Multicellular autotrophic eukaryotes
Plant Characteristics
Cell walls with cellulose
Chloroplasts containing chlorophylls a and b
Store food as starch
Challenges to Plant Life
Obtaining materials needed for life
light
water
carbon dioxide
minerals
Bringing gametes together for reproduction
Dispersing offspring
Supporting the body
Ultraviolet light
Temperature
Adaptations to Land
Cuticle: Waxy layer that prevents water loss.
Stomata: openings usually found on the underneath sides of leaves. Used in gas exchange. Two sausage shaped guard cells surround each opening.
Vascular tissues: allow transport of nutrients. Tissue that forms vessels.
Xylem: transports water up from the roots.
Phloem: transports food down from the leaves.
Seed Dispersal
Plant Types
Non-vascular plants
Dominant gametophyte (haploid) generation
Reproduction requires water
Bryophytes: mosses
Hepatophytes: liverworts
Anthocerotophyta: hornworts
Vascular plants
Seedless vascular plants
Dominant sporophyte (diploid) generation
Depend on water for reproduction
Examples
Club mosses
Whisk fern
Horsetails
Ferns
Seed-producing plants
Gymnosperms
Cycads
Ginkgo
Conifers: cone bearing trees
Angiosperms
Monocots
Contains one seed leaf
Produces only herbaceous tissue
Flower parts in multiples of three
Dicots
Contains two seed leaves
Produces woody tissue
Flower parts in multiples of four or five
The Plant Body
Root Structure
Tap root: main body of dicot roots. Example: carrot.
Fibrous root: all roots of similar diameter. Monocots, such as grasses.
Root cap protects tips of roots as they grow.
Root Function
Anchorage: Holding plant in the ground.
Tap roots travel deep into the ground.
Fibrous roots help prevent erosion of soil.
Absorption: Take up water and nutrients from the soil.
Conduction: Transport water upward from the ground in xylem. Transport food downward from the leaves in phloem.
Storage: Store food or water in the tissues. Example: carrot, sweet potato.
Stem Structure and Function
Contains vascular tissue to transport material to and from the leaves.
Epidermal cells may contain chloroplasts for photosynthesis.
May be underground or modified for food storage.
Leaf Structure
Upper epidermis and lower epidermis protect leaf.
Palisade layer contains chloroplasts.
Chloroplasts: specialized cell organelle that contains chlorophyll, a pigment used to trap light energy for photosynthesis.
Spongy layer contains chloroplasts and surrounds air spaces.
Stomata provide openings into the leaf space.
Vein made of a vascular bundle that transports materials to and from the leaf.
Cuticle covers upper surface.
Waxy, waterproof covering protecting surface plant tissue, such as leaves, stems, flowers, and roots.
Leaf Function
Photosynthesis.
May be modified for food storage or for reproduction.
Problems facing Plants
Obtaining water and mineral nutrients: roots in contact with moisture; symbiotic fungi
Transporting food and water within the plant: vascular tissues
Preventing evaporation: cuticle
Problems facing Plants
Obtaining gases for photosynthesis and respiration: stomata
Obtaining sunlight for photosynthesis: green leaves or stems
Supporting the plant body: xylem
Coordinating growth: hormones
Problems facing Plants
Getting gametes together
pollen
Dispersing new individuals
seeds


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