1. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PLANTS

2. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Plants are multicellular photosynthetic eukaryotes –They share many characteristics with green algae –However, plants evolved unique features as they colonized land What is a plant?

3. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PLANT LEAF performs photosynthesis CUTICLE reduces water loss; STOMATA allow gas exchange STEM supports plant (and may perform photosynthesis) Surrounding water supports the alga ALGA WHOLE ALGA performs photosynthesis; absorbs water, CO 2, and minerals from the water HOLDFAST anchors the alga ROOTS anchor plant; absorb water and minerals from the soil (aided by mycorrhizal fungi)

4. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Unlike algae, plants have vascular tissue –It transports water and nutrients throughout the plant body –It provides internal support

5. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Two main lineages arose early from ancestral plants Plant diversity provides clues to the evolutionary history of the plant kingdom

6. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PALEOZOIC Radiation of flowering plants MESOZOIC CENOZOIC Charophyceans (a group of green algae) Bryophytes (e.g., mosses) Seedless vascular plants (e.g., ferns, horsetails) Gymnosperms (e.g., conifers) Angiosperms First seed plants Early vascular plants Origin of plants

7. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings One lineage gave rise to bryophytes –These are plants that lack vascular tissue –Bryophytes include mosses, which grow in a low, spongy mat

8. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vascular plants are the other ancient lineage Ferns and seed plants were derived from early vascular plants and contain –xylem and phloem –well-developed roots –rigid stems

9. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PARTS OF A VASCULAR PLANT

10. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ferns are seedless plants whose flagellated sperm require moisture to reach the egg

11. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A major step in plant evolution was the appearance of seed plants –Gymnosperms –Angiosperms These vascular plants have pollen grains for transporting sperm They also protect their embryos in seeds

12. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Gymnosperms, such as pines, are called naked seed plants –This is because their seeds do not develop inside a protective chamber The seeds of angiosperms, flowering plants, develop in ovaries within fruits

13. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PLANT TISSUES

14. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Angiosperms, or flowering plants, are the most familiar and diverse plants There are two main types of angiosperms –Monocots include orchids, bamboos, palms, lilies, grains, and other grasses –Dicots include shrubs, ornamental plants, most trees, and many food crops The two main groups of angiosperms are the monocots and the dicots PLANT STRUCTURE AND FUNCTION

15. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Monocots and dicots differ in seed leaf number and in the structure of roots, stems, leaves, and flowers SEED LEAVESLEAF VEINSSTEMSFLOWERSROOTS MONOCOTS One cotyledon Main veins usually parallel Vascular bundles in complex arrangement Floral parts usually in multiples of three Fibrous root system Two cotyledons Main veins usually branched Vascular bundles arranged in ring Floral parts usually in multiples of four or five Taproot usually present DICOTS

16. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Root system –Provides anchorage –Absorbs and transports minerals and water –Stores food Root hairs increase the surface area for absorption The plant body consists of roots and shoots

17. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Shoot system –Consists of stems, leaves, and flowers in angiosperms –Stems are located above the ground and support the leaves and flowers –Leaves are the main sites of photosynthesis in most plants

18. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PARTS OF A FLOWERING PLANT

19. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The terminal bud is located at the tip of a stem –It is the growth point of the stem Axillary buds can give rise to branches In apical dominance, the terminal bud produces hormones that inhibit the growth of axillary buds –This results in a taller plant that has greater exposure to light

20. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Roots and stems are adapted for a variety of functions –Storing food –Asexual reproduction –Protection Plant breeders have improved the yields of root crops by selecting varieties, such as the sugar beet plant, with very large taproots Many plants have modified roots and shoots

21. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Modified stems include –runners, for asexual reproduction –rhizomes, for plant growth and food storage –tubers, for food storage in the form of starch STRAWBERRY PLANT POTATO PLANT IRIS PLANT Runner Tuber Taproot Rhizome Root

22. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Modified leaves include tendrils and spines –Tendrils help plants to climb –Spines may protect the plant from plant-eating animals

23. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings NUTRITION

24. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings ELEMENTS NEEDED IN PLANT NUTRITION

25. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

26. GROWTH REGULATION

27. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Light is central to the life of a plant Photosynthesis is the most important chemical process on Earth –It provides food for virtually all organisms Plant cells convert light into chemical signals that affect a plant’s life cycle Life in the Sun

28. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Light can influence the architecture of a plant –Plants that get adequate light are often bushy, with deep green leaves –Without enough light, plants become tall and spindly with small pale leaves Too much sunlight can damage a plant –Chloroplasts and carotenoids help to prevent such damage

29. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Photosynthesis is the process by which autotrophic organisms use light energy to make sugar and oxygen gas from carbon dioxide and water AN OVERVIEW OF PHOTOSYNTHESIS Carbon dioxide WaterGlucoseOxygen gas PHOTOSYNTHESIS

30. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Plants, some protists, and some bacteria are photosynthetic autotrophs –They are the ultimate producers of food consumed by virtually all organisms Autotrophs are the producers of the biosphere

31. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings On land, plants such as oak trees and cacti are the predominant producers

32. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In aquatic environments, algae and photosynthetic bacteria are the main food producers

33. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In most plants, photosynthesis occurs primarily in the leaves, in the chloroplasts A chloroplast contains: –stroma, a fluid –grana, stacks of thylakoids The thylakoids contain chlorophyll –Chlorophyll is the green pigment that captures light for photosynthesis Photosynthesis occurs in chloroplasts

34. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The location and structure of chloroplasts LEAF CROSS SECTION MESOPHYLL CELL LEAF Chloroplast Mesophyll CHLOROPLAST Intermembrane space Outer membrane Inner membrane Thylakoid compartment Thylakoid Stroma Granum StromaGrana

35. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Are plants useful to man?

36. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings How are plants useful to man? List the ways you use plants everyday.

37. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings We eat plants for breakfast, lunch and dinner. What plants have you eaten today?

38. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings We use plants to make our clothing.

39. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings We use plants to make medicines.

40. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings We use plants to build furniture and buildings.

41. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Plants are useful in cleaning the air we breathe.

42. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Man is very dependent on plants.