Transcript Chapter One
Flowering Plants Structure and Organization Chapter 24 BIOL 1000 Dr. Mohamad H. Termos Non-vascular 2 Vascular 3 Organs of Flowering Plants Flowering plants share many common structural features. A typical plant features three vegetative organs roots, leaves stems, and Flowers, seeds, and fruits are structures involved in reproduction. 4 Organs of Flowering Plants Roots: Generally, the root system is at least equivalent in size and extent to the shoot system. Functions: Anchors, absorbs, produces hormones, stores minerals. Stems: Shoot system of a plant is composed of the stem, branches, and leaves. Main axis of a plant that elongates and produces leaves. Can be herbaceous or woody Leaves: major part of the plant that carries on photosynthesis 5 Plant cell review What things make plant cells unique? -cell wall -chloroplasts -large vacuoles 6 Tissues of Flowering Plants Meristematic tissue enables growth Apical meristems - at the tips of stems and roots Apical meristem produces: Epidermal tissue Ground tissue Vascular tissue 7 Tissues of Flowering Plants: Epidermal Tissue Forms the outer protective covering of a plant Epidermis contains closely packed epidermal cells Cuticle – waxy covering of epidermal cells 8 Epidermal Tissue Root Hairs Trichomes Stomata 9 Epidermal Tissue In older woody plants, the epidermis of the stem is replaced by periderm Major component is cork New cork is made by cork cambium 10 Tissues of Flowering Plants: Ground Tissue Ground tissue forms bulk of a flowering plant Photosynthesis Storage Support 11 Tissues of Flowering Plants: Vascular Tissue Xylem transports water and minerals from the roots to the leaves Phloem transports sucrose and other organic compounds from the leaves to the roots 12 Flowering Plants are Either Monocots or Eudicots Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Root Stem Leaf Flower Monocots Seed Root xylem and phloem in a ring Vascular bundles scattered in stem Leaf veins form a parallel pattern Flower parts in threes and multiples of three Eudicots One cotyledon in seed Two cotyledons in seed 13 Root phloem between arms of xylem Vascular bundles in a distinct ring Leaf veins form a net pattern Flower parts in fours or fives and their multiples Organization and Diversity of Roots Root cap contains root apical meristem Zone of cell division - contains primary meristems Zone of elongation - cells that are lengthening and becoming specialized Zone of maturation - fully differentiated cells 14 Organization and Diversity of Roots Primary root (taproot) Fleshy, long single root, that grows straight down. Stores food Fibrous root system Slender roots and lateral branches. Anchors plant to soil Adventitious roots - Roots develop from organs of the shoot system 15 Shoot tip and Primary Meristems 16 Organization and Diversity of Stems Herbaceous Stems: Mature non-woody stems exhibit only primary growth. Outermost tissue covered with waxy cuticle. Stems have distinctive vascular bundles (Herbaceous eudicots: Vascular bundles arranged in distinct ring, Monocots: Vascular bundles scattered throughout stem) Woody Stems: Primary tissues formed each year from primary meristems; increase length. Secondary tissues develop during first and subsequent years from lateral meristems; increase width. Bark: contains cork, cork cambium, and phloem 17 Wood: Secondary xylem that builds up year after year. Annual ring is made up of spring wood and summer wood. In older trees, inner annual rings, called heartwood, no longer function in water transport Tree Trunk Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. annual rings heart wood sap wood vascular cambium phloem cork a. Tree trunk, cross-sectional view b. Tree trunk, longitudinal view a: © Ardea London Limited 18 Organization and Diversity of Leaves Leaves contain: - Upper and lower epidermis: 1- Waxy cuticle, 2- Trichomes, 3- Stomata - Mesophyll: 1- Palisade mesophyll containing elongated cells, 2- Spongy mesophyll containing irregular cells with air spaces - Contains many chloroplasts 19 What do plants need to survive? sunlight water and minerals Carbon dioxide Leaves- Broad and thin to absorb more solar energy Stomata – open to allow gas exchange Roots: Water- enters through osmosis Minerals- absorbed and concentrated through active transport Stems/Leaves: Water transported from roots by: Root pressure Cohesion – water molecules “cling” together Roots stems leaves out of stomata Minerals – moved with the water and absorbed by cells that need them Photosynthesis: Produces organic nutrients for energy- sugars. Sugars need to be transported to plant parts that need the energy Sugar moves into phloem by active transport. Water follows due to osmosis Creates positive pressure of water that carries sugars to other plant parts then sugar removed actively Water leaves phloem due to osmosis xylem 20