PLANTS

1. PLANTS Plants play an important role in an ecosystem. They are autotrophic organisms that carryout photosynthesis 6H2O + 6CO2 + sunlightC6H12O6 + 6O2.

2. PLANT CHARACTERISTICS • Multicellular eukaryotes • Photosynthetic autotrophs containing chloroplasts. • Non-mobile (fixed to one spot) • Cell walls made of cellulose • Responds to environment and grows through the use of hormones

3. Plant Diversity The Evolution and Classification of Plants

4. Plant Overview Evolution of Kingdom Plantae Fossil and biochemical evidence indicates plants are descended from multicellular green algae. Between 500 and 400 million years ago, some algae made the transition to land, becoming plants by developing a series of adaptations to help them survive out of the water.

5. Plants Make the The Move to Land The ancestors of plants were multicellular green algae. They were completely immersed in water & dissolved minerals. To move onto land, plants had to solve these problems: How to get chemical resources (water, minerals, oxygen, and carbon dioxide) separated into air and soil How to transport resources within the plant. How to prevent from drying out How to reproduce without water

6. An Adaptation (solution)- Have body parts extending into both air and soil • Shoot – portion of a plant grows mostly upward and aboveground. • Root –portion of the plantthat grows mostly downward and belowground.

7. Some more Adaptations (solutions)- Develop a vascular system to transport resources in plant Have a protective layer – cuticle (waxy outer layer) to keep from drying out Specialized structures for reproduction including spores & seeds that do not dry out

8. Plants are classified based on whether or not they have • Vascular System (transport) • Seeds • Flowers (enclosed seeds)

9. Nonvascular Plant Vascular Plant Concept Map: Plants are divided 1st by whether or not they have a vascular system. Plants Bryophytes Has NO Vascular Tissue Has Vascular Tissue Tracheophytes

10. Bryophytes - NONVASCULAR Most primitive plants Found in moist, shady areas NO vascular (transport) system Small size due to no vascular tissue No true roots, stems, or leaves Needs water for reproduction. Reproduces using spores, -a water-proof single cell that can grow into a new organism. Most common example: Mosses

11. Typical Moss Plant (most common bryophyte) Spores form inside the capsule. Notice the problem of nutrient separation into air and soil is solved with underground and above ground parts. (Although NO TRUE roots, stems or leaves are present)

12. Tracheophytes -Vascular Plants- • Contains two types of specialized vascular tissues for transport water and other materials inwithin the plant. • Presence of a vascular system allowed plants to become tall. • Has specialized organs: roots, stems, and leaves.

13. Plant Overview • Xylem - type of vascular tissue in plants that contain hard walled conducting cells that transport water and dissolved minerals upwards from the roots to the leaves. • Phloem -type of vascular tissue in plants that contains soft-walled conducting cells through which organic compounds are transported throughout the body of a plant. http://www.pearsoned.ca/school/science11/biology11/sugartransport.html

14. Tracheophytes are divided into two groups by whether or not they reproduce with seeds. Tracheophytes Seeded Seedless Ferns use spores

15. The Fern - a seedless vascular plant There are 11,000 species of ferns. • Contain a vascular system. • They grow in moist, shady habitats. • Has underground stems, roots, & large leaves called fronds. • Reproduce using spores, Not seeds. Sori

16. SEEDLESS VASUCLAR PLANTS DO NOT MAKE SEEDS • Rhizomes – horizontal underground stem. • Cone – in plants, cluster of non-green spore-bearing leaves.

17. Seed-Bearing Tracheophytes ADVANTAGE: Developed reproductive strategies that do not need water: • Seed contains • A fully developed embryo • Food supply for embryo • A water-proof seed coat to keep from drying out • Sperm transferred in water-proof pollen through pollination by wind or by animals. • Developed seed-bearing structures: Cones and Flowers

18. VASUCLAR TISSUE, SEEDSMADE PLANTS SUCCESSFUL • Seed plants - vascular plant that produces seeds. • Seed –a structurethat consists of a plant embryo surrounded by a protective coat. • Embryo – early stage in development of plants and animals

