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Plant Structure & Function
Mrs. Griffin
Photosynthesis Review
• Cross Section of Leaf
Photosynthesis Review
• Equation?– 6H2O + 6CO2 ----------> C6H12O6+ 6O2
• What do plants give us?
• Site for gas exchange?– Stomata
Light
Introduction to Plants
• Multicellular or unicellular?
• Carry out photosynthesis using the green pigments chlorophyll a and b
• What do plants need to survive?– Sunlight, H2O & minerals, gas exchange
movement of water and nutrients
Early Plants
• The first plants evolved from organisms much like the green algae living today– Photosynthetic pigments– DNA sequence, close relationship– Fossils- similarities to today's mosses
Bryophytes
• Mosses & their relatives are generally called bryophytes, or NON-VASCULAR, plants.
• Depend on water for reproduction
• Why non-vascular?
• Draw water up by
osmosisMosses, liverworts, hornworts
Seedless Vascular Plants
• Fossil evidence shows ~420 million years ago moss-like plants were joined w/ other plants species
• These new plants were the 1st to have a transport system w/ vascular tissue
• What is the function of vascular tissue?– Transport water & nutrients
Vascular Tissue• Tracheids are the key
cells in xylem, the transport system that carries water upward from roots
• Phloem, second vascular tissue that transports nutrients and carbohydrates produced by photosynthesis.
• Transpiration?
Seed Plants
• Over 1 million years plants with the capability to form seeds became the most dominant group of photosynthetic organisms on land.
Seed Plants
• Gymnosperms bear their seeds directly on the surface of cones
• Angiosperms, “flowering plants,” bear their seeds w/in a layer of tissue that protects the seed
Angiosperms: Flowers & Fruits
• Angiosperms, “enclosed seed,” develop unique reproductive organs known as flowers
• Flowers contain ovaries, which surround and protect the seeds
• Fruit- a wall of tissue surrounding the seed
Flowering Parts
Stamen
Petal
Style
Stigma
Sepal
Pistil
FilamentOvary
Ovules
Anther
Pollen
Diversity of Angiosperms
• Incredibly diverse group….
• Categories provide a way of organizing diverse angiosperms
• Two classes w/in angiosperms: monocotyledons (monocots) & dicotyledonae (dicots)
• Names for the number of seed leaves, or cotyledons in the plant embryo.
Diversity of Angiosperms
• Monocots have one seed leaf, and dicots have two
• Cotyledon is the 1st leaf or 1st pair of leaves produced by the embryo of a seed plant
Characteristics of Monocots & Dicots