2.  The cells of a seed plant are organized into different tissues and organs.  Three of the principal organs of a seed plants are ◦ Roots—absorb and transport water and dissolved nutrients, anchor plant to ground, protect from soil bacteria and fungi, hold plant upright ◦ Stems—support system for plant body, transport system for carrying nutrients, defense system for protection ◦ Leaves—photosynthetic system, protect against water loss, gas exchange

3.  Plants consist of three main tissue systems ◦ Dermal tissue: like the “skin” of a plant, outermost layer of cells. ◦ Vascular tissue: like the “bloodstream”, transporting water and nutrients throughout the plant ◦ Ground tissue—everything else

5.  The outer covering of a plant consists of epidermal cells.  Epidermal cells make up dermal tissue.  Cuticle thick waxy layer that protects the plant against water loss and injury.  Form root hairs in roots which increase surface area for absorption of water/nutrients.  underside of leaves, dermal tissue contains guard cells, which regulate water loss and gas exchange.

6.  Vascular tissue forms a transport system that moves water and nutrients throughout the plant.  xylem, (tracheids & vessel elements) a water-conducting tissue,  phloem, (sieve tubes) a food-conducting tissue.

8.  Cells that lie between dermal and vascular tissues make up the ground tissues.  Metabolic and structure functions!  In leaves – carry out photosynthesis (mesophyll) in stems – structural support in roots – storage and structural support

9.  In most plants, new cells are produced at the tips of the roots and stems.  A meristem is a cluster of undifferentiated tissue that is responsible for continuing growth throughout a plant's lifetime.  Near the tip of each growing stem and root is an apical meristem.  An apical meristem is a group of undifferentiated cells that divide to produce increased length of stems and roots. Lateral meristem = branch growth & Width growth in woody stems

11.  Two types of roots ◦ Taproots—primary root is long and thick while secondary roots are short.  Carrots, beets, radishes  Mainly in dicots ◦ Fibrous roots—many branches so that no single root grows larger than the rest.  Grasses  Mainly in monocots

12.  Anchor plant to ground  Protect plant from harmful soil bacteria and fungi  Transport water and nutrients to rest of plant  Hold plant upright against forces such as wind and rain.

13.  As minerals are pumped into the vascular cylinder, more and more water follows by osmosis.  This increases the pressure on the roots. This root pressure forces water through the vascular cylinder and into the xylem.  As more water moves in, the water in the xylem is forced upward through the root into the stem.  See Figure 23-10 on page 588.

14.  Stems have 3 important functions: ◦ Produce leaves, branches and flowers ◦ Hold the leaves up to sunlight ◦ Transport substances between roots and leaves.  Like the rest of the plant the stem is composed of three tissue systems—dermal, vascular and ground tissue.  Stems are surrounded by a layer of epidermal cells that have thick cell walls and a waxy protective coating.  Stems contain distinct nodes where leaves are attached and internodes between the nodes.  Buds contain undeveloped tissue that can produce new stems and leaves.

15.  Stems provide:  a support system for the plant body Lignin in woody stems.  a transport system that carries nutrients. Xylem Phloem  a defense system that protects the plant against predators and disease.

16.  In monocots, vascular bundles are scattered throughout the stem.  In dicots and most gymnosperms, vascular bundles are arranged in a cylinder

17.  Unlike many other organisms, plants grow throughout their live. New cells are continuously produced at the tips of roots and shoots.  This method of growth, occurring only at the ends of a plant is called primary growth.  Primary growth is produced by cell divisions in the apical meristem.

18.  To grow larger, the stems of plant must get thicker as well as taller.  The method of growth in which stems increase in width is called secondary growth.  This growth takes place in lateral meristematic tissues called vascular cambium and cork cambium ◦ Vascular cambium produces vascular tissues and increases thickness of stems over time. ◦ Cork cambium produces the outer covering of stems.

19.  Leaves:  are a plant’s main photosynthetic systems.  increase the amount of sunlight plants absorb.  Adjustable pores conserve water and let oxygen and carbon dioxide enter and exit the leaf.  More on leaves later. Copyright Pearson Prentice Hall