Ch 36 Angiosperm Anatomy

1. Ch 36 Angiosperm Anatomy

2. Monocot Vs. Dicot Plants

3. Plant Organs: • A structure that contains different types of tissues and performs one or more specific functions. • Include the root, the stem, and the leaf. • Root system: part of plant underground. • Shoot system: part of plant above ground. - generally root system is at least equivalent in size and extent as shoot system.

5. Plant Tissues Three types of specialized tissues found in the roots, stems, and leaves of plants. 1)Epidermal tissue: Forms the outer protective covering of the plant. - cuticles, root hairs, stomata, cork 2)Ground tissue: fills the interior of the plant - the bulk of plant; contains paraenchyma, collenchyma, and sclerenchyma. 3)Vascular tissue: transports water and nutrients; also provides support. - Xylem & Phloem -Roots = vascular cylinder -Stems = vascular bundles -Leaves = leaf veins

6. Roots: Anchorage to soil, support, absorption, storage. Absorbs water and minerals from soil. Root hairs: - increase surface area to vol. ratio = inc. efficiency of absorption. - constantly replaced Produce hormones that stimulate growth of stems to coordinate w/ size of root. Perennials: plants that die and regrow the next season, store the products of photosynthesis in their roots.

7. Organization of Roots Zone of cell division: cells are continuously added to root cap. - have to be replaced b/c they are ground off as root pushed through soil Zone of elongation: cells become longer, and more specialized. Zone of maturation: Cells are fully differentiated - Root hairs

8. Root Diversity Taproot (d) Fibrous root system(m) Prop roots (m) Dodder Haustorium (parasitic)

9. Mutualism: endosymbiosis Mycorrhizae are fungus in roots. Fungi receives carb’s and amino acids from plant, which receives water and minerals via fungi. Root nodules: nitrogen fixing bacteria infiltrate root tissues. Plants cannot extract N2 from the air, these bacteria take it and convert to nitrates and ammonia for plant.

10. Plant Stems The main axis of a plant along with its lateral branches. Stems support leaves in such a way so that each leaf is exposed to as much sunlight as possible. Has non-living vascular tissue that transports water and minerals from roots and living vascular tissue for transport products of photosynthesis from leaves. Can expand in girth as stem gets longer for strength Some are used for storage; Cacti and tubers. Node = where leaves are attached Internode = region of stem between nodes.

11. Organization of Stems Just like roots, growth of stems happens at the shoot tips Shoot Apical Meristem = produces new cells that elongate and lengthens the stem.(primary growth) - Found w/in a leaf primordia that make up a terminal bud. produced at regular intervals called nodes. Axillary buds: usually dormant, can develop into branch shoots or flowers.

12. Removal of apical buds

13. Herbaceous Stems: mature non-woody stems. • Exhibit only primary growth (length). • Epidermis covered by waxy cuticle: prevent water loss. • Vascular bundles: where xylem and phloem are found. Xylem usually toward inside, phloem outside; separated by companion cells which make up the vascular cambium.

14. Herbaceous dicot stem Vascular bundles are arranged in a distinct ring around a central pith (store products of photosynthesis and H20)

15. Herbaceous monocot stem Vascular bundles are scattered throughout the stem w/ no well defined cortex or pith

17. Woody Stems: conifers and some dicots Has both primary (length) and secondary growth (girth) Secondary tissues develop: - Vascular cambium = produces secondary xylem and secondary phloem - Because of this continued 2o growth can’t make out individual vascular bundles. ID regions:Pith, Wood, and Bark

18. Annual Rings Vascular cambium is dormant in the winter and is extremely active making secondary xylem during the spring when there is a plentiful amount of moisture and leaves require much water for growth. As summer draws on into fall water becomes more limited and secondary xylem becomes more dense.

19. Annual rings as indirect evidence Older tree’s inner rings no longer function due to being plugged by deposits, resins, and gums. Substances like smog, smoke, and atmos. gasses can be trapped in these oily residues and can be measured. Tree rings can tell a very long, precise, and objective story about the earth’s molecular past.

20. Stem Diversity Stolons: above ground horizontal stems with nodes that act as roots; asexual reproduction. Rhizome: underground horizontal stems; tubers * Asexual reproduction *

21. Plant leaves: Photosynthetic organs. Consists of a flattened blade and a petiole which connects the leaf to the stem. Leaf veins: net pattern = dicots parallel pattern = monocots.

22. Organization of leaves • Epidermis: Often bears protective hairs and/or glands that produce substances that prevent herbivory. • Mesophyll: has two distinct regions, site of photosynthesis. Palisade mesophyll: elongated cells Spongy mesophyll: loosely spaced irregular cells; increase surface area for gas exchange. -what type of photosynthetic plant is shown in this diagram?

24. Shade plants have broad, wide leaves. Sun leaves are reduced in size and have sunken stomata. Herbivore defense.

25. Insectivorous Plants: Grow in nutrient poor soils, leaves adapted to get nutrients from prey. sundew Pitcher plant Venus flytrap

26. Plant Responses Adaptive for organisms to respond to environmental stimuli. - leads to longevity and survival of species Animals can alter their location or behavior in response to a stimulus, but plants cannot - change their growth pattern = tropisms

27. Phototropism Positive phototropism = growth towards the light (stems) Negative phototropism = growth away from light (roots) Cells on the side of the plant with stimuli (light) increase in size

28. Gravitropism Also has negative and positive. Root cap cells have sensors called statoliths which are a type of plastid that will settle to the lowest part of the cell.

29. Thigmotropism Unequal growth due to contact with solid objects Cells opposite of touch will elongate. Tendrils, vines, and other coiling plants.