Defintion of Root

Root is the bottom of the plant that usually develops below ground level. There are some plants have roots that grow in the air. The shape and structure of the highly diverse roots. This situation is related to the root function as a store of food reserves, succulent roots, the roots of breath, and hair roots. If dicotyledonous plant seeds germinate, the bottom will come out roots. The root is also called the radicle which will penetrate the soil. This root is called the primary root. After some period of roots will form roots branches called secondary roots. Anatomy of the roots can be observed by means of transversely cutting the roots. The sequence from the outside to the inside, root anatomical structure composed of epidermis, cortex, endodermis, and a central cylinder (stele).



a. The epidermis


Root epidermal cells, thin-walled and usually do not have cuticle. The most distinctive characteristic of the root epidermis is the formation of root hairs. Hair root is the organ that is very suitable for making water and mineral salts.


b. Cortex


In the next part in the epidermis are composed of cortical parenchyma tissue that acts to store food reserves. Relatively spherical shape of the cell cortex (isodiametris) with clear intercellular space. Water and mineral salts from the roots will pass through the cortical cells through intercellular space. This event is called extra transport vasikuler in apoplast. Cortical cells contain food reserves in the form of starch and other substances. Part of the cortex are endothermic network consisting of a single layer of cells with a thick cell wall containing wax. The endothermic located between the cylinder center with the cortex.


c. Endodermis


On the walls of the cells are plasmodesmata. Endodermis is a network that can regulate the importation of water into the transport network are located in the central cylinder. Among the phloem to xylem cambium interfasis are involved in the formation of the fingers pith (parenchyma tissue that connects between the pith and bark). The pith parenchyma tissue located at the center of the root or stem. At the endodermis cell wall associated with another endodermis cell, there is a layer of cork called kaspari tape. The endothermic who do not have a band called cell kaspari successor.


d. Stele (cylinder center)


Endodermis contained inside the cylinder area which occupies the center of the central part of the root. The primary vascular tissue surrounded by a collection of cells called perisikel adjoining tissue. This network is the parenchyma. Perisikel are actively dividing (meristematis), such as the cambium so called perikambium, and capable of forming root branch (secondary roots). On the inside there perisikel secondary network, file phloem vessels, and xylem. This file is a secondary network which is surrounded by parenchymal tissue. Phloem and cambium secondary xylem formed by fascists and lead to increased width of the trunk diameter. Fascist cambium is the boundary between the bark with wood.

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