Plant Science part 1

Non-vascular Seedless vascular Seeded vascular

No conducting (vascular) tissue Usually small, grows close to the ground Must be found in moist environments Bryophytes such as mosses and liverworts

Vascular tissue well-developed No seeds produced Ferns, club mosses, horsetails

Seeds contain an embryo with nutrients and protective outer coat

Vascular tissue is extensive Most plants we know are in this category 2 categories-▪ Gymnosperms▪ Angiosperms▪ Monocotyledons▪ Dicotyledons

Two types of systems: Root System Shoot System: stem, leaf, flower

Plant organs: root, stem, leaf, flower referred to as plant parts

Anchorage Keeps plant in the soil Prevents soil erosion Holds stem in place

Absorption water dissolved minerals

Storage Starch Other nutrients

http://www.bio.miami.edu/dana/pix/taproot_fibrousroot.jpg

http://tchefty.wikispaces.com/file/view/rootsystems1.jpg/260637884/rootsystems1.jpg

http://kentsimmons.uwinnipeg.ca/2153/rootsystems1.jpg

Large long primary root Penetrate deep into the ground Small thin roots grow laterally off main root Strong anchoring system Examples: evergreen trees

Specialized to store water, food, nutrients

Better chance at drought survival

Examples: carrot, beet, turnip, radish

http://www.ontarioweeds.com/media/jpg/tropr_root.jpg

Many small roots that branch Increases surface area Better absorption of water and

minerals Less structural support Examples: peas, beans, lettuce

Small fibrous objects that branch off roots

Absorbs water and minerals

Zone of maturation: cells differentiate into different types of cells

Zone of elongation: allows the root to get deeper within the soil

Meristematic region: rapid mitosis of undifferentiated meristematic cells

Root cap: protects the meristematic region

Cells in the root have no chloroplasts and are not exposed to sunlight so they can not undergo photosynthesis to make their own food

Root cells must perform cellular respiration to obtain cellular energy

Glucose + oxygen carbon dioxide + water + energy

Glucose comes from the starch stored in the root Oxygen is absorbed through the soil

Stem Leaf Flower

Raises and supports branches, leaves and flowers

Transport of water and nutrients

In trees the main stem is the tree trunk

http://www.pxleyes.com/images/contests/bw%20tree%20trunks/fullsize/bw%20tree%20trunks_4b6283790291c.jpg

Young green stems can perform photosynthesis because they have chloroplast in their epidermal cells

Some are specialized for food storage Examples: sugar cane, potatoes

http://upload.wikimedia.org/wikipedia/commons/9/96/Sugar_Cane.jpg

Main function: Photosynthesis Parts of the Leaf:

Cuticle Epidermis Guard Cells & Stoma Palisade cells Spongy Layer Vascular Tissue

Outer layer of cells

Leaf epidermis produces cuticle

http://www.goldiesroom.org/Multimedia/Bio_Images/05%20Nutrition/15a%20Cross%20Section%20of%20a%20Leaf.jpg

Waxy substance that coats the exterior

Water proofing Protect interior

tissues Blocks passage

of gases

http://www.goldiesroom.org/Multimedia/Bio_Images/05%20Nutrition/15a%20Cross%20Section%20of%20a%20Leaf.jpg

Stoma (Greek for “mouth”) Pore-like openings in the

plant’s epidermis Opening size controlled by

two guard cells permits gas exchange

between the leaf’s interior and external environment.

larger opening, faster gas exchange

Where water is stored

Where the vascular tissues reside

Contains many chloroplast for photosynthesis

Cells stand tall and upright Top end exposed

to light Bottom end

exposed to the gases in the spongy layer

Scanning electron microscope image of a leaf from a Black Walnut tree. (Dartmouth Electron Microscope Facility/Dartmouth College)

http://cache.boston.com/universal/site_graphics/blogs/bigpicture/micro_11_14/m04_walnut_leaf.jpg

Dermal Tissue Vascular Tissue Ground Tissue

Outermost layer of a plant Epidermis: thin layer of cells that covers the

surface of leaf, stem and root Periderm tissue: bark on stem and large roots

of woody plants (replaces the epidermis)

Some dermal tissues have unique functions Root cells: root hairs (long extensions) Leaf cells: produce cuticle

Plant circulatory system Vessels that connect roots to leaves Transports water, dissolved minerals, and

sugars throughout plant, providing cells with materials to carry out life functions

Two types: Xylem Phloem

made up of long hollow tubes formed by non-living cell walls (left over from plant cells that have died)

transports water and dissolved minerals upwards from roots

Made up of elongated cells that are living Transports:

solutions of sugars (food) Dissolved nutrients Hormones

Bi-directional movement of materials downward to roots upward to leaves