Unit 5: Plant Science

Mr. Nagel Meade High School Warm Up

• What significant roles do plants perform on Earth? How do you know? • Name two modern issues that could be interrelated with plants. IB Syllabus Statements

• 9.1.1 – Draw and label plan diagrams to show the distribution of tissues in the stem and leaf of a dicotyledonous plant. • 9.1.2 – Outline three differences between the structures of dicotyledonous and monocotyledonous plants. • 9.1.3 – Explain the relationship between the distribution of tissues in the leaf and the functions of these tissues. • 9.1.4 – Identify modifications of roots, stems and leaves for different functions: bulbs, stem tubers, storage roots and tendrils.

• http://click4biology.info/c4b/9/plant9.htm • Damon, Alan, et al. Pearson Baccalaureate: HL Biology. Pearson, 2007. 238-246. Print. Hierarchy

• Organize and describe the following terms: – Level 1 • Non-vascular land plants • Seedless Vascular Plants • Seeded Vascular Plants – Level 2 • Gymnosperms • Angiosperms – Level 3 • Dermal Tissue • Ground Tissue • Vascular Tissue Hierarchy • Level 1 • Non-vascular land plants – No conducting tissue; small and grow close to the ground » Ex: Mosses, Liverworts, and Hornworts • Seedless Vascular Plants – Well-developed vascular tissue; no seed production » Ex: Horsetails, Ferns, Club Mosses, and Whisk Ferns • Seeded Vascular Plants – Most living plants are in this group; extensive vascular system • Level 2 • Gymnosperms – Have seeds that do not develop within an enclosed structure • Angiosperms – Have seeds that develop within a protective structure • Level 3 • Dermal Tissue – Outer protective covering protects against physical agents and pathogenic organisms; prevents water loss and may be specialized for various purposes • Ground Tissue – Thin-walled cells that function in storage, photosynthesis, support and secretion • Vascular Tissue – Xylem and Phloem carry out long-distance conduction of water, minerals, and nutrients within the plant, while providing support. Plan Diagrams

Root Tissue Stem Tissue Leaf Tissue Mono vs. Di Monocots Dicots Embryo One cotyledon Two cotyledons

Veins Parallel venation in Netlike venation in leaves leaves Flowers 3 flower parts or 4 or 5 flower parts or multiples multiples Vascular Vascular bundles Vascular bundles System arranged throughout arranged as a ring in the stem stem Root Mainly fibrous Taproot (main root) with System surrounding fibers Pollen One opening on pollen Three openings on pollen grain grain Cotyledon: Leaf that emerges from a seed. Homework

Consider the LEAVES, ROOTS, and STEMS of various plants. Consider the variation that exists in these structures as you go from plant to plant. • Identify FOUR observed differences in each ‘organ’, with examples to support your observations. – Produce a simple bubble map to organize your thoughts.

Warm Up

• Compare and contrast Monocots with Dicots on three characteristics. • Identify the three main groupings that all plants fall into. Provide an example of each. • What roles do the xylem and phloem play in the plant? IB Syllabus Statements

• 9.1.4 – Identify modifications of roots, stems and leaves for different functions: bulbs, stem tubers, storage roots and tendrils. • 9.1.5 – State that dicotyledonous plants have apical and lateral meristems. • 9.1.6 – Compare growth due to apical and lateral meristems in dicotyledonous plants. • 9.1.7 – Explain the role of auxin in phototropism as an example of the control of plant growth.

• http://click4biology.info/c4b/9/plant9.htm • Damon, Alan, et al. Pearson Baccalaureate: HL Biology. Pearson, 2007. 238-246. Print.

