Mr. Bouyer

Day 1 | Day 2 - 3 | Day 4 | Lab 1 | Lab 2 | Vocabulary Test

This Week's

Ground tissue Parenchyma Colenchyma Sclerenchyma Dermal tissue Epidermis Stomata Guard cell Cork Vascular tissue Xylem Phloem Meristem Apical meristem Lateral meristem Vascular cambium	Cork cambium Taproot Fibrous root Primary root Adventitious root Root cap Root hairs Hervaceous stem Woody stem Tree ring Springwood Summerwood Heartwood Sapwood Petiole	Simple leaf Compound leaf Hormone Auxin Gibberellin Ethylene Cytokinin Abscisic acid Tropism Phototropism Thigmotropism Gravitropism Hydrotropism Photoperiodism Critical length

Plant Tissues:
groups of cells that perform a common function.

What are the tallest trees in the world?

• Ground tissue system: ground tissue provides storage, metabolism, and support.

  Parenchyma

  • Large, loosely packed, rectangular cells with thin cell walls.
  • Responsible for photosynthesis and food storage.
  • Over 80 % of the cells in non-woody plants.

  Collenchyma

  • Elongated cells with uneven, flexible cell walls.
  • This tissue supports the growth regions of a plant.

  Sclerenchyma

  • Cells are short-lived with thick cell walls.
  • Serves to support the plant.
  • The cells that give a plant its "woody" characteristics.

  Lab # 2
  

• Dermal tissue system: dermal tissue forms the outside covering of plants and provides protection.

  Epidermis The outer layer of cells. Protects the plant and reduces water loss. Stomata Regulate gases passing into and out of the plant Usually located on the under side of leaves. Guard cells regulate the opening by changing water pressure within the cell to swell or shrink. Cork: closely packed cells protecting a woody stem.

• Vascular tissue system: vascular tissue provides transport and support.

  Lab # 1

  Xylem: straw-like tubes conducting water and minerals upward in a plant.

  Water is moved to the tops of very tall trees by capillary action, the adhesion/cohesion of water, transpirational pull, and root pressure. The largest force (transpirational pull) results from the evaporation of water from the leaves at the top of the tree. A tree behaves like a big straw, as water moves out of the leaves at the top and water moves in at the roots to replace it. Capillary action (what holds the water together) is a consequence of the high surface tension of water due to hydrogen bonding. Theoretically this process could continue at a very great height, but in practical terms trees are restricted to a maximum of about 400 feet (California redwoods) because of the requirements of stability. Water has been measured traveling up the stems of some oak trees at a rate of 60 meters per hour.

  Phloem: straw-like tubes conducting food downward in a plant.

   

  End Of Instruction practice test question #50

   

• Meristems: growing regions where cells divide.

  Apical meristem - located at the tips of stems and roots.

  Apical meristems produce growth in length, primary growth.

  Lateral meristem - located around the outer edge of stems and roots.

  Lateral meristems produce growth in circumference, secondary growth.

  Two types of lateral meristems:
  1. Vascular cambium - located between the xylem and phloem, it produces additional vascular tissues.
  2. Cork cambium - located outside the phloem, it produces the cork.

Computer Assignment 131:
This assignment must be completed by the end of class today to receive credit.
Scoring criteria

1. Paste this picture onto a PowerPoint slide with this layout.
   • Title the slide "Ground Tissues".
   • On the text side of the slide, use three or four words to tell what each type of tissue does for the plant.
2. Paste this picture onto a new slide with the same layout.
   • Title the slide "Guard Cells".
   • Label the guard cells in the top half of the picture.
   • On the text side of the slide, briefly describe how the cells are able to change shape to open or close the stoma.
3. Paste this picture onto a new slide with the same layout.
   • Title the slide "Vascular Tissues".
   • On the text side of the slide, briefly describe the function of each tissue.
   Save this set of slides and show them to your science facilitator.
   Your next assignment will add to these slides.

Day 2 - 3

What causes tree rings to form?

The 3 major plant parts:

Roots anchor plant in ground, absorb water and minerals, and store food.

• Taproot system - the primary root grows much larger than the other roots of the plant.
• Fibrous root system - the primary root does not grow large so that many roots of the plant are similar in size.
• Primary root - the first root to grow out of a seed.
• Adventitious roots - specialized roots that grow from plant stems or leaves.
• Root cap - a shield of parenchyma cells covering the apical meristem at the root tip.
• Root hairs - small extensions of a root, these greatly increase the surface area of the root for absorption.

(15 min)

Stems support the plant, transport materials in the plant, and serve as a storage area.

