Plant Structures Roots, Stems, and Leaves Chapter 23

Plants Seed plants have three main structures: Seed plants have three main structures: Roots Stems Leaves Linked together by various means Linked together by various means

Function of Roots Roots Roots Absorb/Transport water and nutrients Absorb/Transport water and nutrients Anchor plant to the ground Anchor plant to the ground Hold soil in place and prevent erosion Hold soil in place and prevent erosion Storage of sugars made Storage of sugars made In photosynthesis

Functions of Stems Stems Stems Support for the plant body Carries nutrients throughout plant

Functions of Leaves Leaves Leaves Main photosynthetic systems Main photosynthetic systems Sight of gas exchange Sight of gas exchange

Tissues in Plants 1. Dermal tissue 2. Vascular tissue 3. Ground tissue

Tissues in Plants 1. Dermal Tissue Outer covering Cuticle – waxy coating Roots have dermal tissue Root hairs Stomata and Guard cells within

Tissues in Plants 2. Vascular Tissue 2. Vascular Tissue Transport System Carries water and Carries water andnutrients. Xylem Xylem (Water in) (Water in) Phloem Phloem (Glucose out) (Glucose out) V for vascular, V for vein!

Tissues in Plants 3. Ground Tissue 3. Ground Tissue Cells between dermal and vascular tissue

Roots Types of Roots Types of Roots Taproots Taproots Long, thick root Long, thick root Reach deep into the soil to obtain water/nutrients Reach deep into the soil to obtain water/nutrients Fibrous roots Fibrous roots Many thin roots Many thin roots Spread out away from plants to find water and nutrients quickly Spread out away from plants to find water and nutrients quickly Helps to reduce erosion of soil Helps to reduce erosion of soil TaprootFibrous root

Roots Root Functions Root Functions Anchor plant Anchor plant Absorb water/nutrients Absorb water/nutrients Storage of sugar Storage of sugar

Stems Functions Functions Produce leaves, branches, and flowers Hold leaves up Transport substance between roots and leaves

Stems 2 types of stems 2 types of stems 1. Herbaceous 2. Woody

Stems Xylem and phloem Transport water and nutrients Xylem and phloem Transport water and nutrients Contain nodes Contain nodes – attachment for leaves – attachment for leaves

Leaves Function Function Main site of: Main site of: Photosynthesis Photosynthesis Covered by: Covered by: epidermis and cuticle epidermis and cuticle Create water proof barrier Create water proof barrier

Leaves Mesophyll (meso=middle) 1. Palisade mesophyll -site of most photosynthesis 2. Spongy mesophyll -some photosynthesis

Leaves Stomata – pores in the underside of the leaf Gas exchange CO 2 in O 2 out Guard Cells – Surround the stomata Open and closes stomata ***Stomata closed at night to prevent H 2 O loss

Leaves Transpiration Transpiration Loss of water through its leaves Loss of water through its leaves Replaced by water drawn into the leaf Replaced by water drawn into the leaf

Transport in Leaves Vein (Vascular Tissue) Vein (Vascular Tissue) Xylem “Water in” for photosynthesis Phloem “Glucose out” after photosynthesis

Tropisms Growing toward or away from a stimulus Phototropism Stimulus = Light Leaves have positive phototropism Thigmotropism Stimulus = Touch Vines have positive thigmotropism

Tropisms Growing toward or away from a stimulus Gravitropism Stimulus = Gravity Roots have positive gravitropism Hydrotropism Stimulus = Water Roots have positive hydrotropism

Plant Adaptations

Types of Adaptations Structural adaptations are the way something is built or made. Structural adaptations are the way something is built or made. Behavioral adaptations are the way something acts naturally or by instinct. Behavioral adaptations are the way something acts naturally or by instinct.

Behavioral Adaptations Adaptations to get food Adaptations to get food Plants like the Venus fly trap, trap insects for food. Plants like the Venus fly trap, trap insects for food.

Behavioral Adaptations Adaptations for reproduction Adaptations for reproduction Plants drop seeds to grow new offspring. Plants drop seeds to grow new offspring.

Structural Adaptations Adaptations to get water and nutrients Adaptations to get water and nutrients Roots soak up water and nutrients from soil. Roots soak up water and nutrients from soil.

Structural Adaptations Adaptations for defense Adaptations for defense Spines and thorns protect plants from predators Spines and thorns protect plants from predators

Structural Adaptations Adaptations for defense Adaptations for defense Poison Ivy and Poison oak have toxins that give predators a painful itchy rash. Poison Ivy and Poison oak have toxins that give predators a painful itchy rash.

Desert Adaptations Small leaves or spines on desert plants conserve water. Small leaves or spines on desert plants conserve water. Thick waxy skin holds in water. Thick waxy skin holds in water. Roots near the soils surface soak up rain water quickly before it evaporates. Roots near the soils surface soak up rain water quickly before it evaporates.

Rainforest Adaptations Smooth, slippery bark keeps vines from killing trees. Smooth, slippery bark keeps vines from killing trees. Slide shaped leaves lets rain run off so fungus doesn’t grow on plants. Slide shaped leaves lets rain run off so fungus doesn’t grow on plants.