plants as living organisms plant parts and their functions plant and soil science topic 2014
Post on 19-Dec-2015
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Root Functions
1. Anchor Plant 2. Absorb water and minerals 3. Translocate water and minerals to stem 4. Store Food
Root Parts
Primary root – First root that the seed sends out– Anchors root
Secondary root– Branches off of primary root
Root Cap– Protects roots while they grow
Root Parts
Root hairs: – Tiny one celled hair like extensions of the epidermal cells
located near the tips of the roots where vascular tissues have formed.
– Increase surface area– Absorb water and minerals from soilAdventitious rootsRoots that begin growth from the stem
Different type of Roots
A. Tap Root– Continuation of the primary root– Ideal for anchorage– Penetration is greater for water– Storage area for food made by photosynthesis
Different type of Roots
B. Fibrous Roots– Many finely branched secondary roots– Shallow roots cover a large area
More effective absorption of water and minerals Roots hold the soil to prevent erosion
Stem Function
1. Translocate water, minerals and food to the leaves
2. Support the leaves and display them to light
3. Store food and water
4. Produces new stem tissue
Stem Tissues
Xylem– Provide structural support– Transports water and minerals from roots to leaves
Phloem– Transports food made in leaves to the rest of the
plant
Buds
Bud scales– Protect under developed parts
Terminal Bud– Tip of twig
Apical Meristem– Primary growing point
Lateral buds– Can develop into secondary branches
Apical dominance– Hormones that prevent lateral buds from developing
Principal Tissues of the Leaf
Epidermis– Cuticle
Waxy substance covers the leaves and stems Waterproof layer that keeps water in plants
– Stomata Openings in the epidermis mainly located on underside of leaves Exchange of gases
– Guard Cells Two cells located on each side of stomata Open and closes stomata
Principal Tissues of the Leaf
Mesophyll layer– Palisade mesophyll
Primary site of photosynthesis– Spongy mesophyll
Contains air and chloroplasts Site of photosynthesis and gas exchange
Veins or vascular bundles– In spongy mesophyll– Phloem tissues conduct food from photosynthesis to rest of
plant– Xylem tissues conduct water and minerals up to cells in leaves
and stems
Simple vs. Compound
Simple – Single leaf blade and a petiole
Compound – A petiole and more then one leaf blades