Plant Dispersal and Reproduction

3. In free-sporing tracheophytes, the dispersal unit is the spore (e.g., Dryopteris spore above), which germinates into a gametophyte-- so the haploid stage is dispersed for these plants.

4. In the seed plants the sporophyte (embryo) is dispersed. So the diploid stage is dispersed for seed plants as in this rice seed above.

5. In this seed (Capsella sp.), note the three main parts of the embryo: • The epicotyl will become all of the above ground parts of the plant. • The hypocotyl will form the transition zone between the roots and the stem, • and the radicle will form all of the below ground parts of the plant. http://www.uwinnipeg.ca/~simmons/images/embryo3.gif

6. Coconut Fruit (a drupe=a fleshy indehiscent fruit with a seed enclosed in a stony endocarp) with its single seed in the center. Peaches and cherries are also drupes. www.botany.hawaii.edu/faculty/webb/BOT410/Angiosperm/CoconutDrawFruitsLab.jpg&imgrefurl=http://www.botany.hawaii.edu/faculty/webb/BOT410/Angiosperm/FruitCoconut.htm

7. Tissue from the megagametophyte Root End Cotyledons “Naked seed” e.g in this dissected Pinus sp. seed, note young sporophyte. http://botit.botany.wisc.edu/courses/Botany_130/Div/Phyla/Coniferophyta/Gymnosperm/Embryo.html

8. www.pioneer-net.com/psr/wallpaper.html Seeds Are Diverse www.prairiepoint.net/journal/images/P7200015.jpg http://natureproducts.net/Forest_Products/Trees/Sterculia%20brevissima%20seeds.jpg http://project.bio.iastate.edu/trees/campustrees/AcerSaccharu/AcerSacc_fruit.html

10. Equisetum and Psilotum are in the fern clade. (Pryer et al. 2001. Nature 409:618-622.) Leptosporangiate Ferns Ferns and Fern Allies “True Leaved Plants” Seed Plants Lycopods Mosses

12. CYCADS The basic growth form of a cycad is a central “trunk” with leaves spirally arranged at the top. http://www.damer.com/pictures/travels/southafrica/transvaal2.jpg helios.bto.ed.ac.uk/bto/microbes/nitrogen.htm

13. Cycads are dioecious and heterosporous Male Cone Cycas revoluta is dioecious Female Cone

14. The megasporophylls for Cycas is leaf-like with ovules at the base. The enlarged one has been fertilized and is developing into a seed

15. Male cones are also simple with each microsporophyll a modified leaf (forming a stalked peltate structure).

16. In Zamia the megasporophyll is highly reduced to a stalked, peltate-like structure. They are organized into a simple cone.

17. Cycadaceae Male cone and Cataphylls (a synapomorphy) of Cycas taitungensis (native to Taiwan) www.pacsoa.org.au/cycads/Cycas/taitungcone.jpg

18. Cycad Coralloid Roots (a synapomorphy of cycads) These roots grow up rather than down and can be seen above ground. They have symbiotic blue-green algae (see next slide) www.botany.hawaii.edu/.../LabsHTML-99/ Roots/LABROT12.jpg

19. Coralloid roots in Cycads Cross-section of coralloid root showing layer of blue-green algae (a nitrogen fixer). (Dioon spinulosum) Image from Wayne’s World

20. Ginkgo biloba -Maidenhair Tree Ginkgoaceae Note the dimorphic shoots-- short spur shoots and the long shoots bhort.bh.cornell.edu/conservatory/ gingko.jpg

21. Ginkgo Male Cone

22. Ginkgo ovules

23. Ginko sperm Multiflagellated Anterior position of flagella Pollination droplet on Ginkgo ovule. The droplet is repeatedly exuded and retracted. http://tokyocinema.net/E-ginkgo.htm

24. www.salisbury.edu/arboretum/ Ginkgo/GiBi/photos/GiBiSD01.JPG Ginkgos are widely planted in urban areas because they are resistant to pollution. They also have deciduous leaves that turn yellow before they drop. The fruits have an outer soft layer that has a powerful sewer-like smell. http://images.google.com/imgres?imgurl=ana.sote.hu/Gingko.jpg

25. www.ucmp.berkeley.edu/seedplants/ginkgoales/ovulesnleavessm2.jpgwww.ucmp.berkeley.edu/seedplants/ginkgoales/ovulesnleavessm2.jpg http://www.kikkoman.com/contents/cookbook/cook_img/G2.gif Once the outer soft layer and the hard layer are removed, the inner part of the Ginkgo seed can be eaten.