Plant Organ Mods - Roots

• Roots – Prop roots • Thick adventitious roots that grow from the lower part of the stem to brace the plant. • Ex: Corn – Storage roots • Specialized cells within the root store large quantities of carbohydrates and water. • Ex: Carrot, Beet – Air roots (pneumatophores) • Produced by plants that live in wet places, these roots extend above the soil or water surface and facilitate oxygen uptake. • Ex: Mangrove, Cyprus tree – Buttress roots • Large roots that develop near the bottom of trees to provide stability. • Ex: Fig tree

Plant Organ Mods - Stems

• Stems – Bulbs • Vertical, underground stems consisting of enlarged bases of leaves that store food. • Ex: Onion – Tubers • Horizontally growing stems below ground that are modified as carbohydrate-storage structures. • Ex: Potatoes – Rhizomes • Horizontal stems that grow just below the surface to allow plant spreading. • Ex: Ginger – Stolons • Horizontal stems growing above ground that allow plant to reproduce asexually. • Ex: Strawberry plants

Plant Organ Mods – Leaves

• Leaves – Tendrils • Structures that coil around objects to aid in support and climbing (sometimes modified stems). • Ex: Pea plants produce tendrils from leaves – Reproductive leaves • Produce tiny plants along the leaf margins that fall to the ground and take root in the soil. • Ex: Kalanchoe plants – Floral leaves / bracts • Colored modified leaves that surround flowers and attract insects for pollination. • Ex: Poinsettia – Spines • Reduce water loss, may be associated with modified stems that carry out photosynthesis. • Ex: Cacti Meristems

• What are they? • What type of cells are similar in animals? • What is different about a meristem as compared to these animal cells? Meristems

• Two types – Apical • Primary growth • Root tips and stems (length) • Herbaceous, non-woody stems and roots – Lateral • Secondary growth • Increased thickness of plants (width) • Woody plants (shrubs, trees) – Vascular cambium  secondary vascular tissue produces secondary xylem on the inside (wood component) and secondary phloem on the outside – Cork cambium  bark produces cork cells of outer bark Phototropism

• Define phototropism. • What hormone is responsible for this behavior? • What parts of the plant exhibit high levels of this hormone? • Is the hormone produced in greater quantities or redistributed within the plant? • How do high concentrations of this hormone facilitate growth TOWARD a light source? HW Questions

• Why would girdling (the removal of bark and vascular cambium in a narrow ring all the way around a tree) result in the death of the tree? • If you remove the apical meristem from a dicotyledonous plant, what would be the effect on further plant growth? • Of what value are tubers, a type of stem modification, to the survival of the plant species?

Transpiration

• http://www.sciencemag.org/site/feature/mi sc/webfeat/vis2005/show/transpiration.swf

http://alex.edfac.usyd.edu.au/Methods/HSIE/Ayca/untitled/xerophyt.htm

Warm Up

• Name three environmental factors that will increase the rate of transpiration. • What plant part/feature has the most direct influence on the rate of transpiration? • What is the purpose of root hairs? IB Syllabus Statements

• 9.3.1 – Draw and label a diagram showing the structure of a dicotyledonous animal- pollinated flower. • 9.3.2 – Distinguish between pollination, fertilization and seed dispersal. • 9.3.3 – Draw and label a diagram showing the external and internal structure of a named dicotyledonous seed. • 9.3.4 – Explain the conditions needed for the germination of a typical seed. • 9.3.5 – Outline the metabolic processes during germination of a starchy seed. • 9.3.6 – Explain how flowering is controlled in long-day and short-day plants, including the role of phytochrome.

• http://click4biology.info/c4b/9/plant9.htm • Damon, Alan, et al. Pearson Baccalaureate: HL Biology. Pearson, 2007. 256-261. Print.

Anatomy of a Flower

• Sepals • Petals • Anther • Filament • Stigma • Style • Ovary Anatomy of a Flower

• Sepals – Protect developing flower while in the bud • Petals – Colorful to attract pollinators • Anther – Part of stamen which produces ‘male’ pollen • Filament – Stalk of stamen that holds up anther • Stigma – Sticky top of carpel (pistil) where pollen lands • Style – Part of carpel that supports • Ovary – Base of carpel where ‘female’ sex cells develop Birds and the Bees…

• Pollination – Process of pollen being placed on the female stigma – Leads to… • Fertilization – Male and female sex cells unite to form a diploid zygote – Leads to… • Seeds! (inside juicy fruit)

Seeds

• Require oxygen, water, and appropriate temperature Light-sensitive Plants

Plant Type Flowering and light Examples Long-day Radishes, spinach, and lettuce

Short-day Poinsettias, chrysanthemums, and asters Day-neutral Roses, dandelions, and tomatoes