Plant Structure and Taxonomy Travis DeLozier

Major Parts of Plants

Plant Varieties

Function of Root System Intake of water and nutrients Support Often the largest part of the plant (Some roots go down 6,8, or even 10 feet deep)

Types of Root Systems Taproot- The main root of a plant, it is heavy and thick and doesn’t have many side or lateral branches (Ex. Carrots, Sugar Beets) Fibrous- Thin, hairlike, and numerous. Hold soil much better than taproots systems. (Ex. Grasses, Corn)

Types of Root Systems Adventitious Roots- Roots that are above ground functioning as support and stabilization for the plant

Root Structure

Root Tissues Root Cap- Protects the tender growing tip as the root penetrates the soil Area of Cell Division- Very thin region. New cells multiply in two directions. A. Frontwards- small and tougher cells that replace the cells of the root cap B. Backwards- Tender cells are produced and help the root tip grow longer

Root Tissues Apical Meristem- Responsible for the elongation of the root Area of Cell Elongation- Cells become longer and specialized. Xylem- Responsible for carrying water and nutrients from the soil to the upper portion of the plant Phloem- Carries manufactured food down form the leaves to other plant parts

Root Tissues Area of Cell Maturation- where cells mature and root hairs emerge Root Hairs- small microscopic roots that play a major role in water and nutrient absorbtion.

Stems- support the leaves, flower, and fruit

Types of Stems Woody- Tough and winter hardy. Often have bark around them. Herbaceous- Succulent, often green, and will not survive winter in colder climates

Modified Stems Bulbs- Shortened stems surrounded by scales ex. Onion Corms- Thickened, compact, fleshy stems ex. Gladiola Rhizomes- Thick stems that run below the ground ex. Johnson Grass Tubers- Thickened, underground stems that store carbs ex. Irish Potato

Parts of Stems Some of the same internal parts as roots Xylem and phloem continue to run the length of the stem and into all of the branches Dicots- occur together in tissues called vascular bundles Monocots- occur in separate areas

Parts of Stems Node- swollen portion of stem where buds and leaves originate Internode- area between the nodes Lenticles- Pores on the stem that allow passage of gases in and out Axillary Bud- buds along side the axis of the stem Terminal Bud- located at the tip responsible for terminal growth

Leaves Manufactures food for the plant by using light energy Phototropism- plant leaf is capable of adjusting its angle of exposure to the sun

Leaf Types Simple- A single leaf arising from a stem Compound- Two or more leaflets arising from a common point on the stem

Leaf Arrangement

Leaf Shapes

Leaf Margins

Leaf Parts tip- the terminal point of the leaf. blade-the flattened, green, expanded portion of a leaf. margin- edge of a leaf. midrib-the most prominent central vein in a leaf. lateral veins-secondary veins in a leaf. petiole-the leaf stalk (connects blade to stem). stipules-leaf-like appendages (at the base of petiole of some leaves).

Internal Structure of a Leaf

Internal Structure of a Leaf Cuticle-Topmost layer of leaf. Waxy and serves as a protective covering Epidermis- protects the inner leaf Palisade Mesophyll- a layer of elongated cells located under the upper epidermis. These cells contain most of the leaf's chlorophyll, converting sunlight into usable chemical energy for the plant.

Internal Structure of a Leaf Spongy mesophyll - the layer below the palisade mesophyll; it has irregularly-shaped cells with many air spaces between the cells. These cells contain some chlorophyll. Vein (vascular bundle) - Veins provide support for the leaf and transport both water and minerals (via xylem) and food energy (via phloem) through the leaf and on to the rest of the plant.

Internal Structure of a Leaf Stoma - (plural stomata) a pore (or opening) in a leaf where water vapor and other gases leave and enter the plant. Guard cell - one of a pair of sausage-shaped cells that surround a stoma causing it to open and close

Flower Parts

Flower Parts Male part is the stamen which consists of the anther and filament Female part is the pistil which consists of the stigma, style, ovary, and ovules

Male Flower Parts (Stamen) Filament- thin, stem-like stalk, supporting anther Anther- sac located at the tip of the filament that contains pollen.

Female Flower Parts (Pistil,Carpel) Stigma- upper part of pistil where pollen is deposited Style- stalk between stigma and ovary Ovary- base of pistil which holds the ovules Ovule- reproductive structure inside ovary

Flower Parts Petal - colorful and often scented part of the flower that attracts insects. Collectively called the corolla Sepal- part of which encloses the bud before it opens. Collectively called the caylx

Stamen Carpel Anther Filament Stigma Style Petal Ovary Ovule Sepal Receptacle Sepal all stamens = androecium all carpels = gynoecium all petals = corolla all sepals = calyx Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Flowers Perfect Flower- Contains the stamen, pistil, petals, and sepals Imperfect Flower- Missing any of the parts listed above

Fruits and Vegetables Pollination- Union of the pollen with the stigma Upon fertilization the seed ripens in the ovary. The pistil enlarges and becomes the fruit. The true fruit is actually the seed itself. The fruit is a ripened ovary, not a vegetable. Ex. Tomato is a fruit because it is a product of a ripened ovary Vegetables can be any part of the plant grown for edible parts. May be the root, stem, leaf, or ripened flower. Another type of fruit is the nut. Ex. walnut

Plant Taxonomy Taxonomy- the science, laws, and principles of classification. Plants are given Latin names Carl Linnaeus, a Swedish botanist, developed the present system in 1753 Brassica oleracea var. italica L. Broccoli Daucas carota L. Carrot Ipomea batatus L. Sweet Potato