Plant Structures

Importance of plants Food and shelter for many organisms Supply O2 for cellular respiration

Characteristics of Plants Eukaryotic Multicellular Autotrophs Cell walls made of cellulose

Leaves Broad, flat organ that traps light energy Cells contain 1000s of chloroplasts (photosynthesis) Location for most photosynthesis in plants

Stomata Openings in the cuticle of the leaf Regulated by guard cells - allow for gas exchange (CO2 in, O2 out) Can close to prevent water loss – transpiration

Cuticle Protective waxy layer on leaves Prevents evaporation & tissues from drying out

Adaptations of Leaves The leaf of the pitcher plant is modified to attract & then digest insects & other small prey due to lack of nitrogen. Plants that grow on forest floors produces broad leaves to capture the small amount of sunlight that penetrates between taller trees

Adaptations of the Leaves The narrow leaves of a pine tree contain a waxy epidermis as well as stomata shrunken below the surface of leaf to reduce water loss. Cactus and other succulents have a tick waxy coating and reduced leaves to prevent water loss in arid climates.

Roots Plant organ that: Anchors plant in ground Absorbs water & minerals from soil (assisted by root hairs) Transports nutrients to stem

Adaptations of Roots Exposed to air, ex. Epiphytes Usually for plants that need to grow on top of other plants to reach sunlight. Must get water from rain or mist because they are not in the soil. • Ex. Orchid Swollen portions that can have buds to produce new shoots. Ex. Tubers, radish, potato, rutabaga

Stem Provides structural support for upright growth Contains vascular tissues for transporting food, water, and nutrients from one part of the plant to another

Xylem: Water moves from the roots to the leaves through tubes

The sugars/food produced in the leaves move to the roots through the phloem tissue.

Summary Substance Direction Vascular Tissue Water Leaves  Roots Xylem Food/Sugar  Phloem

Adaptations of the Stem A tuber is a stem, usually growing underground, that stores food. Ex. potato A rhizome is a horizontal, underground stem. New shoots can form allowing the plant to undergo periods of dormancy. Ex. ginger

central stem surrounded by short, thick leaves. that protect the bulb A bulb is made up of a central stem surrounded by short, thick leaves. that protect the bulb & store food. Ex. Onion, garlic

Flowers- structures for reproduction w/out water