The Plant Kingdom

1. The Plant Kingdom • Origins 500- 475 MYA • 10 Phyla • 4 Basic lifecycles • Green algae that evolved onto land • Evolved becoming more terrestrial, independent from water • Then coevolved with pollinators, dispersal

2. Tentative Phylogeny Fig 28.8

3. An overview of land plant evolution Land plants Vascular plants Bryophytes (nonvascular plants) Seedless vascular plants Seed plants Mosses Hornworts Liverworts Angiosperms Gymnosperms Charophyceans Pterophyte (ferns, horsetails, whisk fern) Origin of seed plants (about 360 mya) Lycophytes (club mosses, spike mosses, quillworts) Origin of vascular plants (about 420 mya) Origin of land plants (about 475 mya) Ancestral green alga Figure 29.7

4. Lab • Chara Lifecycle • Moss Lifecycle • Liverworts • Fern Lifecycle • Lycophytes

5. Charophyceans- plant’s green algae ancestor Chara - 30 Coleochaete- 31 Modern examples of charophyceans

6. Chara sp. (green algae)

8. Chara Slide #30 Oogonia Antheridia

9. Chara sp. Oogonia Antheridia

10. Alternation of Generations • Separate multicellular haploid and diploid phases • (2n) Sporophyte make spores by meiosis • (n) Gametophyte makes gametes by mitosis • Sperm and egg (moss & fern) • Pollen and Ovule (gymnosperm & angiosperm) • The sporophyte and gametophyte are very different in morphology • Vascular tissues only appear in sporophyte phase • Sporophyte becomes more dominant in new plant groups • Charophyceans lack sporophyte phase

12. Characteristics that Plants share with the green algae group Charophyceans • Autotrophic Multicellular Eukaryote • Have cell walls made of cellulose • Made by rosette cellulose-synthesizing complexes • 20-26% of wall material, closest match in algae • Chloroplast similarities • have chlorophyll a & b, use β-carotene as accessory • Thylakoids stacked in grana • Chloroplast DNA comparisons

13. Characteristics that Plants share with the green algae group Charophyceans • Peroxisome enzymes • Cell plate formation by phragmoplast • Nuclear membrane breaks down during mitosis • Sperm ultrastructure - biflagellate • Gene sequences – rRNA, Cytoskeleton proteins

14. Switch to sporophyte dominance

15. What’s new in Mosses?( Derived Traits) • Spores / sporangia • Sporophyte phase • Upright growth on land • Cuticle • Multicellular gametangia

16. The Bryophytes • Bryophytes are represented by three phyla: • Division Hepatophyta - liverworts • Division Anthocerophyta - hornworts • Division Bryophyta – mosses Liverworts and hornworts are believed to be more similar to what early plants were like.

17. Bryophyte lifecycle: moss • Haploid dominant • No vascular tissues • Filamentous protonema stage • Swimming sperm • Disperse by spores • Dependent sporophyte • Dioecious gametophytes • No true leaves • Rhizoids, not roots

18. Pteridophytesevolved over 400 MYA Seedless, Vascular plants (having Xylem & Phloem). Today represented by two phyla: Pterophyta: Ferns, Horsetails (Equisetum) Lycophyta: Club moss Cooksonia, an extinct plant over 400 million years old, is the earliest known vascular plant.

20. Protonema

21. Protonema - #32

22. Moss Antheridia

23. Antheridia on stalk

24. Moss Antheridia # 33

25. Moss Archegonia

26. Moss Archegonia #34

27. Moss Archegonia #34

28. Moss Sporangia

29. Moss Sporangia- 35

30. Moss Sporangia- # 35

31. An overview of land plant evolution Land plants Vascular plants Bryophytes (nonvascular plants) Seedless vascular plants Seed plants Mosses Hornworts Liverworts Angiosperms Gymnosperms Charophyceans Pterophyte (ferns, horsetails, whisk fern) Origin of seed plants (about 360 mya) Lycophytes (club mosses, spike mosses, quillworts) Origin of vascular plants (about 420 mya) Origin of land plants (about 475 mya) Ancestral green alga Figure 29.7

32. Spores WALLED SPORES PRODUCED IN SPORANGIA Sporangium Longitudinal section of Sphagnum sporangium (LM) Sporophyte and sporangium of Sphagnum (a moss) Sporophyte Gametophyte MULTICELLULAR GAMETANGIA Female gametophyte Archegonium with egg Antheridium with sperm Archegonia and antheridia of Marchantia (a liverwort) Male gametophyte MULTICELLULAR, DEPENDENT EMBRYOS Embryo Maternal tissue 2 µm Embryo and placental transfer cell of Marchantia 10 µm Wall ingrowths Placental transfer cell

33. Liverwort Gametophyte

36. Female Gametophyte

37. Liverwort Antheridia • Antheridia are on the upper surface of the “umbrellas”

38. Liverwort Antheridia

39. Liverwort Archegonia • Archegonia are on the undersides of the “umbrellas”

40. Liverwort Archegonia

41. Liverwort Archegonia - egg

42. Liverwort Sporangia • On undersides- develop from archegonia

43. Gemmae & cups

44. Gemmae & cup

46. An overview of land plant evolution Land plants Vascular plants Bryophytes (nonvascular plants) Seedless vascular plants Seed plants Mosses Hornworts Liverworts Angiosperms Gymnosperms Charophyceans Pterophyte (ferns, horsetails, whisk fern) Origin of seed plants (about 360 mya) Lycophytes (club mosses, spike mosses, quillworts) Origin of vascular plants (about 420 mya) Origin of land plants (about 475 mya) Ancestral green alga Figure 29.7

47. Vascular tissue • Allows plants to grow taller • More support by lignified xylem tracheids • Can pull water up from soil • Can tolerate soil that is drier on the surface • Form parts of true leaves and roots. • Only found in diploid tissue • Lead to sporophyte dominance?

48. Fern Lifecycle • Diploid dominate • Gametophyte still independent, short lived, • monoecious in fern (Pteridophyta) • dioecious in club “moss” (Lycophyta) • Spores disperse plant • Sporophyte perennial

49. Pteridophytesevolved over 400 MYA Seedless, Vascular plants (having Xylem & Phloem). Today represented by two divisions: Pterophyta: Ferns, Horsetails (Equisetum) Lycophyta:Club moss Cooksonia, an extinct plant over 400 million years old, is the earliest known vascular plant.