In this article we will discuss about the aperture found in the pollen and spore wall of plants. It is a weak, preformed locus on the exine of spore and pollen through which the intra-exinous substance exits and pollen tube emerges during pollen germination. Apertures may be absent from a pollen grain or spore when they are termed as inaperturate/atreme/non-aperturate [...]
In this article we will discuss about the three main biochemical pathways of major wall component formation. The biochemical pathways are: 1. Polysaccharides 2. Protein 3. Lignin. Biochemical Pathway # 1. Polysaccharides: They are synthesized from sugar nucleotides by polysaccharide synthases (Glycosyltransferase). The monosaccharides glucose, galactose, mannose, xylose, arabinose, glucuronic acid, galacturonic acid and fucose etc. compose the wall polysaccharides. [...]
The following points highlight the three main types of vegetative shoot apex found in plants. The types are: 1. Monoplex Apex 2. Simplex Apex 3. Duplex Apex. Type # 1. Monoplex Apex: Ex. cryptogamic vascular plants. Continuing meristematic residue occurs in the superficial layer only. It may consist of more than one cell provided a common wall is present between [...]