STRUCTURE AND FUNCTION OF PLANTS CHAPTER 10

10A Plant Structure What is a plant? Kingdom Plantae Botany Producers Eukaryotic & multicellular Tissues Plastids Cell walls & cellulose Botany Anatomy Roots, stems, leaves Nodes

10A Plant Structure Roots Stems Leaves Root system Woody stems Taproot system Fibrous root system Stems Woody stems Herbaceous stems Turgor pressure Leaves Blade Smooth, toothed, deeply lobed Compound Leaf Leaflets Veins Parallel, Palmate, Pinnate Petiole Arrangement Alternate, Opposite, Whorled

10A Plant Structure Plant identification Internal Structure Shape and venation of a leaf, shape of its edge, and arrangement on the stem Internal Structure Two important characteristics to the survival of plants: cell walls & plastids Cell Walls Made of cellulose Support and bear weight of the entire plant Turgor pressure Plastids Chloroplasts Chlorophyll Other plastids (chromoplasts, gerontoplasts, leucoplasts, amyloplasts, proteinoplasts, elaioplasts) Chromoplasts are what the name describes, a place for the pigments to be stored and synthesized in the plant. These are found in flowering plants, fruits, and aging leaves. The chloroplasts actually convert over to chromoplasts. There are carotenoid pigments here that allow for the different colors you see in fruits and the fall leaves. One of the main reasons for these structures and the colors is to attract pollinators. Gerontoplasts are basically chloroplasts that are going through the aging process. These are chloroplasts of the leaves that are beginning to convert into different organelles or are being re-purposed, since the leaf is no longer utilizing photosynthesis (such as in the fall months). Leucoplasts are the non-pigmented organelles. Unlike the others we have talked about, leucoplasts have no color at all. They are found in the non-photosynthetic parts of the plant, such as the roots. Depending on what the plant needs, they may become essentially just storage sheds for starches, lipids, and proteins. They are more readily used for synthesizing amino acids and fatty acids. Leucoplasts are further subdivided into three different plastids: Amyloplasts are the largest of the three and are charged with storing starch. Then there are the proteinoplasts that help to store the proteins that a plant needs and are typically found in seeds. Finally, the elaioplasts are used to store fats and oils that are needed by the plant, specifically in seeds.

10A Plant Structure Plant Tissues Xylem Phloem Fibers Epidermis Bark Heartwood Sapwood Phloem Vascular bundles Fibers Epidermis Cuticle Bark Vascular Cambium Cork Cambium

10B Plant Functions Plants perform completely different that other organisms but they need they same things Water Movement Root epidermis Root hairs Xylem tissue Osmosis Transpiration Epidermis covers leaves for protection Stomata/Guard Cells release water vapor and gases Water lost during transpiration is replaced by water in the xylem Gas Exchange Aerobic cellular respiration Gas passes through the stomata in green parts of plants In woody parts oxygen passes through lenticels in the bark Underground, the thin root covering allows oxygen from the soil to pass Plants underwater have spaces to allow for gas exchange

Transpiration

10B Plant Functions Photosynthesis Sugar Occurs mostly in leaves Palisade layer – lots of chloroplasts Spongy layer – more air spaces, less chloroplasts Sugar Stored form of energy from sunlight Pass sugar to other plant parts through the phloem Some sugar molecules bond together to form cellulose Stored as starch stored by converting sugar to lipids

10B Plant Functions Growth Results in increased length and/or thickness Growth areas? What does a plant need for proper growth? What also affects growth? Environment Hormones Auxin Can you name specific plants that use hormones for production?

10C Plant Responses Tropisms Nastic Movements Photoperiodism Positive tropism Negative tropism Phototropism Thigmotropism Gravitropism Nastic Movements changes in turgor pressure Triggered by touch or light Photoperiodism Phytochromes Short day plants Long day plants Day neutral plants