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Test 3- Outline+3a

Test 3- Outline+3a - NOTES FOR BIOLOGY 1002 Outline 3A...

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NOTES FOR BIOLOGY 1002 Outline 3A CHAPTER 24 Plant Anatomy and Nutrient Transport The basic design of land plants has two parts (see 24-1): - Root System - Shoot System For the Angiosperms the two variation of this basic design are seen in the two Classes (Monocots versus Dicots) (see fig. 24-2). MONOCOTS DICOTS Flower structure arranged in group of three arranged in groups of four or five Leaves narrow with parallel veins wider with branching netlike veins Vascular tissue scattered vascular bundles Ring of vascular bundles Roots Many smaller roots One main taproot Seed One cotyledon Two cotyledons >Plant growth and development Plants grow only in special regions. The cells in these regions are meristem cells . Meristem cells are undifferentiated ( totipotent ) embryonic cells. This means the cells have not become specialized (like radial/indeterminate cleavage in animals). Once plant cells mature they become differentiated cells and usually don’t divide again. Plant growth is mainly two-dimensional (up and down) and as a result plants grow longer not wider. This is the result of the location of the meristem cells. Meristem cells are found at both ends of the plant. These cells at the root and shoot tips are the apical meristems (see figs 24-9 and 24-15) The growth that occurs at the apical meristem is called primary growth . Primary growth continues throughout the life of a plant and is responsible for the increase in height of a plant. The other location of meristem cells is the lateral meristem . The lateral meristem is found in a ring like structure called the vascular cambium in dicots and conifers (see fig. 24-9). This ring of cells separates the xylem and phloem and is responsible for secondary growth .
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Secondary growth occurs later in the life of a plant and is responsible for the thickening of branches and trunks. Plants have three main tissue systems (see fig. 24-3) - Dermal Tissue System – from the protoderm - outside covering - Ground Tissue System – from the ground meristem - the in-between stuff - Vascular Tissue System – from the procambium - the pipes Two tissue types make up the dermal tissue system . - Epidermal tissue - Periderm The epidermal tissue forms the epidermis (skin) that covers the outside of the plant. Keeps the water locked into plant in the above ground portion -Made up of thin-walled cell with a waxy cuticle . Some epidermal cells produce fine hair-like structures called root hairs (see fig 24-17) or leaf hairs (see fig 24-4) below ground. Brings in nutrients from soil. The periderm tissue can replace the epidermis in older woody stems, branches and trunks. -Made up of thick-walled cork cells . These cork cells are waterproof and form the bark (see fig 24-13) The ground tissue system is composed of three tissue types (see fig 24-5): - Parenchyma tissue The parenchyma tissue has thin-walled living cells.
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