Weed Biology and Identification-203 Target students: M.Sc. Students in Weed Science Lecture: Dr....
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Transcript of Weed Biology and Identification-203 Target students: M.Sc. Students in Weed Science Lecture: Dr....
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 [email protected]
1
Plant Parts
Chapter #3
Modified by Georgia Agriculture Education Curriculum Office
June 2002
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)
What are the parts of a plant?
Epicotyl: all of plant formed above cotyledonary node
Internode: stem tissue between nodes
What are the types of stems?
1) Woody Stem: trees, shrubs, woody perennials
2) Grass Stem: hollow or filled3) Herbaceous Stem: like
woody but softer (clover, alfalfa)4) Modified Stem:
Types of Modified Stems
• Bulbs: (onion)• Tubers: (potato)• Stolons: above ground runner (strawberry)• Rhizomes: below ground runners (field
bindweed or creeping jenny)
What are the functions of stems?
1) transport water, nutrients, sugars
2) support leaves3) store food
What are buds?
• special tissue on stems that can grow into new plant parts
• buds are described according to:
• 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
Bud Arrangements
–Alternate (alfalfa)–Opposite (beans)–Whorled (not common)
What is Apical Dominance?
• apical bud tries to make plant grow taller or longer
• if we remove apical bud, we remove the apical dominance
What are leaves?
• undergo photosynthesis, exchange gases
What is the difference between a simple leaf and a compound leaf?
• simple leaf = 2 parts (leaf blade and petiole)
Petiole
Leaf
Blade
What is the difference between a simple leaf and a compound leaf?• Compound leaf: leaf blade divided into
leaflets
What are the different types of compound leaves?
• Palmately compound
What are the different types of compound leaves?
• Pinately compound
What are the different types of compound leaves?
• Trifoliate (alfalfa)
What is the Hypocotyl?
• part of the plant below the cotyledonary node
What purpose does the hypocotyl serve?
1) anchor plant
2) absorb water & nutrients
3) store food
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)
To help prevent soil erosion, which root system would be best?
• Fibrous
What are the parts of a grass plant?
• Leaves = Sheath is the part of leaf that wraps around the stem
• Joints = internodes• Culm = stems
Grass Plant Parts
• Tillers = branches, all branch from the base of the plant
• Crown = union of roots and stem
• Jointing stage = stems elongate rapidly