Ground Tissue  Diverse functions such as aiding in photosynthesis, storage, and support.

ROOTS, STEMS & LEAVES

Roots  Take in water & minerals and transport them to the rest of the plant.  Also helps anchor the plant to the ground.

Root Structure  Root Cap: tip of root. Protects the root as it grows  Root hairs

2 Types of Roots  Taproot: thick root with few small branching roots. Helps anchor.  Fibrous: numerous roots about the same size. Helps with rapid water absorption.

Stems  Support for leaves and reproductive structures.  Categorized as Woody or herbaceous (non- woody)

Leaves – Main organ for Photosynthesis  Petiole: attaches leaf to stem  Epidermis: outer layer of cells. Structure:

Leaves – Main organ for Photosynthesis  Palisade mesophyll: contains many chloroplasts. Most photosynthesis happens here  Spongey mesophyll: loosely packed cells. Allows gases to move through. Structure:

Transpiration  water is carried from roots to leaves where it evaporates through the stomata.

Leaf Adaptations  Spines & thick cuticle: reduce water loss. Ex) cactus  Insect Traps: to get needed nutrients. Ex) pitcher plant & sundew plant

Leaf Adaptations

Hormones  Auxin: stimulates the lengthening of cells

Hormones Cont’d  Gibberellins: causes an increase in overall size of plants, fruits, and stems; speed up seed germination  Ethylene: gas that promotes fruit ripening

Responses  Nastic Response: movement not dependent on the direction of stimulus.  Ex) Venus fly trap always moves in the same way

Responses  Tropic Response: growth response to external stimulus.  Positive tropism - movement towards the stimulus.  Negative tropism – movement away from the stimulus

Phototropism  response to light.  Ex) Sunflowers

Gravitropism  response to gravity.  Ex) Roots & stems

Thigmotropism  growth in response to contact.  Ex) Vine Plants