I selected links with images and information related closely to the observations described in lab Exercise 3 (Plant Roots) of your botany lab manual. Preview these resources as you prepare for the laboratory exercise and review these resources as you write your lab reports and study for tests.
 
 

Bring the radish seedlings that you germinated to this lab!

One section in the beginning of lab samples the diversity of plant root systems and a second section illustrates some roots of economic importance. However, emphasis of today's laboratory is external root structure and internal root anatomy (tissues and cell types).

Focus your attention on identifying tissues by their location, cell types and characteristic appearance. Visualize how sections of roots would be positioned in the intact root, and try to relate transverse (c.s.) with longitidinal sections. Learn to distinguish between (1) monocot and dicot roots, (2) young, mature, and woody roots and (3) prepare to contrast roots with stems which you will study next week.

 I will allow you to work mostly on your own in this lab period, but I will be available to help you locate or interpret any of the structures mentioned in the laboratory exercise. I will have numerous illustrations from reference books available to assist you in your study of roots. As you make your observations you might quiz yourself by seeing if you would be able to locate the following items and show them to me.

1. Adventitious root
2. Branch (lateral) root
3. Casparian strip
4. Cell plate (in telophase stage of mitotic cell)
5. Nucleus of a root hair
6. Pericycle
7. Phloem in Smilax root
8. Prophase nucleus of mitosis
9. Vessel element

I. DIVERSITY AND ADAPTATIONS OF ROOTS

- links to root types illustrate much of the diversity and adaptations mentioned in the lab manual

II. ROOTS OF ECONOMIC PLANTS - ROOT CROPS

- links illustrate most of the root crops mentioned in the lab manual 

III. ROOT GROWTH

Bring the radish seedlings that you germinated to this lab!

Work with the radish seedlings that you started at home and brought with you to this lab. Keep the Petri dishes containing the seedlings covered whenever possible. Don't leave the roots of a seedling exposed for more than the few seconds needed to mark them or measure them.

Select seedlings with roots that are straight and approximately 1 to 3 cm in length. Using a marker with silk threads spaced uniformly 1 mm apart, apply ink marks to the tip of the root of several radish seedlings. Try to get one ink mark as near the tip of the root as possible, with four or more additional ink marks spaced uniformly beyond.

Return the marked roots to the Petri dish as soon as possible. Take care that the ink does not blur.

IV. ROOT TIP

- a number of links illustrate root caps, root hair, and root tips in living roots mostly of grasses; others links illustrate regions, cell types, and mitotic figures in stained and sectioned roots.

V. SEEDS AND SEEDLINGS OF BEAN AND CORN

- As today's observations of roots of bean and corn review and extend the study started in lab exercise 1, you may wish to revisit some of those links, especially those of the bean and corn seeds and young seedlings.

VI. INTERNAL ROOT STRUCTURE

--I separated the links of internal structure as follows:

• Monocot roots (Smilax and Corn)
• Dicot roots (sunflower and Ranunculus =buttercup)
• Branch (or lateral) roots
• Woody roots

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