BIOL-1507EL Lecture Notes - Lecture 9: Tracheid, Succulent Plant, Ligule
27 Jun 2018
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Biology 2 - Day 9 2017.02.06.
Cross section of root in primary growth
-Epidermis
-Including root hairs, a single layer of cells covering the roots
-Water and minerals absorbed by plants, through the epidermis
-The root hairs greatly increase the surface area for absorption
-Cortex
-The region between the epidermis and the vascular cylinder
-The ground tissue of the cortex, mostly parenchyma, which function is to be
storage
-In some species the cortex may include collenchyma, mostly below the epidermis
-Endodermis
-The inner most layer of the cortex, endodermal cells are with suberin band
-Pericycle
-Beneath the endodermis there is a layer of cells, from which a lateral root will
develop
-In most docot roots, the stele, or the vascular cylinder, form a solid core of xylem
and phloem
-The xylem radiates from the centre with the phloem developing in the wedges
between the spokes
-In many monocots, roots the vascular tissue consists of central core of parenchyma
(pith) is surrounded by alternating rings of xylem and phloem
-For example, the corn root
Tissue Organization of the Stem (in Primary Growth)
-The epidermis will cover the stem as a part of the dermal tissue
-In gymnosperm and most eudicots stem, the vascular tissue consists of vascular
bundles arranged in a ring
-VB = vascular bundle, X= xylem, P= phloem
-The xylem faces the pith, while the phloem faces the cortex
-The ground tissue between the epidermis and vascular bundle forms the cortex,
which mostly consists of parenchyma in some species may include collenchyma to
give support
-in monocot plants the vascular bundles are scattered throughout the ground tissue,
thus we cannot specify the cortex and the pith
The Vascular Cambium, and Core Cambium and Secondary Vascular Tissue
(Secondary growth)
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Document Summary
Including root hairs, a single layer of cells covering the roots. Water and minerals absorbed by plants, through the epidermis. The root hairs greatly increase the surface area for absorption. The region between the epidermis and the vascular cylinder. The ground tissue of the cortex, mostly parenchyma, which function is to be. In some species the cortex may include collenchyma, mostly below the epidermis. The inner most layer of the cortex, endodermal cells are with suberin band. Beneath the endodermis there is a layer of cells, from which a lateral root will develop. In most docot roots, the stele, or the vascular cylinder, form a solid core of xylem and phloem. The xylem radiates from the centre with the phloem developing in the wedges between the spokes. In many monocots, roots the vascular tissue consists of central core of parenchyma (pith) is surrounded by alternating rings of xylem and phloem. Tissue organization of the stem (in primary growth)
