1. Weed Biology and Identification-203 Target students: M.Sc. Students in Weed Science Lecture: Dr. Majid AghaAlikhani (Ph.D.) Academic position : Associate Prof. of Tarbiat Modares University maghaalikhani@modares.ac.ir 1

2. Plant Parts Chapter #3 Modified by Georgia Agriculture Education Curriculum Office June 2002

3. What are the parts of a plant? Node: swollen part of stem where buds form (leaves or stems grow here) Cotyledons: leaves formed at first node (cotyledonary node)

4. What are the parts of a plant? Epicotyl: all of plant formed above cotyledonary node Internode: stem tissue between nodes

5. What are the types of stems? 1) Woody Stem: trees, shrubs, woody perennials 2) Grass Stem: hollow or filled 3) Herbaceous Stem: like woody but softer (clover, alfalfa) 4) Modified Stem:

6. Types of Modified Stems Bulbs: (onion) Tubers: (potato) Stolons: above ground runner (strawberry) Rhizomes: below ground runners (field bindweed or creeping jenny)

7. What are the functions of stems? 1) transport water, nutrients, sugars 2) support leaves 3) store food

8. What are buds? special tissue on stems that can grow into new plant parts buds are described according to:

9. 1) structures into which they grow –-Vegetative: leaves or stems –-Floral: flowers –-Mixed: both 2) where buds appear on stem –-Apical: tips of stems -if floral = bush -if vegetative = vine –-Axillary: where leaf joins stem –-Adventitious: near wounds 3) How buds are arranged

10. Bud Arrangements –Alternate (alfalfa) –Opposite (beans) –Whorled (not common)

11. What is Apical Dominance? apical bud tries to make plant grow taller or longer if we remove apical bud, we remove the apical dominance

12. What are leaves? undergo photosynthesis, exchange gases

13. What is the difference between a simple leaf and a compound leaf? simple leaf = 2 parts (leaf blade and petiole)

14. What is the difference between a simple leaf and a compound leaf? Compound leaf: leaf blade divided into leaflets

15. What are the different types of compound leaves? Palmately compound

16. What are the different types of compound leaves? Pinately compound

17. What are the different types of compound leaves? Trifoliate (alfalfa)

18. What is the Hypocotyl? part of the plant below the cotyledonary node

19. What purpose does the hypocotyl serve? 1) anchor plant 2) absorb water & nutrients 3) store food

20. What are the types of root systems? -Taproot: one main root, has no nodes –(carrot, evergreen, kochia) -Fibrous root: many nodes, branching root system (grasses)

21. To help prevent soil erosion, which root system would be best? Fibrous

22. What are the parts of a grass plant? Leaves = Sheath is the part of leaf that wraps around the stem Joints = internodes Culm = stems

23. Grass Plant Parts Tillers = branches, all branch from the base of the plant Crown = union of roots and stem Jointing stage = stems elongate rapidly