Transcript Plants as Living Organisms

Plants as Living Organisms
Unit 3
Plant Kingdom
• Thousands of plant species
• 4 major groups of plants
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Mosses
Ferns
Gymnosperms – “naked seed”
Angiosperms
Gymnosperms
• Naked Seed
• Produce seeds that lay naked on the scales
of cones
• Examples:
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Pine
Spruce
Fir
Redwood
Angiosperms
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Seed enclosed in a vessel
Flowering Plants
All major crops are flowering plants
2 classes of flowering plants
– Monocots - Long, narrow blades w/ parallel veins
• Flower parts in multiples of 3
• Contain 1 cotyledon
– Dicots - Broad to narrow leaves w/ netted veins
• Flower parts in multiples of 4-5
• 2 Cotyledons
Plant Life Cycles
• The time from when a plant begins
growth until the time it dies
• Annuals
• Biennials
• Perennials
Annuals
• Compete life cycle w/in 1 year
• Many crops are annuals
Biennials
• Require 2 growing seasons to produce
• Germinate and grow leaves and roots
during 1st season
• Flower and produce fruit in 2nd season
Perennials
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Plants w/ more than 2 years in a life cycle
May produce seeds for many years
Dormant in winter months
Herbaceous – shoots die in frost, but
roots and crown stay alive
• Woody – shoots survive winter
• Hardy – plants that tolerate cold temps.
Plant Structures and Functions
• Roots
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Absorb H2O & minerals
Anchor plant
Store food
Majority in top 2 feet of soil
Root hairs: increase surface area
Primary root: single, main root
Secondary roots: branches off primary
Root cap: Protect root as it grows in soil
Roots (cont’)
• Tap root: Thick main root grows straight
down
– Tolerate dry periods – deep in soil
• Fibrous Root: numerous slender roots
– Located near soil surface – less tolerant
Stems
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Hold leaves in position
Conduct water & minerals & food
Store food & water
Produce new living stem tissues
Xylem: transport minerals and water
from roots to leaves
• Phloem: transport manufactured food
from leaves to plant
Stems (cont’)
• Buds: contain under-developed parts
• Bud scales: Cover and protect parts
• Terminal Bud: Large bud at top of plant
– Contains apical meristem – primary growing point
• Lateral Buds: found at attachment of leaves
– Apical dominance: prevent lateral buds from
developing
Leaves
• Responsible for food production
(Photosynthesis)
• Epidermis – protective layer of cells
• Cuticle – protects against water loss
• Stomata – exchange of Oxygen, Carbon
Dioxide and Water
• Transpiration: movement of water vapor
through stomata
Types of Leaves
• Broadleaf plants – wide, flat leaves
– Leaf Blade: large part of leaf, provides
surface area for solar NRG
– Petiole: Leaf stalk
– Simple Leaves: Single leaf blade and petiole
– Compound leaves: 1 petiole and 2+ blades
(leaflets)
Types of Leaves
• Narrowleaf plants: needle shape leaves
• Deciduous: Woody perennial loses leaves
in fall
• Evergreen: Keep leaves
Flowers
• Reproductive organs
• Produce seeds
• Complete Flower: 4 parts
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Sepals: Protect flower b4 opening
Petals: appear leaf like are often colorful
Stamens: Male reproductive parts
Filament: stalk
Anther: produces & holds pollen
Complete Flowers
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Pistil: Female reprod. Part
Stigma: Sticky surface to catch pollen
Style: Neck of pistil
Ovary: Contains ovules to produce eggs
and develop seeds
• Incomplete Flower: missing 1+ parts