Plant Structure Plants have 4 major structures flower

Plant Structure

Plants have 4 major structures: flower stem leaf roots

Roots

Functions • anchors plant

Functions • absorbs and transports water and minerals

Most absorption takes place at the root tips which are covered with root hairs Mycorrhizae

Root Types Tap Roots Fibrous Roots

Tap Root - one main root - grows straight down to find deep water - Example: dandelions

Some store food

Tap Roots

Fibrous root - several roots from the base of the plant’s stem - get water close to the surface - Example: grass

Fibrous Roots

Roots

STEMS

Functions • Support leaves and flowers

Functions • Transport water, minerals, food

Functions • stores water and minerals as sugar or starch

Stem types • Herbaceous stems - soft, thin, flexible - usually green

Stem Types • Trees and Shrubs - hard and rigid - self supporting

Stem Types • Vines - slender, woody - need support

Herbaceous, Tree & Shrub, Vine?

Herbaceous, Tree & Shrub, Vine?

Herbaceous, Tree & Shrub, Vine?

Herbaceous, Tree & Shrub, Vine?

Nodes • Place where leaves attach to the stem

Node Arrangements – provides leaves with most sunlight

Alternate • One leaf per node

Opposite • Two leaves per node

Whorled • Three or more leaves per node

Alternate, Opposite, Whorled?

Alternate, Opposite, Whorled?

Alternate, Opposite, Whorled?

LEAVES

Function • Absorb sunlight to make food

Function • Bring in CO₂ and release O₂ (breathing)

Parts of a Leaf

Blade • Flat, broad section; contains cells for photosynthesis

Veins • Tube-like structures that carry nutrients

Petiole • Stalk that connects leaf to the stem

A deeper look…

• Epidermis – thin layer of cells that protect the leaf • Cuticle – waxy coating to reduce water loss

• Stomata – small openings in leaves for gas exchange • Guard cells – open and close stomata

Parts of a leaf

Parts of a leaf

Adaptations • leaves of cactuses are modified as spines

Adaptations • leaves of carnivorous plants catch and digest insects