28. Pine Life Cycle - Monoecious, Heterosporous

29. Sporophyte, Monoecious simple male cone Scales have microsporangia on lower surface compound female cone Cells in the microsporangium undergo meiosis to form microspores (Pollen grains) Cone scales have 2 ovules on the upper surface. Microspores germinate into a male gametophyte One cell(megaspore mother cell) in the ovule undergoes meiosis. One meiotic product (haploid) survives. This is the megaspore. The megaspore develops into the female gametophyte

30. Pine Ovule sits on top of a cone scale and is a mix of sporophytic and gametophytic tissues

31. Pollen (microspore) lands on the ovule and germinates into a male gametophyte (pollen tube and associated cells) which carries the gametes to the archegonia which contains the egg. Pine ovule

33. Evolution of the female cone in the Pinaceae Cordaites extinct Lebachia extinct Pinus The ovule flips forward and the shoot, scales and bract fuse to form the cone scale. Dwarf shoots (d s) with ovules (o) and sterile scales (ss) all subtended by a bract (br).

34. Our focus is on 3 ( )of the 7 conifer (cone bearing) families Conifer Families

35. Pinaceae Pinus Picea Larix Abies Tsuga

36. www.wisc.edu/botit/img/bot/130/Gymnosperms/Coniferophyta%2520Images/Pinus%2520Images/Microsporangiate/pine%2520pollen%2520MC.jpgwww.wisc.edu/botit/img/bot/130/Gymnosperms/Coniferophyta%2520Images/Pinus%2520Images/Microsporangiate/pine%2520pollen%2520MC.jpg

37. Male cones are Simple.

38. Female cones are complex Pinus sp. The winged seed and the ovule opening towards the cone axis are both synapomorphies. The wing is derived from scale tissue. http://www.zoobotanica.u-net.com/GIF%20files/Botanical/pine.GIF

39. Close up of 2 ovules which open towards the cone axis (a synapomorphy) X-section of young female pine cone www.science.siu.edu/landplants/Coniferophyta/images/Pinus.female.cone.Sect.JPEG

40. Pine pollen (Microspore) Note:The “wings” are Actually air bladders which may facilitate wind dispersal or the pollination process itself. Tube nucleus Generative nucleus (will divide to form 2 sperm nuclei) www.wisc.edu/.../Microsporangiate/ pine%20pollen%20MC.jpg

41. Pine pollen grains viewed with fluorescent microscopy. You can see the bladders (“wings”) more easily than under conventional microscopy. micro.magnet.fsu.edu/.../gallery/ pinetreepollen.html

42. Range map in N.Am. Picea, the genus, is circumboreal and occurs as a co-dominant with firs (Abies spp.) in vast expanses of spruce-fir forests. Picea glauca White Spruce Pinaceae There are 35-40 species of Picea worldwide. Half are in China

43. Picea rubens Red spruce Pinaceae P. rubens is our Eastern species. It has small hairs on its branches. Its range extends south along the tops of the Appalachians. Locally it occurs on top of Mt. Greylock and the Dome. Range Map- note eastern distribution

44. Picea abies Norway Spruce Pinaceae An introduced European spruce widely planted on campus. Note large cones, upward sweeping branches and and droopy branchlets. It’s profile desingates it as a 60mph species!

46. Abies balsamea Balsam Fir Pinaceae Note: Upright cones with deciduous cone scales leaving upright “candles” and triangular profile. Range Map showing eastern distribution. Note there are 40 species of Abies worldwide (9 in the US). http://wiscinfo.doit.wisc.edu/herbarium/photos/ABIBAL_KKOHOUT.jpg

47. Larix laricina Larch Pinaceae Larix laricina is our only deciduous conifer. It has dimorphic shoots-- long and spur shoots.

48. Tsuga canadensis Hemlock Pinaceae Note droopy top (a 60mph characteristic), small hanging cones, row of leaves parallel to the stem axis.

49. Cupressaceae Thuja Juniperus

50. Juniperus communis, Common Juniper, Cupressaceae, female plant Junipers are dioecious.