19. The two Seeded Tracheophyte groups are divided by whether or not they have enclosed seeds - protected inside a fruit or if seeds are exposed to the environment. Tracheophytes Seeded Seedless Ferns use spores Gymnosperms Angiosperms “naked” or exposed seeds Flowers produce fruit w/ enclosed seeds

20. Gymnosperms - “naked seed” • Cycad (Sago palm), • Ginkgo, • Conifer (pine, spruce, firs, cedars, sequoias, redwoods, junipers, yews, & cypress trees) Sago Palm Ginkgo Ginkgo

21. Sequoia Gymnosperms-Conifers • Most common gymnosperms are Conifers • Conifers have leaves called needles or scales have a reduced surface area and thick waxy coat on the needle to reduce water loss and prevents freezing. Juniper Pine

22. Conifer Reproduction Pollen • Male cones produce pollen and the female cone produces eggsand seeds. • Pollen is inefficiently transferred by the wind. • Once mature, the scales on the female cone dry out and open scattering the seeds by the wind. Seed Cone Pollen Cone

23. Angiosperms- “enclosed seeds” • These are flowering plants the encourage direct and efficient pollen transfer (smell, color and offering nectar) • Pollinators are flying insects, birds, and bats that transfer pollen from flower to flower. • Flowers contain ovaries, which is where eggs/seeds are produced. • A fruit is the pollinated ovary containing mature seeds.

24. Fruit can aid in dispersal of seed to reduce competition with parent plant. • Winged fruit – glides to new location (maple fruit) • Floating fruit – can float to new locations (coconut) • Fleshy fruit - sweet bright colored fruit have seeds that survive the digestive system of animals that eat the fruit (apple) • Spiny fruit- Velcro like projections attach to the fur of animals (cockleburs) Maple seeds: Winged fruit Burdock: Spiny fruit

25. Angiosperms- “enclosed seeds” • Monocots and Dicots are types of angiosperms, or flowering plants. • Monocots produce seeds with one seed leaf. Most monocots produce flowers, which have parts that are generally in multiples of three. Monocots have long narrow leaves with parallel veins. • Dicots are flowering plants that produce seeds that have two leaves. Dicots produce flowers, which parts are in multiples of 2,4, or 5. The leaves have branched or netted veins.

26. Structure of Plants

27. A. Functions of Roots • Anchor & support plant in the ground • Absorb water & minerals • Hold soil in place Fibrous Roots Root Hairs

28. Root Types Tap Root 1. Fibrous Roots:branching roots hold soil in place to prevent soil erosion Ex. Grasses 2. Tap Roots – larger central root reaches deep water sources underground Ex. Trees, Carrots, & Dandelions

29. The Structure of a Root Root Hairs • Root Hairs: increase surface area for water & mineral absorption • Meristem: region where new cells are produced • Root Cap: protects tip of growing root Phloem Xylem Meristem Root Cap

30. Roots – function and structure • Hold plant in position • Absorb water and minerals from the soil • Specialized cells to increase surface area for water intake Cross Section Longitudinal Section

31. Wheat seed Root hairs • Fragile parts of cells that grow from the main root • They massively increase the surface area for absorption

32. Stele or Central Cylinder

33. Functions of Stems • Support system for plant body • Transport system carries water & nutrients • Holds leaves & branches upright Looking at the picture to the left: What years had the most rain? What years experienced the worst drought? Each light and dark tree ring equals one year of annual growth. Light rings for fast spring growth, dark for slow summer growth. Smaller rings tell of past droughts that have occurred.

