Plant Structure and Function

Plant Cells The Ground Tissues: Parenchyma cells Most flexible, thin walled cells For storage, photosynthesis, gas exchange and protection Spherical in shape Found in leaves, green stems.

Collenchyma cells Elongated strands or cylinders Support surrounding cells and tissue repair and replacement Stringy strands in celery Flexible and can stretch and bend without breaking

Sclerenchyma cells Lack cytoplasm and other living components when mature Provide support, are the thickest cells Involved in transport of materials These are the cells that make up “wood”

Plant tissues Meristematic tissue: Regions of rapidly dividing cells Apical meristems: tips of roots and stems Result in increase of length. Primary growth Intercalary: found in one or more locations along the stem So when you cut your grass it can grow from the tip again Lateral: Increases root and stem diameters. vascular cambium produces new transport cells cork cambium tough cell walls to protect, the outer bark

Dermal tissue: Epidermis: outer layer forming waxy cuticle Stomata – gas exchange Trichomes – gives leaves a fuzzy appearance, protect plant, can release a toxic substance and can help cool. Root hairs- increase surface area for absorption.

Vascular tissues: Xylem: water conducting cells, contains Vessel elements: tubular cells stacked end to end. Tracheids: long cylinders with pitted ends. Phloem: The main food-carrying tissue. sieve tube members and companion cells

Roots and Stems Roots: Root cap: Protection Epidermis, cortex (transport and storage), and pericycle. Types of roots taproot Fibrous root Modified root

Stems Main function is to support plant leaves and reproductive structures as well as transport of water and dissolved substances. growth comes from the apical meristem. Xylem and phloem growth causes the annual growth rings. Types of stems Tuber Rhizome Runner Bulb Corm