Plant Structures Roots, Stems, and Leaves

What are plants? Photosynthetic,eukaryotic, multi-cellular organisms. Photosynthetic,eukaryotic, multi-cellular organisms. The plant structure can be classified into two major regions : The plant structure can be classified into two major regions : The shoot system (stem and leaves); located above ground The shoot system (stem and leaves); located above ground The roots (located underground) The roots (located underground)

Specialized Organs in Plants Specialized Organs in Plants Stems Stems Support for the plant body Carries nutrients throughout plant Defense system to protect against predators and infection Few millimeters to 100 meters

Two Main Types of Stems Herbaceous Stem Green, fairly bendable Green, fairly bendable Woody Stem Covered with bark Covered with bark

Specialized Organs in Plants Specialized Organs in Plants Leaves Leaves Main photosynthetic systems Main photosynthetic systems Susceptible to extreme drying Susceptible to extreme drying Sight of oxygen/carbon dioxide intake and release Sight of oxygen/carbon dioxide intake and release

Specialized Organs in Plants Roots Roots Absorbs water and nutrients Absorbs 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 Protect from soil bacteria Protect from soil bacteria Transport water and nutrients Transport water and nutrients Provide upright support Provide upright support

Specialized Tissues in Plants Plant tissue systems Plant tissue systems Exist within the root, stems, and leaves Exist within the root, stems, and leaves Dermal tissue Dermal tissue Vascular tissue Vascular tissue Ground tissue Ground tissue

Specialized Tissues in Plants Specialized Tissues in Plants Dermal Tissue Dermal Tissue Outer covering Single layer of cells acts as protection

Specialized Tissues in Plants Vascular Tissue Vascular Tissue Transport System Transport System Subsystems Subsystems Xylem Xylem Phloem Phloem Subsystems are used to carry fluids throughout plant Subsystems are used to carry fluids throughout plant

Vascular Tissue System Xylem -carries water from the roots to the rest of the plant. Phloem- carries sugar from the leaves to the rest of the plant

Kinds of Plants Kinds of Plants There are two kinds of plants; non-vascular plants which don’t have xylem and phloem and vascular plants which do have xylem and phloem. There are two kinds of plants; non-vascular plants which don’t have xylem and phloem and vascular plants which do have xylem and phloem.

Specialized Tissues in Plants Specialized Tissues in Plants Ground Tissue (cortex) Ground Tissue (cortex) Cells between dermal and vascular tissue Provides structure Sometimes involved in photosynthesis

Common Types of Plant Tissue Parenchyma Parenchyma Thin cell walls, large vacuoles Thin cell walls, large vacuoles Collenchyma Collenchyma Strong, flexible cell walls Strong, flexible cell walls Sclerenchyma Sclerenchyma Extremely thick, rigid cell walls Extremely thick, rigid cell walls

Stem Structure Composed of three tissue layers Composed of three tissue layers Dermal tissue-protection Dermal tissue-protection Vascular tissue-transport Vascular tissue-transport Ground tissue-sometimes performs photosynthesis Ground tissue-sometimes performs photosynthesis Contain nodes – attachment for leaves Contain nodes – attachment for leaves Internodes – regions between the nodes Internodes – regions between the nodes Buds – undeveloped tissue Buds – undeveloped tissue Petiole-the stalk of the leaf, which joins the leaf to the node of a stem. Petiole-the stalk of the leaf, which joins the leaf to the node of a stem.

Stem Types Stem Types Monocot – vascular bundles are scattered throughout Distinct epidermis Dicot – vascular tissue arranged in a cylinder Pith – parenchyma cells inside the ring

Roots Root Functions Root Functions Anchor plant Anchor plant Absorb water Absorb water Absorb nutrients Absorb nutrients

Root Structure Root Structure Root Structure can be divided into four layers Root Structure can be divided into four layers Epidermis-outside layer (protection) Epidermis-outside layer (protection) Cortex-typically stores food Cortex-typically stores food Endodermis-control movement of materials into vascular tissue Endodermis-control movement of materials into vascular tissue Central cylinder – vascular system Central cylinder – vascular system Key role in water/mineral transport Key role in water/mineral transport

Root Structure

Roots Types of Roots Types of Roots Taproots Taproots Found in dicots Found in dicots Long, thick root Long, thick root Hickory and oak trees Hickory and oak trees Fibrous roots Fibrous roots Found in monocots Found in monocots No single root larger than any other No single root larger than any other Many thin roots Many thin roots

Leaves Main sight of photosynthesis Main sight of photosynthesis Consist of: Consist of: Blade – thin flattened section Blade – thin flattened section Petiole – stalk that attaches stem to blade Petiole – stalk that attaches stem to blade Covered by epidermis and cuticle Covered by epidermis and cuticle Create water proof barrier Create water proof barrier

Structure Wide Helps to catch more light energy Thin Help get carbon dioxide from bottom to top of leaf for photosynthesis

Leaves Leaf Functions Leaf Functions Photosynthesis – occurs in the mesophyll Palisade mesophyll – absorb light Spongy mesophyll – beneath palisede level Stomata – pores in the underside of the leaf Guard Cells – Surround the stomata

Leaf structure Greener on top CO 2 gets in here What kingdoms are the above organism members of? What characteristics do they have in common? How are they different?

Organization of Living Organisms Living Organism Is composed of Organ Systems are composed of Organs Tissues Cells Vascular Plants Vascular Plants are composed of Organ Systems are composed of Organs Tissues Cells