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PLANT FORM AND FUNCTION BEGINS Hi there. I’m Yosemite Sam to present Plant form and function to you kids! You may not realize it, but I’m named after a very famous National Park in California. It’s a high altitude protected forest so all of us can experience nature. Now I know I have a lot to learn about plants, but I sure appreciate their beauty, so I think this section can be interesting if you have a positive approach. Wonderin’ why I’m shooting my guns. Well, Plants got ROOTS and SHOOTS, that’s why. SHOOTS = STEM + LEAVES PHOTOSYNTHESIS- make sugar. Support cell metabolism energy needs REQUIRE- water and mineral supply from roots SHOOT Sugars Roots absorb water at the ROOT HAIRS to provide all plant parts with water and minerals NO PHOTOSYNTHESIS Most Roots are under the earth with no light! ROOT ROOTS need the sucrose supplied by the shoots to provide energy for cell metabolism. Water and minerals Well ain’t that somethin’. The shoots need the water supplied by the roots. The roots need the sucrose energy supplied by the shoots. They are both dependent on each other. That’s right Sam and I’m here to talk about the roots. Look at this carrot I’m holding. It’s a tap root used to store sucrose reserves for the plant. That’s why they’re delicious! ANCHOR the plant ABSORB – minerals and water STORE- food There are different types of ROOTS. 1 – fibrous roots (1) You know, the tap roots do not actually absorb much water. It’s the root hairs that do it. That’s why it’s better to transplant with the dirt surrounding the soil. There are multitudes of root hairs in that dirt. • mat of thin roots that spread out-monocots • tap roots (2) • 1 large vertical root • also produces many small lateral, or branch roots • dicots – root hairs (3) • increase absorptive surface area 3 2 Some ROOTS are modified. PROP ROOTS Support tall top heavy plants ex corn STORAGE ROOTS AERIAL ROOTS (STRANGLING) BUTTRESS ROOTS Support shallow roots (often in the rainforest.) PNEUMATOPHORE (AIR ROOTS) Oxygen levels in water are much too low for plant cells(roots drown). Roots get the 21% oxygen supply by having part of the root at the surface that providing the rest of the root with oxygen by the aerenchyma cells. Would you believe that some of the plants even have parasitic roots. These are Haustoria and they penetrate into the xylem and phloem vascular tissue of a host plant allowing the parasite to grow without the investment in growth of the tree trunk to reach light or roots that have to reach the ground for water. Parasitic plant with HAUSTORIA Palm trees are monocots and their roots are fibrous, but sturdy rhizomes help to anchor them into the ground RHIZOME = horizontal underground stems That’s enough rabbit. It’s time to talk about shoots. STEM NODE-point of leaf attachment INTERNODE-space between attachment BUDS- Terminal bud TERMINAL(apical) BUD – growth at the top increasing plant height AXILLARY BUDS- forms branches at nodes and specific angles Trimming hedges cuts off the terminal buds and promotes axillary bud growth. It’s all controlled by plant hormones. Terminal buds exhibit apical dominance unless you remove them. Some of the stems are modified for special purposes. Examples are….. BULBS STOLONS TUBERS RHIZOMES Onions are bulbs Strawberry runners are stolons that allow the plant to spread. Potato tubers are stems that store food under the ground Rhizomes of ginger and palm trees. My leaves do not have petioles Leaves are parts of the shoot too. Roots and stems are indeterminate –they continue to grow. Leaves are determinate. Not all angiosperms have leaf petioles The Leaf petiole FUNCTION OF LEAVES blade Photosynthesis producing ENERGY and ORGANIC molecules for structure of plant ex cellulose Gas Exchange for photosynthesis Transpiration-water loss through guard cells The cuticle of the leaf repels water and prevents water loss from the leaf cells. Transpiration SIMPLE VERSUS COMPOUND LEAF DESIGN Guard cells open for carbon dioxide but close to conserve water when transpiration is high Some of the types of modified leaves are…. TENDRILS SPINES SUCCULENTS BRACTS REPRODUCTIVE LEAVES Tendrils are used to hold the plant such as those of pea plants Cactus spines are actually leaves Agave is a succulent modified for storage of water. Remember tequila fermentation The red coloured leaves are bracts that surround a group of yellow flowers. Some leaves release adventitous plantlets which drop off the plant and form roots in the soil. Here is the leaf anatomy. Upper cuticle Upper epidermis Palisade layer Spongy layer Lower epidermis stoma Lower cuticle Remember me? You know plants are like animals in the organizational heirarchy. Plants have ORGANS performing a specific function, and these are made of TISSUES, which in turn are made of CELLS. ORGANS ROOTS STEMS LEAVES FLOWERS TISSUES DERMAL GROUND VASCULAR CELLS Parenchyma Collenchyma Sclerenchyma There’s different types of plant tissues. Some are even a little bit like that vermin rabbit that keeps showing up. PLANT TISSUES DERMAL= Epidermis (skin of plant) Dermal is ya skin the rabbit Ground is the eatin’ part of the rabbit. Vascular is the little heart and blood vessels Epidermis is no chloroplast single layer of tightly packed cells protecting plant surface GROUND TISSUE=Bulk of plant Includes photosynthetic mesophyll, storage VASCULAR TISSUE=transport system Xylem moves water and minerals Phloem moves sucrose water I heard that Sam. Now there’s PLANT CELL types as well, they’re all called ______chyma… PARENCHYMA- main cell type Eatin’ a fruit, potato,(stem) or salad(leaf) means eatin’ mostly parenchyma Least specialized Photosynthetic cells, Storage cells Fruit, stem, leaf, roots, storage cells Form into all other plant cell types That celery stringy stuff that gets caught in “yer” teeth. That’s collenchyma COLLENCHYMA –think Celery A peach pit is like wood inside the fruit. It’s made of sclerenchyma and called a SCLEREID Can make rope out of these fibers Thickened primary walls Provide support + remain alive SCLERENCHYMA-think wood Thick woody secondary walls. LIGNINxylem support- turns to wood Cells don’t elongate Dead at maturity Sure is hot in this desert. I need water. Plants got a vascular system that transports water around. There are two main tissues that conduct fluids in the plant. XYLEM – transports water and minerals In Greek xylon mean wood. So xylem= wood Okay? Tracheids and vessel elements (members)mature cells are dead PHLOEM – transports food (sucrose) water Sieve plate Phloos mean bark. So phloem is in bark. Sieve tubes and companion cells mature cells remain alive Sounds like a xylemphloem to me Sieve tube cells lose the nucleus, ribosomes, vacuoles So let me get this straight. The phloem has sieve tubes and companion cells both which are alive a maturity. The xylem is made of tracheids and vessel elements, both which are dead cells at maturity. PHLOEM XYLEM I’m a lookin around at all these plants and noticin’ that some of them die after one year but the others just keep comin’ back year after year. I’m an Angiosperm too Geranium Perennial plants, that’s what I want. No more havin’ to plant seeds each year like you have to do with annuals. Just plant them once and they keep comin’ back year after year. Annual plants Die after one season These here are flowers. What’s this ANGIE –SPERM and how would you classify your carrot? I’m an Angiosperm Daffodil tulip Perennial plants Regenerate each year Both are flowering plants: Angiosperms Phylum Anthophyta My carrot is special . It’s a biennial and survives for two years. Plant Anatomy Part 1 Ends