1. LEC 09 FIELD BOTANY – Lecture 09 Dr. Donald P. Althoff Grasses Part I

2. Seed-bearing Flowers gymnosperms DICOTS MAGNOLIOPHYTA

3. Kingdom Division Class ORDERS - FAMILIES - Plantae Magnoliophyta (Anthrophyta) Liliopsida- moncots Cyperales 12 CyperaceaeJuncaceae 3 Juncales grassessedgesrushes

4. Grasses ______ diverse Grasses: 600 genera between ______________ speciesgeneraspecies Sedges: 70 genera ~4,000 speciesgeneraspecies Rushes: 8 genera ~400 speciesgeneraspecies

5. Grasslands of the world EQUATOR Tropic of Cancer Tropic of Capricorn

6. Historically, prairie covered 400,000 mi 2 of North America

7. ____ C 3 plants—all of carbon fixation and photosynthesis happens in _______________ just on the surface of the leaf. C 3 plants include most temperate plants (except many grasses)—more than _____ of all earth’s plants.

8. ____ C 4 plants—carbon fixation and photosynthesis split between the _____________________________________. Warm season grasses  _________ plant group in the short, mixed, and tallgrass prairies

9. Stomata, CO 2, & Fixation C 3 plants--uses the enzyme rubisco to fix carbon dioxide to RuBP…after fixation is PGAL, a _________________ C 4 plants--do not directly use Calvin cycle and produce immediately a _________________ ____ plants--uses PEP carboxsylase to fix CO 2 at night (example: cacti)

10. CAM Plants ____________________________ Fixation of CO 2 at night, stored in the form of malate in large vacuoles in the mesophyll cells is available the next day…. Stomata remained ______ during the day!!!

11. H2O H2O O2O2 CO 2 Calvin cycle

12.  3 carbon molecule Calvin cycle

13.  4 carbon molecule before Calvin cycle

14.  4 carbon molecule before Calvin cycle that is “banked” at night  Calvin cycle completed during the day Night Day

15. stoma ______ ______ cells Leaf Structure for ___ and ___ plants

16. Leaf Structure C 3 bundle sheath cells lack chloroplasts C 4 bundle sheath cells __________________ CAM _____________ in mesophyll cells

17. Enzyme utilized C 3 rubisco C 4 pepco CAM pepco

18. Optimum Temperature C 3 15 – 25 C__________ C 4 30 – 40 C__________ CAM 35 C__________

19. 0 5 10 15 20 25 30 35 40 32 41 50 59 68 77 86 95 104 oCoC oFoF C 3 Cool season C 4 Warm season CAM 15-25 o C 60-77 o F 30-40 o C 86-100 o F 35 o C * Approximate optimum (dark shades) and range (light shades) when C 3, C 4, and CAM plants start to grow/conduct photosynthesis efficiently

20. Growing season What do we mean “cool” vs. “warm” season? Peak period of plant productivity…and flowering cool warm J F M A M J J A S O N D F F F FFF F F F F

21. Productivity rate (tons/hectare/year) C 3 22 +/- 0.3 C 4 39 +/- 17 CAM low & variable

22. C 3 Plants - examples Peas Spinach Broccoli Kentucky bluegrass Tall fescue

23. C 4 Plants - examples Corn Soybeans Tomatoes Indiangrass Buffalo grass Big bluestem Blue grama

24. Adaptation to the Environment These 3 different “ways” (i.e., C 3, C 4, and CAM)to accomplish photosynthesis illustrate how organisms _________________ to their environment. Each has its advantages and disadvantages C 4 – likely _______ in high light intensity, high temperature, and limited rainfall environments. C 3 –likely _______ in lower light intensity, moderate temperature, and more abundant rainfall environments CAM – likely _______ in extremely arid environments (ferns and cone-bearing plants exhibit this process in addition to many flowering plants like some orchids and lily species)

25. Characteristics to note for GRASSES Inflorescences Spike vs. spikelets Ligule “design” (see _____________ set) Floret composition (palea, lemma, awns) Seed heads (panicle vs. spike) Fruits (are grains …compared to rushes and sedges )

26. _______________ = arrangement of flowers on the stem

27. Spike vs. ________

28. Seed heads: _______ vs. _______

29. SPIKELET FLORET seed palea lemma awn

30. FLORET SPIKELET awn lemma palea