Plants

Plants and Photosynthesis An Overview of Plants A.Plant Cells 1.Unlike animal cells, plant cells have a cell wall, which provide structure and protection. 2. Most plant cells contain the green pigment chlorophyll. a.Photosynthesis – process where plants use chlorophyll to make food b.Chlorophyll is found in a cell structure called a chloroplast. 3. Many plant cells contain carotenoids- red, yellow, or orange pigments that are also used for photosynthesis. Picture of a plant cell Chlorophyll is contained in the chloroplast.

Plants and Photosynthesis C. When plants moved to land, they had to adapt to new conditions. 1.More sunlight and carbon dioxide were available. 2.To reduce water loss, plant developed cuticles- a waxy, protective layer, secreted onto the surface of the plant which holds water in. 3.To increase support, cell walls developed cellulose, a chemical compound that provides structure and support. 4.To reproduce, plant developed water –resistant spores and seeds From sea to land

ADAPTATIONS

Food Storage Plants store food in bulb structures in their roots below the ground or in their stems for the winter or times where light or nutrients are limited. Ex. Carrots, sweet potatoes, ginger, potatoes, onions, garlic, turnips, radishes. Why might some plants store extra food under ground instead of above ground?

Seed Dispersal Plants use different seed structures to insure dispersal (spreading) of their seeds. Ex. Dandelions, tree seeds (see Maple seed to left), nuts, fruit with seeds. How do you think each of the seed structures in the picture help the plant to disperse their seeds?

Pollination Flowering plants use different methods to attract pollinators to help fertilize eggs within their flowers. Ex. Flower color, flower shape, and nectar to attract various types of pollinators. What structures does the flower the left have that might help attract pollinators? Predict: What mouth shape would the pollinator need to access the nectar within this flower?

Leaf Shape/Structure Plants use different leaf shapes and structures to collect light to make food (photosynthesis) and to conserve water. Ex. Oval, lobed, rounded. In what ways might some of the leaf structures to the left be helpful to gather different amounts of available light?

Stomata : Microscope Lab

Stomata Under the Microscope Procedure: Obtain plant specimen. Paint a thick patch (at least one square centimeter) of clear nail polish on the underside of the leaf surface being studied. Allow the nail polish to dry completely. Tape a piece of clear cellophane tape to the dried nail polish patch. Gently peel the nail polish patch from the leaf by pulling on a corner of the tape and "peeling" the fingernail polish off the leaf. This is the leaf impression you will examine. Tape your peeled impression to a very clean microscope slide. Use scissors to trim away any excess tape. Label the slide with plant name. Examine the leaf impression under a light microscope at 400X. Search for areas where there are numerous stomata, and where there are no dirt, thumb prints, damaged areas, or large leaf veins. Draw the leaf surface with stomata. Count all the stomata in one microscopic field. Record the number on your data table.

Stomata Two stomata can be seen, one on either surface of this leaf section. Stomata are really plant pores which enable gas exchanges to take place, and water vapour to be lost. This has the benefit of moving water up the plant in a process called transpiration. The stoma (singular) can be seen in fine detail here surrounded by guard cells-{1}. The pore -{2} and the guard cells make up a single stoma. There may be as many as 6 million per typical leaf! The area just inside the internal structure of the leaf and below the stoma is the air space -{3} which brings carbon dioxide very close to the palisade parenchyma tissue; so diffusion gradients are maintained over the small distances between stomata and palisade parenchyma.

Stomata This is a much higher magnification of a stoma taken through an ordinary optical microscope. You can clearly see the open pore and the guard cells either side of the gap. Remember that you are looking at a section cut down through the leaf. Stomata should also be viewed by looking at a leaf surface under a microscope from above. This will help you understand the true shape and structure of stomata. Under Very High Powered Microscope