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Trichomes
Trichomes are filamentous or glandular extensions of the epidermis. These can be unicellular or multicellular structures that contribute to plant functions in various ways. For example, some trichomes are protective in being unpalatable or irritating to insects or other foraging animals. Stinging Nettles are plants that use trichomes in this manner! Other plants possess numerous trichomes that form dense coverings over leaves and stems. These coverings create dead air space to protect plants from convective water loss. More specialized trichomes, like those of the predaceous sundew plant (Drosera sp.) produce sticky secretions that trap and digest insects.
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Labels
If you see the word "labels" on an image or a red or green light on a microscope icon, you have options to see labels or a comparison image.
Read the text carefully for descriptions and attempt to locate all described features first, much like you would with a real microscopic slide. Then, use the labels feature to check your observations.
Try this now! Roll over the red microscope light first, then the "labels" box!
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Roll-overs
As you can see, there are sequences. Occasionally the text will ask you to roll your mouse over a word, image region, or a specific structure to move on in the modules. Use these opportunities to apply your knowledge a little bit at a time. Roll your mouse over requested areas and allow it to rest while you read new material. Do not move across images randomly as this can trigger roll-overs before you are ready to move on. If this happens, you can navigate with these icons:
Follow directions carefully!
Try this now! First, roll over the "labels" image feature to find the trichome. Then, roll the pointer over the basal cell of the trichome for additional information.
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Virtual Microscopy
A microscope allows you freedom to move around a specimen slide, to examine and make comparisons between tissues, or to enlarge them for a closer look. Although difficult to recreate this experience here, there are a number of pages in this module that employ a strategy of altering image magnification as you rest your mouse on an icon of the microscope. Try this now on the 200x and 400x icons to vary magnification of this image.
Back to the module outline.