• Herbaceous plants have stems with very little sclerenchyma tissue which makes their stems "soft". These "non-woody" plants have vascular tissues arranged in bundles. These vascular bundles are either scattered throughout the stem or found in a ring toward the edge of the stem.
• Woody plants are mostly sclerenchyma, with the phloem located in a ring near the outside of the stem while the xylem is located more to the inside.
• Tree rings:
  • Springwood - when water is plentiful, wide xylem cells with thin walls are produced.
  • Summerwood - during dry weather, new xylem cells are smaller with thicker walls.
  • This produces a visible difference in the appearence of the woody stem. Since one sequence of this occurs each year, the age of a tree can be closely estimated by counting the "rings".
• Heartwood - when the xylem becomes clogged, it can no longer transport water and will take on a dark color. This can be seen in the center of most trees.
• Sapwood - the lighter-colored wood in a tree. Even if the cells are no longer living, they can still function to transport water.

End Of Instruction practice test question #14

Leaves are specialized for capturing sunlight for photosynthesis.

• The blade of a leaf is attached to the stem by a stalklike petiole.
• A simple leaf has one blade and one petiole.
• In compound leaves, the blade is divided into leaflets on the same petiole.

End Of Instruction practice test question #2

Computer Assignment 133:
This assignment must be completed by the end of class today to receive credit.
Scoring criteria

1. Paste this picture onto a PowerPoint slide with this layout.
   • Resize the picture to fill the whole background of the slide.
   • Use this style of WordArt to title the slide "Roots".
   • Fill the WordArt with a color that is easily visible.
   • Use some type of "3-D" effect on the title.
   • Use a zoom entry effect for the title 8 seconds after the slide appears.
2. Paste this picture onto a new slide with this layout.
   • Title the slide "Root Tissues".
   • One the text side of the slide, briefly describe where water and minerals travel, where food travels, where extra food is stored.
3. Paste this picture onto a new slide with this layout.
   • Title the slide "Root Tip".
   • Drag the picture to one corner of the picture area. It should snap to fill the whole area.
   • Use text boxes and arrows to label the following areas.
     • Root cap
     • Apical meristem
     • Elongation region
     • Root hair region (just visible at the left of the picture)
4. Go to "slide sorter view" in PowerPoint and duplicate slide number one.
   • Move the new slide into the fourth position.
   • Delete the background picture and paste this picture in its place.
   • Change the WordArt text to "Stems".
5. Paste this picture onto a new slide with this layout.
   • Resize the picture to cover from top to bottom on the left side of the slide.
   • Title the slide "Age of Twigs".
   • Use text to explain how one knows this twig is two years old.
   Save this set of slides and show them to your science facilitator.

With your table, ask your facilitator for a tree cross-section and a woody branch. Determine the age of both.

Day 4

What environmental stimulus causes plants and tree leaves to begin to grow in the spring?

Read this standardized test practice passage and answer the questions. You have six minutes to complete the assignment.

  (bio lab 245)
Tropisms: plant movement toward or away from an environmental stimulus.

Phototropism - a growth response to light. Solar tracking is the phototropism of leaves or flowers as they follow the sun's movement across the sky. Thigmotropism - a growth response to contact with a solid object. Thigmotropism allows vines to climb. It is thought that an auxin or ethylene are involved in this response. Gravitropism - a growth response to gravity. Roots are positively gravitropic, usually growing downward and stems are negatively gravitropic, usually growing upward. Auxins are probably responsible for this growth. Chemotropism - a response to chemicals. The growth of a pollen tube is in response to chemicals produced produced by the plant ovary. Hydrotropism - a response to water. Most plants have a positive response to water.

Photoperiodism: plant response to changes in the length of days and nights.

Critical length is the length of daylight above or below which a species of plant will flower. Long-day plants flower only when exposed to day lengths longer than their critical length. These are usually late spring and early summer flowers. Short-day plants flower only when exposed to day lengths shorter than their critical length. These are usually early spring and fall flowers. Day-neutral plants are not affected by the length of days and nights.

End Of Instruction practice test question #6

Concept Understanding: Why don't all species of plants produce flowers at the same time? Why do tree leaves change color in the fall?

With your table: Place a thick fold of paper towel in the bottom of a plastic petri dish. Liberly wet the towel. Lay several seeds on top of the wet towel and close the dish. Keep the towel moist for the length of the activity. After the seeds begin to sprout, turn the dish on edge and observe how the roots and stems begin to grow.

Research Links:

• Plant and Animal Cells - HHS Biology Class
• Plant Taxonomy - HHS Botany Class
• Botany 201 - Texas A&M University
• Plant Tissues - Georgia Perimeter College
• The Families of Flowering Plants - Delta Database
• A Glossary of Terms for Vascular Plants - Australian National Botanic Gardens
• Grafting - Central Florida Heritage Rose Society
• Propagation Resources - Texas A&M Horticulture
• Selected Botanical WWW Sites - University of Florida

California redwoods are the tallest trees in the world, growing nearly 400 feet tall.

Xylem cells grow large in the spring when water is plentiful, but much smaller in the summer when there is less water. The visible difference in these spring and summer cells causes what we know as tree rings.

Plants and tree leaves begin to grow in the spring as a response to the increasing length of daylight hours.