4Plant OrgansPlant organs include their roots, stems, leaves, and reproductive structures. Each plant organ performs a specialized task in the life of a plant.Roots, stems, and leaves are all vegetative structures.Flowers, seeds, and fruits make up reproductive structures.
5Plant Organ FunctionsRoots support the plant and supply it with water and nutrients.Stems connect the root and leaves.Leaves capture energy from the sunlight and use it to make food for the plant.Reproductive structures attract pollinators and produce seeds and fruits.
6Root Structure Epidermis Cortex Zone of Differentiation Root Hairs Phloem TubesXylem (water transport)Zone of ElongationRoot CapMeristem
7The EpidermisThe epidermis is the outermost layer of cells surrounding the root.The cells of the epidermis are responsible for absorbing water and minerals from the soilEpidermis
8The CortexThe cortex is a layer of tissue between the epidermis and the vascular tissue.Cortex cells function in the movement of water and in food storage.Cortex
9Root HairsRoot hairs are found along the main root and perform much of the actual work of water and nutrient absorption.Most plants produce root hairs that only live a few days or a few weeks.As a plant grows, new root hairs form.Root Hairs
10XylemXylem is the supporting and water conducting tissue of vascular plants.Xylem
11PhloemPhloem is the food conducting tissue of vascular plants, made up of sieve tubes and other cellular material.Phloem
12MeristemThe meristem is at the tip of the root and is responsible for manufacturing new cells.This is the area where cell division and growth occur.Meristem
13RootsThe root is the first plant structure to emerge from a seed during germination.Roots are mostly found below the soil surface and represent about 50% of a plant’s weight.The primary functions of roots are to absorb water and nutrients from the soil and to support the plant in an upright position.
14Root FunctionsRoots distribute the food energy produced in the leaves to the rapidly growing areas found at the root tips.Some plants use their roots as a specialized food storage reserve.The first root to emerge from a seed is the primary root, or radicle.
15Roots (taproot)Plant root systems are classified based on the relative sizes of their primary and secondary roots.Plants such as dandelions, carrots, turnips, and most trees have a taproot.In taproot systems, the primary root thickens and becomes the dominant root.
16Roots (fibrous)In fibrous root systems, the primary and secondary roots are of similar diameter.They remain fairly close to the soil surface.Fibrous root systems help to prevent the erosion of topsoil during heavy rains.Plants such as onions, grasses, and corn have fibrous root systems.
18Stem Structure (External) Growing Point Young LeafTerminal BudAxillary BudNodesPetioleInternodeAbscission Layer
19StemsStems function as supportive structures. They hold a plant’s leaves up toward the sun so the leaves can capture energy from sunlight.Stems transport water and nutrients from the roots to the leaves, and food energy from the leaves to the roots.
20Leaf Structure Vein Midrib Expanded Portion of Blade (Lamina) Axillary BudBladestalk (Petiole)NodeInternodeBase of Leaf
21Midrib & VeinsThe midrib is the most prominent, central vein in a leaf.Lateral veins are secondary veins that branch from the midrib.Both midribs and lateral veins contain vascular tissue.VeinMidrib
22Leaf Blade (Lamina)Leaf Blade (Lamina)The expanded flat portion of a leaf is the leaf blade, or lamina.
23Petiole (Bladestalk)The petiole attaches the lamina to the plant stem.Petiole
24Axillary BudAn axillary bud exists on the stem just above the point where the leaf petiole attaches to the stem.Axillary Bud
25Parts of a Flower Pollen Grains Stigma Filament Style Anther Petal Pollen TubeOvuleEmbryo SacSepalMicrophyleIntegumentsOvaryReceptacle
26Complete Flowers Compete flowers have four basic parts: Sepals Petals StamensPistil
27SepalsSepals are leaf-like structures that form an outer ring around the base of a flower.Sepals enclose and protect a flower bud before it opens.The complete ring of sepals is called the calyx.Sepals
28Petals Petals are often the bright and colored part of a flower. Petal colors and scents attract specific pollinators.Petals
29Stamens The stamen contains both the filament and the anther. The filament is a stalk-like structure that holds the anther.Stamens are the male reproductive parts of a flower.Filament
30Pistil The pistil includes three parts: 1. Stigma 2. Style 3. Ovary
31Pistil 1. StigmaThe stigma is a sticky, flattened surface that projects upwards towards the pollinator.Birds and insects collect nectar from previously visited plants and brush against the sticky surface of the stigma.Stigma
32Pistil 2. StyleThe style is a supportive structure that holds the stigma in a position to maximize the chances of pollination.Style
33Pistil 3. OvaryThe ovary is an enlarged structure that contains the female sex cells, or ovules.The pollen tube grows through the ovary and into an ovule.Pollen TubeOvaryOvule
34ReceptacleThe enlarged part of the pedicel where it joins the flower is the receptacle.Receptacle
35PedicelThe pedicel (flower stalk) supports the flower.Pedicel
36AcknowledgementsKristi Falco, Graduate Assistant, Instructional Materials Service, researched and developed the information used in this PowerPoint Presentation.Christine Stetter, Artist, Instructional Materials Service, developed and illustrated this PowerPoint Presentation..Keith Zamzow, Curriculum Specialist, Instructional Materials Service, edited and reviewed this PowerPoint Presentation.Vickie Marriott, Office Software Associate, Instructional Materials Service, edited this PowerPoint Presentation.
37ALL RIGHTS RESERVEDReproduction or redistribution of all, or part, of this presentation without written permission is prohibited.Instructional Materials ServiceTexas A&M University2588 TAMUSCollege Station, Texas 2006