Download
1 / 31
330 likes | 539 Views
Lecture 4. Anatomical structure of vegetative plants organ . Plan 1. Anatomical structure of root . 2. Anatomical structure of stems and rhizomes . 3 . Anatomical structure of leaves. Prepare : ass. Kernychna I. Z.
E N D
Lecture 4 Anatomical structure of vegetative plants organ. Plan 1. Anatomical structure of root. 2. Anatomical structure of stems and rhizomes. 3. Anatomical structure of leaves. Prepare: ass. Kernychna I. Z.
These organisms are composed of an underground root system and an over ground shoot system.
Monocots and dicots get their names because of the number of cotyledons present in their seeds. Monocots have one seed leaf or cotyledon while dicots have 2 seed leaves or cotyledons.BEAN seed is a dicot and a CORN seed is a monocot
There are quite a few differences between a monocot and a dicot plant. This chart displays their differences:
ROOT In vascular plants, the root is the organ of a plant body that typically lies below thesurface of the soil. Functions of roots are 1.) absorption of water and inorganic nutrients, 2.) anchoring the plant body to the ground, 3) often function in storage of food
Roots of many plants use in medicine: Cichorium intydus,of althea(Althea officinalis), dandelion(Taraxacum officinale)
Long-section of root has 4 zone: І. ZONES OF CELL DIVISION with root cap ІІ. Ellongation; ІІІ. Differentiation IV. Maturation or transition.
Zone of protection also known as the ROOT CAP: envelope that protects the root.. • Meristem: tissue at the tip of the root composed of rapidly multiplying cells. Meristem tissue is found in many areas of the plant. These are all tissues that have rapidly dividing cells for cell growth. • Elongation zone: set of cells that determine the growth of the root. This zone is where plant growth regulators, such as axis, stimulate the cells from the meristem to grow larger. • Zone of Differentiation: This is the zone where the elongated cells develop into different types of tissues. These types are:
Dermal tissue- such as epidermis that protects the plant. • Ground tissue- tissue found between the dermal and vascular tissue. • Vascular tissue- tissue that transports material. Xylem transports water and phloem transports food.
Primary structure of root • (in cross sections of differentiation) • Epidermis with roots hair • Cortex (parenchyma, endodermis with Casparian strip) • Vascular cylinder (pericycle,xylem and phloem forms radial bundle)
Monocot roots vascular bundle is polyarch, closed, and radial. In dicot roots with primary structure vascular bundle is closed, radial, and tetraarch.
In dicot roots, the xylem tissue appears like a 3-pronged or 4-pronged star
Dicot roots with secondary vascular bundle structure have opened collateral vascular bundles in stele, which are arranged in circle. Between them there are wide medullary rays which are start in primary xylem and are situated in the center of a root. Dicot roots with secondary nonbundle structure have solid ring of vascular cambium, solid zone of phloem above it and solid zone of xylem below cambium. In the center there is primary xylem. Primary medullary raysstretch from it, Secondary rays are formed by cambium.
In most plants stems are located above the soil In medicine use herbs many plants (stems with leaf, flowers).
At some woody plantsuse in medicine (snowball tree, oak-tree) primarybark (cortex)
Monocot Stem. A cross section : 1)epidermis; 2) cortex (chlorenchyma and sclerenchyma); 3) Vascular cylinder (scattered vascular bundle is closed collateral.).
Monocot stems differ from dicot stems in that they lack secondary growth • No vascular cambium nor cork cambium • Stems usually uniform in diameter • Scattered vascular bundles (not in a ring like dicot stems)
A RHIZOME is underground modification of stem, which is formed at perennially herbacеous plants for an accumulation nutritives and vegetative reproduction. Has the well formed stocking parenchyma; mechanical and vascular tissues are expressed poorly. In medicine use rhizome of sedge cane, fern, valerian and other
Rhizome of monocot has three zones: dermal, primary bark and stele in cross section. Dermal tissue is epidermis. Primary bark consists of oval crumbly cells of ground parenchyma, cells of endodermis is horseshoe-like and endodermis is doubled (it is a diagnostic feature of lily of the valley). There are two types of vascular bundles in stele: closed collateral (near pericycle) and concentric centerophloem, which are chaotically arranged in parenchyma. Pith is in the centre.
DICOT STEM: 1) Open collateralvascular bundle; 2) Under epidermis is collenchyma, not sclerencyma
WOODY STEM: 1) The "bark" of the tree consists of the periderm + the phloem ; 2) The vascular cambium cells divide to produce secondary xylem to the inside and secondary phloem to the outside
Gymnosperm stems 1)Has tracheids in their xylem2)Gymnosperm wood also often contains resin ducts
Leaf–lateral vegetative organ of plants, the general function its arephotosynthesis, transpiration. There are several types of leaves: 1) Bifacial) 2) Izolateral ; 3) Radial )
LEAF CROSS SECTIONDermal Tissue: outer single cell layer protective tissue. Cuticle: layer of waterproof wax on the outer surface of the dermal tissue. Ground Tissue: usually two layers, closely packed upper layer and loose lower layer – photosynthetic tissue. Air Spaces: rapid diffusion of carbon dioxide to the cells for photosynthesis. Guard Cells: control the closing and opening of the stomatal pore. Stomata: rapid entry of carbon dioxide into the leaf from the air.
