2Specialized Tissues In Plants A. Seed Plant Structure1. Roots2. Stems3. LeavesB. Plant Tissue SystemsC. Dermal TissueD. Vascular Tissue1. Xylem2. PhloemE. Ground TissueF. Plant Growth and Meristematic Tissue
3Seed Plant StructureThe cells of seed plants are organized into tissues and organs.The three main plant organs are roots, stems, and leaves.Roots absorb water and dissolve nutrients and anchor plants in the ground.Stems support the plant body and transport materials throughout the plant.Leaves are the main organs of photosynthesis. They also function in gas exchange.
4Root, Stem, and Leaf Tissues Dermal tissueVascular tissueGround tissue
5Plant Tissue SystemsWithin the roots, stems, and leaves are specialized tissue systems. The three main tissue systems:Dermal tissue is like the skin of a plant. It protects the plant and prevents water loss.Vascular tissue consists of xylem (move water throughout the plant) and phloem (moves sugars and other materials throughout the plant).Ground tissue is made up of all of the cells that lie between dermal and vascular tissues. (made up of 3 kinds of cells)Parenchyma cells: function in photosynthesis and storageCollenchyma cells: help support larger plantsSclerenchyma cells: make ground tissue tough and strong
6Plant Tissue Systems Cont. A fourth kind of tissue, meristematic tissue, is responsible for plant growth.Meristematic tissue is the only plant tissue that produces new cells by mitosis.The tips of stems and roots are made of meristematic tissue.
8Roots The two main types of roots are taproots and fibrous roots. Taproots: the primary root grows long and thick, while the secondary roots stay small.Fibrous roots: secondary roots that grow and branch outRoots have two main functionsTo anchor a plant in the groundTo absorb water and dissolved nutrients form the soil
9Taproots and Fibrous Roots Taproots (Carrots) Fibrous Roots (Grasses)
10Cross Section of Plant Root (magnification: 40x) The Structure of a RootEpidermisRoot hairsPhloemXylemApical meristemRoot capZone of maturationZone of elongationEndodermisGround tissue (cortex)Vascular CylinderGround tissue (cortex)EpidermisEndodermisVascular cylinderCross Section of Plant Root (magnification: 40x)
11Stems Stems have three important functions To produce leaves, branches, and flowersTo hold leaves up to the sunlightTo carry water and nutrients between the roots and leaves
12Plant stems grow in two ways Comparing Primary and Secondary Growth of StemsCharacteristicsWhere It OccursEffect on PlantHow It Is ProducedPrimary GrowthSecondary GrowthAt ends of plantsIncreases plant lengthBy cell division in the apical meristemIn stemIncreases stem widthBy cell division in meristems other than the apical meristem
13LeavesThe structure of a leaf is optimized for absorbing light and carrying out photosynthesis.To collect sunlight, most leaves have thin, flattened sections called blades.Plants can lose water out of their leaves as they exchange gases with the air (transpiration).To prevent major water loss plants allow air in and out of their waterproof covering only through small openings called stomata.Plants keep their stomata open just enough to allow photosynthesis to take place but not so much that they lose an excessive amount of water.
14Transpiration A B Evaporation of water molecules out of leaves. Pull of water molecules upward from the roots.
16The Internal Structure of a Leaf CuticleVeinsEpidermisPalisade mesophyllXylemVeinPhloemSpongy mesophyllEpidermisStomaGuard cells
17Transport in Plants Forces of Attraction Molecules of a similar substance are attracted to one another by a force called cohesion.Molecules of different substances are attracted to one another by a force called adhesion.
18Transport In Plants Phloem Xylem Sugar molecules Source cell Movement of waterMovement of sugarSink cell