Structure and Function in Plants

1. Structure and Function in Plants An introduction to plant life

2. http://www.uic.edu/classes/bios/bios100/labs/plantanatomy.htmhttp://www.uic.edu/classes/bios/bios100/labs/plantanatomy.htm 1. A Macroscopic View Terminal bud • Leaves: • Site of photosynthesis Flower • Flower: • Reproductive structure • Produce fruit with seeds Leaf Internode Node • Stem: • Supports plant • Gives plant height • Contains vessels that transports materials from the roots to the leaves • Contains vessels that transports materials from the leaves to the rest of the plant Vascular Tissues Seeds Fruit Stem • Roots: • Secure plant to the ground • Take up mineral nutrients from the soil • Take up water from the soil Primary root Lateral root Root hairs Root tip Root cap

3. http://www.sirinet.net/~jgjohnso/plants.html The Roots - Macroscopic • Root Hairs: • Young roots grow very fine roots hairs to help the plant gain maximum amount of water when they are still very small and can’t reach so far into the surrounding soil • The root hairs increase the amount of surface area the root has and can therefore gather more water, this is more effective than growing large too quickly • Root hairs are made up of only one cell Root hairs

4. http://www2.mcdaniel.edu/Biology/botf99/rootuse/2roottypes.htmlhttp://www2.mcdaniel.edu/Biology/botf99/rootuse/2roottypes.html http://www.cspinet.org/cspi/images/ http://www.agry.purdue.edu/turf/weeds/violet/violet%20root.htm The Roots - Macroscopic Other plants have a fine network of fibrous roots as seen here in this violet plant. Roots than sit above the surface of the soil and help support the plant are known as adventitious roots. Plants can consist of one main root known as a tap root. The carrot is an example of this, can you give other examples?

5. http://www.sirinet.net/~jgjohnso/plants.html The Roots – Microscopic View What our eyes can’t see: The Roots Root Hairs Xylem – transports water from the roots to the leaves Phloem – transports water and sugars around the plant Xylem and phloem together are known as the vascular tissue or vascular bundle Endodermis - tissue that makes up the bulk of the root is the endodermis Apical meristem – where all new growth of the root occurs Root cap – protects the new cells (produced in the meristem) as the root pushes forward

6. http://csdl.tamu.edu/FLORA/fa02/fa02080.jpg http://aggie-horticulture.tamu.edu/syllabi/201h/ediblebotany/onionyellow.html The Stem - Macroscopic Modified stems include tubers such as potatoes and bulbs such a onions, garlic, and daffodils. The plant stores nutrients in these vegetables until it needs it later. You can see the roots on the underside of this onion. Tendrils are also modified stems. In this case they are not used as storage, but help support the plant by attaching to nearby structures.

7. http://faculty.uca.edu/~benw/biol1400/pictures/tilliastem.jpghttp://faculty.uca.edu/~benw/biol1400/pictures/tilliastem.jpg An Internal Microscopic View What our eyes can’t see: The Stem • Cross section of a stem: • The cambium marks the boundary between the xylem and phloem • The phloem is located in a circle around the outside of the cambium • The xylem is located in a circle on the inside of the cambium • Each year the xylem leaves behind a ring of growth – shown by the numbers 1, 2 and 3. Trees can be aged using this method

8. http://biology.ucok.edu/personalpages/bidlack/Botany/botanypics/default.htmhttp://biology.ucok.edu/personalpages/bidlack/Botany/botanypics/default.htm The Stem – Microscopic View What our eyes can’t see: The Stem • Xylem – longitudinal section: • Xylem vessels are long, thin, hollow and stacked end to end • They do not have a nucleus and are actually dead • They are lined by lignin that helps them keep their strength • Xylem cells transport dissolved mineral ions and water from the roots to the leaves • Transport is unidirectional, in an upwards direction only

9. http://biology.ucok.edu/personalpages/bidlack/Botany/botanypics/default.htmhttp://biology.ucok.edu/personalpages/bidlack/Botany/botanypics/default.htm The Stem – Microscopic View What our eyes can’t see: The Stem • Phloem – longitudinal section: • Cells are long and thin and stacked on top of each other • They contain a nucleus and are alive • Phloem cells transport water and sugars (sucrose) around the plant • Transport it is bi-directional, both up and down the plant • Movement of materials in the phloem is called translocation

