An Introduction to Angiosperms: The Flowering Seed Plants

1. An Introduction to Angiosperms: The Flowering Seed Plants Biology 11

2. Seed Plants Vascular

3. Angiosperms- Flowering Plants • Phylum Angiosperma • The majority of plants alive today and the most diverse group

4. Characteristics • Vascular plants with stems, roots, leaves • Dominant generation= sporophyte • Flower =specialized structure for sexual reproduction • Pollen (dispersed by wind and insects) • Seeds are within the fruit • Angiosperm means “vessel seed”

5. Advantages for seeds being enclosed in fruits • Protection • Seed dispersal • Fruits (and seeds) are eaten by other organisms or attach (barbs) to other organisms for dispersal • Fruit decomposes and becomes nutrients for growing plant

6. Why are angiosperms more successful than gymnosperms in a land environment? • Angiosperm seeds are better protected • Angiosperms can go from seed to seed in less than one year as opposed to the years this may take in gymnosperms • The xylem cells in angiosperms are more efficient than in gymnosperms • Pollination is more successful • Can cross fertilize • Use insects to fertilize (more effective and direct)

7. Grouping Angiosperms There are many different ways to categorize angiosperms: • Woody and herbaceous plants • Annuals (lives for a year), biennials (lives for two years), perennials (lives longer than two years) • Monocots and dicots

8. Two subclasses: Monocots and Dicots • Named for the number of seed leaves (cotyledons) in the plant embryo • Angiosperm with 1 cotyledon = monocot • Angiosperm with 2 cotyledons = dicot

11. Angiosperm: Monocot • Seeds: • Embryo with single cotyledon • Flowers: • Flower parts in multiples of three • Leaves: • Linear; Major leaf veins are parallel • Vascular System of Stem: • Stem vascular bundles scattered • Vascular System of Roots: • Xylem and phloem alternate with one another in a circle Examples: Grass, palms, bamboo, lilies, orchids

12. Angiosperm: Dicot • Seeds: • Embryo with two cotyledons • Flowers: • Flower parts in multiples of four or five • Leaves: • Broad; Major leaf veins are netlike • Vascular System of Stem: • Stem vascular bundled in a ring • Vascular System of Roots: • Xylem arranged in X in middle of root, phloem in between arms of X Examples: Woody plants, shrubs, trees (excluding conifers), cacti

13. Angiosperms Reproduction

14. Angiosperm seeds are contained within protective wall that develops into a fruit • Pollination brings pollen to the ovary which develops into a seed

15. Structure of Flower (♀) Pistil Stigma Style Ovary Ovule Petal Anther Filament Sepal (♂) Stamen Stem (receptacle)

16. Sepals • Outermost circle of flower parts • Enclose flower bud before it opens and protects the flower while it develops • Some flowers it is green, in others it’s the same colour as the petals • All sepals together called the calyx

17. Petals • Make up the second circle of flower parts • Often brightly coloured • All petals together form the corolla

18. Pistil • Female part of the flower (inner most) • Made of 3 parts: • Stigma • Style • ovary

19. Stigma • Stigma- surface upon which pollen is deposited by wind or animals • Often sticky

20. Style • Stalk that connects the stigma and ovary

21. Ovary • Contains the ovules which (when fertilized) becomes the seed

22. Stamen • Male part of the flower • Made up of 2 parts: • Anther- makes and releases pollen • Filament- holds up the anther

23. Sexual Reproduction • Within the ovary you will find ovules. • The ovules contain a mother cell (2N). Through meiosis will produce haploid megaspores (1N). • Three of the four megaspores die. • 1 remaining megaspore, through mitosis produces egg cell and two polar nuclei (found in central cell)

25. Sexual Reproduction • Within anther are 4 pollen sacs • Mother cells undergo meiosis to produce haploid microspores (N) • Microspore divide by mitosis to produce pollen grains (produced in large numbers)

26. Sexual Reproduction- Pollination • Pollination- The transfer of pollen grains from the anther to the stigma

27. Wind-pollinated Plants • Pollen grains fall and carried by wind • Flowers are small and plain with little fragrance

28. Bee-pollinated • Don’t see red • See yellow, blue, green and UV light best • Some flowers have UV markings only bees can see • UV colors and patterns in petals announce the flower’s nectar and pollen

29. Bird Pollination • Birds often pollinate red flowers • Animal pollinators have coevolved with plants

30. Hammer Orchid

32. Fertilization • Once pollination has taken place a pollen tube will germinate on the stigma • The pollen tube grows down the style and enters the tip of the ovule through the micropyle • Male gametes move through pollen tube towards the egg cell

33. Double Fertilization • One sperm cell fuses with egg (fertilization) and results in the formation of a diploid zygote • A second sperm fuses with two polar nuclei which results in a triploid (3N) endosperm • The endosperm provides nutrients (starch) and surrounds the developing embryo

35. Fruits • After fertilization occurs the ovary walls develop into a fruit • The fruit protects the seeds from desiccation and assists in their dispersal

36. Types of Fruit • Fleshy fruits (peach, cucumber, apples, tomato) • Dry fruit (hazelnut, peanuts, walnuts) • Accessory fruit- not from ovary (strawberry, pineapple)

38. Kopi Luwak

39. Seed Dispersal • Reduces competition for sunlight, soil, and water between parent and developing plant

40. Germination • Occurs when an embryo in a seed develops • Triggered by favourable conditions, absorption of water, and oxygen.

41. First part to emerge is the radicle • Becomes root • The hypocotyl is the first part of the plant to push through soil • The hypocotyl straightens out and the epicotyl will emerge • Plants first leaves emerge

42. Complete Flower Worksheet • Tomorrow: Flower (Dissection!) Lab • Thursday: Angiosperm Quiz • Thursday May 8 Plant Unit Test