular, i.e. it consists of two thecae. Each theca contains two microsporangia, also known as pollen sacs.
Bacterial morphological plasticity refers to changes in the shape and size that bacterial cells undergo when they encounter stressful environments. Although bacteria have evolved complex molecular strategies to maintain their shape, many are able to alter their shape as a survival strategy in response to protist predators, antibiotics, the immune response, and other threats.
A microspore undergoes mitosis and cytokinesis in order to produce two separate cells, the generative cell and the tube cell. These two cells in addition to the spore wall make up an immature pollen grain. As the male gametophyte matures, the generative cell passes into the tube cell, and the generative cell undergoes mitosis, producing two ...
The cells of endothecium have fibrous thickenings. One to three middle layers. Cells of these layers generally disintegrate in the mature anther; A single layer of tapetum. The tapetal cells may be uni-, bi- or multinucleate and possess dense cytoplasm. The cells of the primary sporogenous layer divide further and give rise to diploid ...
(of a compound leaf) Having precisely two leaflet s, usually in a symmetrical pair, e.g. a leaf of Colophospermum mopane. Compare jugate lobed leaf, e.g. most species of Bauhinia. bifusiform Fusiform with a pinch in the middle. bilabiate Having two lips, e.g. the form of the petal s in many irregular flowers. bilateral 1.
Two main tapetum types are recognised, secretory (glandular) and periplasmodial (amoeboid). In the secretory type, a layer of tapetal cells remains around the anther locule . In contrast, the tapetal cell walls dissolve in the periplasmodial type, and their protoplasts fuse to form a multinucleate periplasmodium.
The transition from chloronema to caulonema cells along a filament is gradual. [4] Later in the development of the plant, caulonema cells can form new branches of chloronema cell type, called secondary chloronema. [3] The protonema cells grow apically, meaning that the growth of the filament happens by the division of the cells at the tip of ...