1. SEED PLANTS II
The Flowering Plants (Anthophyta)

2. Anthophyta

3. Phylum Anthophyta (Angiosperms)
Constitutes ~300,000 species (Gymno. 720 spp)
Most recently evolved & most diverse group
Divided into many groups:
Basal Angiosperms
Magnoliids (~8500)
Eudicotyledones (dicot)
Monocotyledones (monocot)
Most living vascular plants are angiosperms
Angiosperms are characterized by a unique organ system called the flower
It seems like each of the mono and the eudicots is a monophyletic group

4. Phylogeny of Angiosperms
Basal angiosperms
Each branch of the tree can be called a clade or lineage.
Amborella is considered an intermediate between Gymnosperms and Angiosperms. It consists of one species in New Caledonia. This is a shrub with small flowers and lacks vessels (has only tracheids).
The early (basal) angiosperms have alternate and simple leaves, flowers with multiple whorls of tepals ( a common term for sepals and petals when they look alike), stamens are undifferentiated into filaments and anthers), and many separate carpels. Also carpels are not completely closed. Amborella and Nymphaeales lack vessels, Austroballeyales has simple vessel.
Carpel is a modified leaf that protects ths developing seed. It includes the stigma, style and an ovary.
Fusion

5. Fusion of Carpel
secretion
fusion
From Endress & Igersheim, 2000

6. Characteristics of Angiosperms
Double fertilization:
egg + sperm produce zygote (2n)
egg + 2nd sperm produce endosperm (3n)
Mostly closed carpels: enclose ovule
Reduced gametophytes (pollen grain, embryo sac)
Sieve tubes and companion cells (phloem)
Vessels (xylem)
Stamens with 2 pairs of pollen sacs
Chemical evolution!

7. Refinements in vascular tissue, especially xylem, probably played a role in the enormous success of angiosperms in diverse terrestrial habitats.
Like gymnosperms, angiosperms have long, tapered tracheids that function for support and water transport.
Angiosperms also have fiber cells, specialized for support, and vessel elements (in most angiosperms) that develop into xylem vessels for efficient water transport.

8. Amborella (Basal angiosperms)
Fruit
Scott Zona
Notice the female flowers have 0-several stamenoids (sterile stamens). This is a genus of one species native to New Caledonia (an Island E of Australia)
Scott Zona
The plant is dioecious. Female flowers with 5-6 carpels (a). Male flowers stamens (b).

9. Magnolia (Magnoliids)
Follicle is a dehiscent fruit from a single carpel.
Fruit: aggregate follicle

10. Tulip (Magnoliids)

11. Differences Between Monocot & Eudicot
Embryo with single cotyledon
Pollen with a single furrow or pore*
Flower parts in multiples of three
Major leaf veins parallel
Stem vascular bundles scattered
Have fibrous roots
Secondary growth absent
EUDICOT
Embryo with two cotyledons
Pollen with three furrows or pores
Flower parts in multiples of four or five
Major leaf veins reticulate
Stem vascular bundles in a ring
Have taproots
Secondary growth often present
Fibrous roots: many small roots of same size originate from the base of monocot stem because their primary root is short-lived.
Taproot: the main embryonic root giving rise to smaller later roots as in dicot
Adventitious root: roots from places other than root
Magnoliids have pollen like Monocot

12. Pollen of Horse chestnut
Eudicot like these have pollen with 3 apertures
A Grass Pollen
Pollen of Horse chestnut

13. Flower: the main feature of angiosperms
(= Carpel)

14. The Flower Perianth: Sepals & petals collectively
Androecium: stamens collectively
Gynoecium: pistils collectively

15. Types of Flowers Complete flower: has all 4 floral parts
Incomplete flowers: missing a floral part(s)
Perfect Flower: bisexual
Imperfect flower: unisexual flowers
Staminate flowers: have only the stamens
Pistillate (carpellate) flowers: have only pistils
Monoecious plants: separate staminate and pistillate flowers on the same plant
Dioecious plants: either staminate or pistillate flowers
Monoecious: (grasses)
Dioecious (willows)

