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Aerenchyma in stem cross section of a typical wetland plant. Aerenchyma or aeriferous parenchyma [1] or lacunae, is a modification of the parenchyma to form a spongy tissue that creates spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and the root. [2]
This tissue system is present between the dermal tissue and forms the main bulk of the plant body. Parenchyma cells have thin primary walls and usually remain alive after they become mature. Parenchyma forms the "filler" tissue in the soft parts of plants, and is usually present in cortex , pericycle , pith , and medullary rays in primary stem ...
It was written around 350 BC. The whole work is roughly a study in animal anatomy and physiology; it aims to provide a scientific understanding of the parts (organs, tissues, fluids, etc.) of animals and asks whether these parts were designed or arose by chance.
Most scales are lamellar (blade like) and attached with a pedicel, while other forms may be hair like or specialised as secondary sexual characteristics. The lumen, or surface of the lamella, has a complex structure. It gives colour either due to the pigments contained within it or through its three-dimensional structure. [8]
Sclereids in a diffuse pattern are dispersed throughout the leaf tissue, and sclereids in a terminal pattern are concentrated about the tips of leaf veins. Sclereid formations in leaves include the branched sclereids of Trochodendron , the columnar sclereids of Hakea , and the hair-like trichosclereids that branch into air chambers within the ...
Parenchyma (/ p ə ˈ r ɛ ŋ k ɪ m ə /) [1] [2] is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology, it is the tissue that fills the interior of flatworms. In botany, it is some layers in the cross-section of the leaf. [3]
Animal tissues are grouped into four basic types: connective, muscle, nervous, and epithelial. [4] Collections of tissues joined in units to serve a common function compose organs. While most animals can generally be considered to contain the four tissue types, the manifestation of these tissues can differ depending on the type of organism.
In the anatomy of some taxa, such as many Cicadomorpha, the front of the head is fairly clearly distinguished and tends to be broad and sub-vertical; that median area commonly is taken to be the frons. [9] The clypeus is a sclerite between the face and labrum, which is dorsally separated from the frons by the frontoclypeal suture in primitive ...