1. Chapters 22-25 Plants

2. Characteristics  Eukaryotes  Multicellular  Cell walls of cellulose  Carry out photosynthesis using pigments chlorophyll a and b  Life cycle  Gametophyte (1N) > gametes (1N) > fertilization > zygote > sporophyte (2N) > meiosis > spores (1N) > mitosis > gametophyte  Evolved from green algae

3. 3 Types of Tissues  Dermal tissue – outer covering  In leaves covered by cuticle – waxy layer  Vascular tissue – conducts nutrients through plant  Xylem – conducts water  Composed of dead cells called tracheids and vessel elements that act as pipes.  Phloem – conducts food  Composed of sieve tube elements – contain openings to allow sugars through  Also, companion cells – surround for support  Ground tissue – btw others  Parenchyma – site of most photosynthesis  Collenchyma – flexible walls, help support – celery  Sclerenchyma – thick, rigid, strong

4. Structure I  Roots – underground organs that absorb water and minerals, anchors, prevents erosion  2 types  Taproot – 1 main root – carrots  Fibrous roots – many similar branches  Structure  Epidermis – outer layer  Covered in root hairs – increase surface area for absorption  Cortex – middle – ground tissue  Endodermis – inner  Aka vascular cylinder  Contains xylem & phloem  Root cap – covers apical meristem

5. Structure II  Leaves – bundles of photosynthetic vascular tissue  Structure  Blades – flattened section  Petiole – attaches to stem  Specialized ground tissue  Palisade mesophyll – absorbs light  Spongy mesophyll – connects to the outside via stomata (openings) to allow carbon dioxide in and oxygen out  Guard cells – control opening/closing of stomata  Functions  Photosynthesis  Transpiration – loss of water through leaves  Gas exchange

6. Structure III  Stem  3 functions  Produce leaves, branches, & flowers  Hold leaves up to sunlight  Transport substances between roots and leaves  Structure  Nodes – where leaves attach  Internode – region btw nodes  Buds – at nodes – tissue that can produce new stems and leaves  Primary growth – occurs in meristematic tissue at the apical meristem – increase in length  Secondary growth – increase in width  Occurs in lateral meristematic tissue – vascular cambium & cork cambium

7. Classification I  Bryophytes  3 phyla  Vascular tissue absent – results in small size  Flagellated sperm - must stay close to water  No true roots or leaves  Gametophyte - dominant life cycle  Ex. Mosses, liverworts, hornworts

9. Classification II  Pteridophytes  2 phyla  Vascular tissue present  Appearance of true roots & leaves  Sporophyte – now the dominant life cycle  Ex. Ferns, club mosses, horsetails

11. Classification III  Gymnosperms  Appearance of seeds (embryo of a plant encased in a protective covering with a food supply) which are produced in cones - plants were able to reproduce without water  Male gametophyte – pollen  Ex. Gnetophytes, Cycads, Ginkgoes  Conifers – pine, juniper, spruce  Aka evergreens

12. Classification IV  Angiosperms  Aka flowering plants  Cotyledons – embryonic seed leaves  Monocots – 1 seed leaf, parallel veins  Vascular bundles in stem are scattered  Dicots – 2 seed leaves, branched veins  Vascular bundles in stem are arranged in a ring  May be subdivided based on stem characteristics  Woody or Herbaceous  Life spans  Annuals - complete a life cycle 1 year  Biennials - complete a life cycle in 2 years  Perennials - live for more than 2 years

13. Alternation of Generations  Gametophyte (1N) > gametes (1N) > fertilization > zygote (2N) > sporophyte (2N) > meiosis > spores (1N) > gametophyte  Gymnosperms  Gametophytes are found in cones  Pollen cones – male  Ovulate cones – female  Pollen is carried by wind from male to female

14. Alternation of Generations  Angiosperms  Gametophytes are found in flowers  Structure  Sepals - outermost petals – green – enclose bud before opening  Petals - brightly colored – attract pollinators  Stamen  Filament - thin stalk  Anther - produce male gametophytes (pollen)  Pistil  Aka carpel  Stigma - top – sticky  Style – stalk  Ovary - contains female gametophytes – becomes fruit  Life cycle – Double Fertilization  Pollen sticks to stigma  Pollen tube forms and grows down style to ovary  1 sperm fertilizes egg = embryo  A 2 nd sperm joins with other cells to form the endosperm (food supply)

15. Angiosperm life cycle

16. Flowers  Sepal  Petals  Stamen  Anther  Filament  Carpel  Stigma  Style  Ovary

17. Pollination

18. Seed Dispersal  May be dispersed by wind, water, or animals  May remain dormant until conditions are right  Germination – early stage of growth

19. Plant Hormones  Hormone – chemical substance that control’s a plants growth, development, and responses  Target cell – part affected by a particular hormone  Auxins cause:  Phototropism – growth toward light  Gravitropism – causes branches to grow up and roots to grow down  Apical dominance - delays the appearance of new lateral buds (which grow into side branches)  Cytokinins - stimulate cell division, growth of lateral buds, and sprouting  Gibbreellins - promotes overall growth  Ethylene - stimulates fruits to ripen

20. Plant responses  Tropisms – response to an external stiumulus  Types  Gravitropism - response to gravity  Phototropism - response to light  Thigmotropism – slower changes in growth in response to touch  Vines  Rapid responses – quick movement in response to touch  Mimosa, venus fly trap

21. Photoperiodism  Timing of seasonal activities  Phytochrome - pigment responsible  Short-day plants - flower when days are short  Ex. Poinsettias  Long-day plants - flower when days are long  Dormancy - period when growth/activity decrease or stop  Usually during winter for deciduous plants