16. Zygomorphic: floral parts are different (bilaterally symmetrical)
Floral symmetry:
Actinomorphic flower: floral parts are of similar shape & size (radially symmetrical)
Zygomorphic: floral parts are different (bilaterally symmetrical)
Inflorescence: A cluster of flowers with a definite arrangement
Fertilization: the fusion of two gamete nuclei to produce a diploid zygote
Pollination: transfer of pollen from the anther to the stigma
Pollen transferred within the same flower is called self-pollination, and the species is an in-breeder
Pollen transferred to a different flower is called cross-pollination and the species is out-breeder

17. Example of Monocot Flower: Lilium sp.

18. Example of a Dicot Flower
Hibiscus moscheutos

19. Dicot
Stamens
H. moscheutos is a Dicot, with five petals and five sepals.
It grows naturally in cattail marshes along the shore of Lake Ontario and along the Hudson River between Albany and New York City.
The showy pink petals are ten or more centimeters long.
The style divides into five branches near its tip; each branch bears a capitate (hear-like) stigma
It is a member of the Mallow Family (Malvaceae)
As with all members of the Malvaceae, the numerous stamens are fused by their filaments to form a tube around the style.
Stigmas

20. Hibiscus II Filament tube Style Ovary Ovules
A flower has been split open to show the ovary with ovules contained inside
The flower remains open for only one day
After the corolla, stamens, and style wither and fall away, the ovary develops into a capsule that splits open to release the seeds.

21. Angiosperm Life Cycle Sperm Egg Fertilization 1n 2n Zygote Meiosis
Pollen
Embryo sac
Megagametogenesis
Microgametogenesis
Sperm
Egg
Fertilization
Microspores
Megaspores
Micosporogenesis
Megasporogenesis 1n 2n
Zygote
Meiosis
Sporophyte

22. Development of Pollen
Microsporogenesis: the development of microspore mother cell (microsporocyte) into microspores
This involves meiosis

23. Liliy Flower

24. Microsporocytes
Microsporocyte is a single diploid cell (2n) that undergoes meiosis to produce 4 haploid cells (microspores or male spores)
Tapetum is the non-reproductive tissues that provide nutrition to the developing spores

25. Microsporocyte undergo Meiosis
The microspore mother (2n) cells undergoing meiosis. See cells in various stages of meiosis.

26. Tetrads of Microspores
Pollen tetrads
Microspores
At end of meiosis 4 haploid (1n) male spores are produced
4 microspores were produced by meiosis
Microsporogenesis is complete

27. Development of Pollen
Microgametogenesis: the development of microspores into male gametophyte (pollen grain)
This involves mitosis

28. Mature Male gametophyte
Microspores underwent mitosis to produce male gametophytes

30. Mature Pollen grain The tube nucleus produced the pollen tube
The generative cell produced two sperm nuclei

31. Development of Female Gametophyte
Megasporogenesis: the megasporocyte (megaspore mother cell) develops into megaspores by meiosis

32. Lilium Ovary
Cross section of lilium ovaries.

33. Megasporocyte Before Meiosis
The Megasporocyte or megaspore mother cell is a single diploid cell (2n) which undergoes meiosis to produce 4 haploid cells (megaspore or female spores).

34. Two-nucleate Stage (formed by meiosis)

35. Four-nucleate Stage (formed by meiosis)
This survives others die
The result of meiosis is 4 haploid cells. Only one of these cells survives. In the next slide you would see the surviving female spore

36. Functional Megaspore Megasporogenesis is complete
This is the megaspore or the female spore (1n) which develops into the female gametophyte (by mitosis). See next sildes.

37. Development of Female Gametophyte
Megagametogenesis: the megaspore develops into mature female gametophyte (embryo sac) by mitosis
Three mitotic divisions follow

38. First mitotic Division: 2-nucleate embryo sac

39. 2nd Mitotic Division: 4-Nucleate embryo sac

41. 3rd Mitotic Division: 8-Nucleate embryo sac

42. 8-Nucleate embryo sac
2 of 4 Antipodals
Egg & 2 synergids

43. Pollination & Fertilization
Pollen Tube
Sperms
Pollination & Fertilization

44. Double Fertilization