01:119:116 Lecture Notes - Lecture 9: Cell Wall, Fibrous Root System, Axillary Bud
15 Mar 2016
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Document Summary
2 systems: root system, shoot system. 1st root to emerge: lateral roots. Branch from primary root: root hairs. Thin, finger-like extensions of root epidermal cells. Thick mat of slender roots spread out. Stem: bears leaves and buds, structure. Axillary bud - form lateral branches: main functions. Leaves: main photosynthetic organ, capture light, exchange gases, blade, petiole stalk. Grasses lack petiole: veins vascular tissue. Midrib major vein network: simple single, undivided blade, compound blade consists of multiple leaflets fig 35. 6, modified leaves. Bulbs underground stem with modified leaves. 1st line of defense: nonwoody plants. Epidermis single layer of tightly packed cells. Cuticle waxy covering prevents water loss: woody plants. Pariderm replaces epidermis in older regions: functions. Shoots guard cells specialized epidermal cells. Trichomes specialized epidermal cells in shoots. Xylem conducts water and minerals upward. Mostly from leaves to wherever needed: stele. All vascular tissue of a root or stem. Stem and leaf stele vascular bundles: separate strands xylem and phloem.
