1. Chapter 22 Plant Structure

3. Leaf Structure  A leaf is a plant's principal organ of photosynthesis, the process by which sunlight is used to form foods from carbon dioxide and water.  Leaves also help in the process of transpiration, or the loss of water vapor from a plant.

4.  Stomata are breathing pores scattered over the leaf surface that regulate the exchange of gases between the leaf's interior and the atmosphere.

6. Cell Types in Plants

7. Primary Wall  Made of only 25% cellulose; forms a gluey matrix with the protein pectin that helps to stick cells together.  This gluey matrix is known as the middle lamella.  Areas exposed to air form the waxy cuticle.

8. Secondary Wall  Made of a greater amount of cellulose as well as lignin, which adds strength and support.  Adds to waterproof the cell.

9.  Plasmodesmata – areas for cell to cell communication.  Travel from plasma membrane to plasma membrane in adjacent cells

10. 3 Classes of Plant Cells  Parenchyma – makes up most of the herbaceous (soft, moist, green) part of the plant. They have pliable, thin primary cell walls.  Collenchyma – provides support for herbaceous tissue. For example, it makes up the thin outer layer that protects soft tissue in stems, like the long stringy fibers in celery.

11.  Sclerenchyma – these cells have very thick lignified cell walls. They are dead at maturity. They are used as support tissue and water conducting tissue.

13. Tissue Classes  Vascular Tissue – distributes substance through plants  Xylem – made of sclerenchyma cells. This tissue conducts water and minerals unidirectionally (up only) from the roots to the photosynthetic tissue.  Phloem – conducts sugar and other solutes. This movement is bidirectional and requires energy. A combination of all three cells types - predominantly parenchyma and collenchyma.

14. Dermal Tissue  Covers and protects photosynthetic plant parts.  An important product of these cells is cutin, a waxy substance that prevents water loss and fungal attack.

15. Ground Tissue  Where the basic functions of the plant take place, like photosynthesis and storage of food and water.  This tissue is primarily parenchyma but it can have any of the 3 cell types.

16. Meristematic Tissue  Meristem is actively growing tissue. It has not differentiated into a specific tissue yet, but its fate is determined by where in the plant it is found :

17. Apical meristem  Found in the tips of shoots and roots and is where the plant lengthens.  A bud is an undeveloped shoot that can be found on the ends or at nodes, where a plant branches.  A bud can develop into a stem, a leaf, or a flower depending on the hormone that signals its growth.

18. Lateral meristem  Found in the stem and roots and it is where the plant adds thickness.

19. Plant Growth and Regulation  Hormones are chemical signals produced in a source tissue and cause a response in a target tissue.  A small amount of hormone has a large affect.

20. Specific Hormonal Actions  Germination – from embryo to adult  Growth – increase in number, size or volume of cells.  Tropisms – growth responses to various stimuli.  Flowering Response

21.  http://www.gvsd.org/index.pl?id=12582&i sa=Category&op=show http://www.gvsd.org/index.pl?id=12582&i sa=Category&op=show  www.progressivegardens.com/.../plantove rall.jpg www.progressivegardens.com/.../plantove rall.jpg  www.scienceclarified.com/.../uesc_06_img 0338.jpg www.scienceclarified.com/.../uesc_06_img 0338.jpg  http://www.scienceclarified.com/Io- Ma/Leaf.html http://www.scienceclarified.com/Io- Ma/Leaf.html