WHAT PART OF PLANTS DO WE EAT? Onion STEM Do we eat the Potato STEM Flower Artichoke LEAVES Ovary Tomato OVARY Pollen Broccoli FLOWER Seeds Green Bean Leaves SEEDS Stem Carrot ROOTS Roots Which of these are fruits?
DID YOU KNOW? Plants out number animals. Most plants are flowers. Plants have special tissue just like us.
SPECIALIZED TISSUES IN PLANTS Seed plants have 3 principal organs:1. Roots2. Stems3. Leaves RecallCells make Tissues, Tissues make Organs, Organs make Organ systems, and Organ systems make Organisms.
DIRECTIONS – PARTICIPATION GRADE Fill in the blanks on your notes as we go along. If you see a someone will be called on for the answer. If you see a raise your hand if you know the answer. When we are done with notes you can work with a partner to complete the review on the back.
ROOTS Roots absorb water and nutrients for the plant. Roots anchor plants in the ground, holding the soil in place-preventing erosion. Roots protect plant from harmful bacteria and fungi.
ROOTS There are 2 main types of roots: Taproot – central, primary and deep to reach water below Earth’s surface. Fibrous – many branched thin roots. Helps prevent topsoil from being washed away.
ROOTS Roots have tiny hair-like projects called root hairs. Root hairs penetrate the spaces between soil particles and produce a large surface area. More surface area = more water and nutrient absorption.
ROOTS A root cap is at the end of a root. A root cap protects the root as it forces its way through the soil. As the root grows it secretes a slippery substance to lubricate the soil.
CHECKPOINT – RANDOM CALL Fibrous roots help prevent soil erosion by? A. – not branching B. – growing deep within the soil C. – extensive branching to which soil particles can cling
STEMS Stems are a transport system that carries nutrients from roots to leaves. Stems are a defense system to protect from predators and disease. Stems can be millimeters or as tall as 100 meters.
TRANSPORT IN PLANTS These 3 process help water move through a plant:1. Root pressure – roots actively transport molecules2. Capillary action – water sticks to the sides of the plant and helps it move from bottom to top3. Transpiration – evaporation of water from leaves pulls the water through the plant
CHECKPOINT What do a barrel cactus, a tree trunk, a dandelion stem, and a potato have in common? They are all stems!
STEMS Nodes are where leaves are attached to stems. Internodes are the spaces between the nodes. Buds can become new stems or leaves.
STEMS Primary growth in stems is when the plant grows up. Secondary growth in stems is when the plant grows out. Secondary growth results in wood.
STEMS PRIMARY GROWTH SECONDARY GROWTH You can count leaf You can determine scars to determine the age of a tree by years of primary counting its growth growth. rings.
MODIFIED STEMSWhat are these stems used for? FOOD!
LEAVES Leaves are photosynthetic systems. Broad, flat surfaces increase the amount of sunlight absorbed. Adjustable pores called stomata in the leaves help conserve water while letting oxygen and carbon dioxide enter and exit the leaf.
LEAVES To collect sunlight, most leaves have thin, flattened sections called blades. The blade is attached to the stem by a thin stalk called a petiole. The blade of a simple leaf (left) can be different shapes. In a compound leaf (right), the blade is divided into many separate leaflets.
LEAVES Recall these leaf parts: Cuticle – waxy coating Guard cell – gas exchange regulated with water pressure Stoma – pores on bottom of leaf Mesophyll – photosynthesis
CHECKPOINT – RANDOM CALL The opening and closing of stomata is regulated by changes in A. – water pressure in guard cells B. – air temperature C. – the sun’s brightness
PLANT TISSUE SYSTEMS Plants have 3 main tissue systems1. Dermal tissue – “skin” of the plant outmost layer of cells2. Vascular tissue – “bloodstream” transports water and nutrients in the plant3. Ground tissue – every other tissue besides dermal and vascular.
CHECKPOINT – RANDOM CALL Which tissue is found in the center of a plant stem? A. – Dermal B. – Vascular C. - Ground
1. DERMAL TISSUE Outer covering of plant is dermal tissue One layer of epidermal cells. Thick and waxy layer to protect from water loss known as the cuticle.
1. DERMAL TISSUE Trichomes are tiny hair-like projections that give the plant a fuzzy appearance. In roots, root hairs, a type of dermal tissue increases surface area to increase absorption. On the underside of leaves, the dermal tissue contains guard cells, which regulate water loss and gas exchange.
2. VASCULAR TISSUE Vascular tissue moves water and nutrients throughout the plant. Xylem – water conducting tissue Phloem – food conduction tissue
2. VASCULAR TISSUE - XYLEM Xylem zips up water Xylem moves water up through specialized cells called:1. Tracheids – long narrow tube-like cells2. Vessel elements – larger than tracheids and long like tubes.
2. VASCULAR TISSUE - PHLOEM Phloem – flows down food Phloem – cells that move the products of Phloem flows food photosynthesis down. 2 types of cells: down….what does1. Sieve tube elements – pipe to transport food xylem do?2. Companion cells – surround sieve tubes to help in transport
CHECKPOINT Which of the following is NOT one of the main tissues systems? A. – Ground B. – Epidermal C. - Vascular
3. GROUND TISSUE Cells between dermal and vascular tissue are called ground tissue. There are 3 types pictured below.
3. GROUND TISSUE - PARENCHYMA Parenchyma (puh-RENG-kih-muh) have thin cell walls and large central vacuoles. Leaves have parenchyma cells packed with chloroplasts for photosynthesis. Parenchymas have large central vacuoles meaning they are good for storage.
3. GROUND TISSUE - COLLENCHYMA Collenchyma (kuh-LENG-kih-muh) cell walls are thick. Collenchyma cells help support larger plants. Collenchyma cells make up the familiar “strings” of a stalk of celery.
3. GROUND TISSUE - SCLERENCHYMA Sclerenchyma (sklih-RENG-kih-muh) cell walls are extremely thick. Sclerenchyma cells make ground tissue strong and tough. Sclerenchyma cells are best for supporting the plant.
CHECKPOINT Which of the 3 kinds of ground tissue serve mainly for storage? A. – Parenchyma B. – Collenchyma C. - Sclerenchyma
PLANT GROWTH How do plants grow? Plants grow because cells at the tips of their roots and stems divide through the process of mitosis. Clusters of tissue where cells that divide are produced in meristems. Meristematic tissue is undifferentiated – meaning cells do not yet have a specific function.
PLANT GROWTH - MERISTEMS At the end of a stem or root there is an apical meristem. Apical meristems divide cells to increase stem and root length. Meristematic tissue is the only plant tissue that produces new cells by mitosis.
PLANT GROWTH How do plants grow? A. They eat and then their cells get bigger. B. The cells divide into new cells by mitosis. More cells = bigger plants. C. Plants add chemicals to make them biggerBONUS: Where does the plantget most of its atoms to makenew cells? SOIL AIRWATER LIGHT
PLANT GROWTH - MERISTEMS New cells have thin cell walls over time they develop and mature When a cell is matured it has specific cell parts (organelles) that do specific cell jobs The process of developing into a cell with a specific function is called differentiation. Example: leaf cells have many chloroplasts for photosynthesis.
PLANT GROWTH - MERISTEMS How differentiation works: A new cell is made in the stem apical meristem. Certain genes in the DNA are turned on. The genes code for the cell to have a bright pink color. FLOWER The example cell has differentiated into a ___________ cell.
REVIEW Take3 minutes and answer these questions at the end of your notes:22. What are roots adapted for?23. What are stems adapted for?24. What are leaves adapted for? http://www.quia.com/cb/22926.html Plant Part Game!