10. The Leaf - Macroscopic These leaves have virtually no petiole and are arranged in a whirl around the stem. Leaves can sit opposite each other on the stem. Leaves are attached to the stem via the petiole This leaf is divided into many small sections. It is known as a pinnate leaf. Leaves can also alternate on the stem. http://csdl.tamu.edu/FLORA/fa02/fa02080.jpg

11. The Leaf - Macroscopic Cabbage, lettuce, spinach and bok choy are all leafy structures of plants. Celery is actually a modified petiole rather than a stem. Celery does not have a true stem. http://www.csdl.tamu.edu/FLORA/328Fall98/328VegLab/veglablist.htm

12. http://biology.ucok.edu/personalpages/bidlack/Botany/botanypics/default.htmhttp://biology.ucok.edu/personalpages/bidlack/Botany/botanypics/default.htm An Internal Microscopic View What our eyes can’t see: The Leaf • Leaf cross section: • If we cut across a leaf, turn it on its side and magnify it, we can see several distinct layers of cells Cuticle – protect upper leaf surface from moisture loss Upper epidermis Palisade cells (palisade means ‘a fence like structure’ in Latin). You can see their dark stained nucleus. These cells contain lots of chloroplasts for photosynthesis. Spongy mesophyll is given its name due to the air spaces between all the cells Stoma Lower epidermis

13. http://www.borg.com/~lubehawk/photosyn.htm#ans%20matching An Internal Microscopic View What our eyes can’t see: The Leaf Cuticle Upper epidermis Mesophyll – all the dark green dots represent chloroplasts Palisade cells Spongy mesophyll Lower epidermis Cell nucleus Vascular bundle Large central vacuole Phloem cells Xylem cells Guard cell Guard cell Stoma

14. H2O H2O H2O H2O H2O H2O H2O H2O http://www.sirinet.net/~jgjohnso/plants.html An Internal Microscopic View • Stomates: • Allow the gasses involved in photosynthesis in and out of the leaf. • They must also control the amount of water lost from the leaf. In a dry environment they need to stay closed most of the day. For the stoma to close the guard cells must remove water For the stoma to open the guard cells must fill with water Stoma Thick inner walls of guard cells Guard cells Guard cells

15. http://bee.airoot.com/beeculture/book/chap5/quince.html The Flower - Macroscopic Petal Anther - male Stigma - female Style - female Nectar site Filament - male Ovary - female Ovules Sepal – protects bud

16. References • Johnson, Jerry [no date] The World of Biology. Retrieved from the site http://www.sirinet.net/~jgjohnso/plants.html January 2004. • [No authour] [no date]. Retrieved from site http://www.cspinet.org/cspi/images/ January 2004. • [No author] [no date]. Retrieved from site http://www.agry.purdue.edu/turf/weeds/violet/violet%20root.htm January 2004. • [No author] [no date]. Retrieved from site http://www2.mcdaniel.edu/Biology/botf99/rootuse/2roottypes.html January 2004. • Waggoner, Ben [no date] Biology 1400. Retrieved from the site http://faculty.uca.edu/~benw/biol1400/pictures/tilliastem.jpg January 2004. • [No author] [no date]. Retrieved from site http://aggie-horticulture.tamu.edu/syllabi/201h/ediblebotany/onionyellow.html January 2004. • [No author] (2004) Botany 301. Retrieved fro the site http://www.csdl.tamu.edu/FLORA/tfplab/vegchar.htm January 2004. • [No author] (2003) Plants and People – Botany 328. Retrieved from site http://www.csdl.tamu.edu/FLORA/328Fall98/328VegLab/veglablist.htm January 2004. • [No author] [no date] Plant Structure and Function. Retrieved from the site http://www.uic.edu/classes/bios/bios100/labs/plantanatomy.htm January 2004. • Bidlack, Jim & Hinnger, Justin (2003) Plant Biology (Bio 1304) Lab Pictures. Retrieved from the site http://biology.ucok.edu/personalpages/bidlack/Botany/botanypics/default.htm January 2004. • Lubey, Steve (2002) Lubey’s Biohelp – Photosynthesis (the big picture). Retrieved from site http://www.borg.com/~lubehawk/photosyn.htm#ans%20matching January 2004. • [No author] [no date] Chapter 5: Tree Fruits and Nuts and Exotic Tree Fruits and Nuts. Retrieved from site http://bee.airoot.com/beeculture/book/chap5/quince.html January 2004.