34. Functions of Leaves • Main photosynthetic organ • Broad, flat surface increases surface area for light absorption • Have systems to prevent water loss • Stomata open in day but close at night or when hot to conserve water • waxy cuticle on surface • System of gas exchange • Allow CO2 in and O2 out of leaf Elephant Ear Plant

35. LEAVES CARRY OUT PHOTOSNYTHESIS Petiole - Slender stalk that attaches the blade of a leaf to a stem.

36. Leaf Structures Leaf Cross-Section Cuticle • Cuticle: waxy layer; covers upper surface • Protects leaf against water loss • Veins: transports water, nutrients and food • Made of xylem and phloem • Mesophyll: contains cells that perform photosynthesis b/c they contain Chloroplasts. Veins Mesophyll Stoma (Opening) 2GuardCells Surround each Stoma Stoma- singular Stomata-plural

37. Leaf Structures • The leaf is a mass of ground and vascular tissue surrounded by an epidermis. • The xylem and phloem make up the veins of a leaf. • Mesophyll in Greek means “in the middle of the leaf” • Most plants have two layers of mesophyll. • The palisade lies beneath the upper epidermis. • The spongy mesophyll lies above the underside of the leaf) • Lower Epidermis are where the stomata are located.

38. More Plant Parts… • Guard cells: • cells that open and close the stoma • Stomata: openings in leaf’s surface; when open: • GAS EXCHANGE: Allows CO2 in & O2 out of leaf • TRANSPIRATION: Allows excess H2O out of leaf Guard Cells Stoma

39. Function of Stomata What goes out? O2 H2O What goes in? CO2 • What process involves using CO2 andH2O releasing O2 as a waste product? • Photosynthesis • What is the plant using this process to make? • Carbohydrates-glucose • If the plant needs water for photosynthesis, why is water coming out of the stoma? Guard Cells Guard Cells Stoma Closed Stoma Open Stoma

40. Function of Guard Cells • These stomata (leaf openings) naturally allow water to evaporate out. • Why would the plant close stomata with guard cells? • Prevent excess water loss through transpiration. (conserve water) • So what is the point of having stomata? • Allow gas exchange for photosynthesis Guard Cells Guard Cells Stoma Closed Stoma Open http://www.tvdsb.on.ca/westmin/science/sbioac/plants/stoma.htm

41. Transport of Materials Capillary Action - the movement of water in upward direction in a small area. Limitations: Water can move only a few cm up Root Pressure – H2O moves up by osmosis Limitations: Only move water about 1 meter Properties of Water Cohesion - sticks to itself Adhesion – sticks to objects

42. Plants find a use for Transpiration • Transpiration: loss • of excess water from plant leaves • 2. Significance: • Transpiration causes enough pressure to help pull water (& required nutrients) up stem from roots. • As part of the water cycle, trees transpire water back into the atmosphere. • Transpiration provides much of the daily rain in rainforest. A average size maple tree can transpire 200 liters of water per hour during the summer. Transpiration is the #1 driving force for pulling water up stems from roots.

43. Plant Responses and Adaptations

44. Hormone Action on Plants Hormone-producing cells • A. Plant cells can produce hormones: which are chemical messengers that travel throughout the plant causing other cells called target cells to respond. • B. In plants, hormones control: • Plant growth & development • Plant responses to environment Movement of hormone Target cells Cells in one blooming flower signals other blooms using hormones to open.

45. Plant cells will send signals to one another to tell them: • When trees to drop their leaves. • When to start new growth. • When to cause fruit to ripen. • When to cause flowers to bloom. • When to cause seeds to sprout. Leaf Drop http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropisms.html Cactus Blooming Fruit Ripening Tree Budding Sprouting Corn Seeds

46. Plant Hormones • One way that cells can communicate is by hormones. • Membranes contain special cites for receiving the information. • It is the specific shapes of the hormones (shape is unique for each) that the receptors respond to.

47. Ethylene causes Fruit to Ripen • Fruit tissues release a small amount of ethlyene • Causes fruits to ripen. • As fruit become ripe, they produce more and more ethlyene, accelerating the ripening process. Ethylene released by apples and tomatoes causes fruit to age quickly.

48. Plant Tropisms • Tropism: the way a plant grows in response to stimuli in the environment. • Phototropism: growth response to light -Plants bend towards light • Geotrophism: growth response to gravity -plant roots grow down with gravity, shoots (stems) grow up against gravity and out of the soil. • Thigmotropism: growth response to touch -vines grow up around trees, venus flytrap closeswhen leaves are touched

49. What type of tropism is shown in these pictures? Phototropism Geotropism Thigmotrophism Thigmotrophism Geotropism Phototropism