Plant Science Chapter 6

Key Terms Stoma: opening within the epidermis that allows air into the leaf and water vapor and oxygen to move out of the leaf.

Chlorophyll: the green pigment of plant cells that capture light energy from the sun.

Photosynthesis: the food making process of plants turning light energy into sugar food source.

Vascular bundles: cells that create a vascular tube system that transports food in the phloem and water in the xylem bundles.

Xylem: vascular bundles that care water up the plant from the roots.

Phloem: vascular system that carries food created in the leaves through the plant.

Respiration: the function of the plant to release oxygen and take in carbon dioxide. The way a plant breaths.

Node: is the place of enlargement along the stem of a plant where you will find a bud.

Tap root: a plant that contains one strong central root. Example: carrot

Fibrous root: a root system with many fine roots that make up a matted root system. Example: grass

Leaves Plant leaves come in an almost endless variety of shapes and sizes. Leaves manufacture and store food for the plant. The energy from the sun is used to convert raw materials such as water, carbon dioxide, calcium, phosphorous, potassium, and nitrogen into food for the plant. Food created is in the form of sugars and carbohydrates as well as fats and proteins.

Structure of Leaves Leaves are made up of several different layers. Outermost layer consists of a coating of waxy material known as cuticle. –Helps the leaf retain water by slowing down the rate of evaporation inside the leaf. –Also helps prevent disease organisms from entering plant.

Second layer: under the cuticle is the epidermis. –Protects the leaf and covers the entire surface of the top and underside of the leaf. –Within the epidermis there are openings called stoma. –Stoma allows air into the leaf and water vapor and oxygen to move out. The opening is controlled by guard cells.

Between the epidermis layers is the mesophyll. Mesophyll is composed of two sub layers –Palisade: consists of elongated cells that contain chloroplasts containing chlorophyll, and are the sites of photosynthesis. –Spongy: contains air in contact with the atmosphere through the stoma. Within the spongy layer are vascular bundles. The vein like structures that contain the xylem and phloem.

Xylem: are tubes that bring the water from the roots to the leaves of the plant. Phloem are tubes that carry the products of photosynthesis to the other parts of the plant.

Photosynthesis The chemical reaction that takes carbon dioxide and water and converts these materials to sugar and oxygen. Only during daylight hours! 6CO2 + 6H2O C6H12O6 + 6O2

Respiration To maintain its systems and to grow, plants use some of the food stored. The braking down of food and utilization of the food is respiration. Reverse of photosynthesis C6H12o6 + 6O26CO2 + 6H2O + energy Takes place 24 hours a day.

Leaf Types Deciduous or Evergreen plants Why do plants deciduous drop their leaves? Page 128 Two basic parts –Leaf blade –Petiole

Identify plants Leaf type Leaf veins Leaf arrangement Leaf shape Leaf margin

Leaf Hunt Activity 1. Find a plant stem with 4 nodes 2. Find a tap root & a fibrous root 3. Find a simple and compound leaf. –Find two different leaves Compound & Simple Once all 3 items are collected students will take plant parts to a white sheet of paper and label the different parts of the leaf and stem, type of leaf or root system, and the purpose of the plant part. DUE at the end of the period Don’t forget to place your name on all your work!

Stems Purpose: –Support plant –Conduct water and nutrients from the roots to the branches and leaves. –Stores food for plant –Carries manufactured food by the leaves to the roots.

Two types of stems Herbaceous & Woody Green and relatively softhard Support comes from water pressure in stem. Composed of many layers that produces a strong structure Wilt easily without enough waterDo not wilt when water low Usually annual plants: live 1 year Ex: row crops, forages, veggies, house plants, etc. Ex: Trees and shrubs

Activity Draw a diagram of a woody stem. Page 136 figure 6-22 in the textbook. Label the parts and the function/purpose of each part.

Modified Stem Stem of a plant that grows horizontal to the ground and may be even under the ground. Also involved or purpose for plant is reproduction. Examples: stolons, runners, rhizomes, tubers, corms (bremuda grass, johnson grass, strawberries, potatoes, garlic, gladiolus, etc.)

Roots As much as half the weight of a plant may be in the root system. Purposes: –Take up water and nutrients –Store food –Anchor plant

2 Types of roots Tap & Fibrous Strong central root tapping deep into the soil. Primary root Many branches of fine roots Most dicots have tap rootsHelps hold soil in place to prevent erosion. Monocots: 1 cotyledon leaf when germinates Examples: carrot, trees, shrubsExamples; grass, corn, wheat

Specialized roots Adventitious roots: sprout from the stem like vines (grapes). Aerial roots: suspended in the air (orchids) Aquatic roots: suspended in the water (water lilies and seaweed).

Assessment and activites Complete self check packet Chapter 6 review questions page –Write-out questions and answers for true/false, fill-in blank, and discussion questions. –Plant nutrition video