Secret Life of Plants Plant Anatomy

Terms Node – place where leaf petiole attaches Internode – stem between nodes Terminal bud – at the end of a branch Axillary bud – at the base of a leaf

Tap root – large central, vertical root Lateral root – branches off the taproot Fibrous roots – all roots about the same size, no central tap root

Root Diversity Prop Root – support tall, top heavy plants

Storage roots – store food and water

Pneumatophores – air roots, enable root system to obtain oxygen

Stem Diversity Bulbs – vertical, underground shoots consisting of enlarged bases of leaves that store food

Tuber Enlarged ends of rhizomes specialized for storing food Eyes – clusters of axillary buds

Rhizome Horizontal stem that grows below surface

Leaf Diversity Tendrils – modified leaves, used to cling to support Spines – leaves, but photosynthesis is carried out in green flesh Storage leaves – stores water Brachts – leaves that surround group of flowers, attracts pollinators Reproductive leaves – produce adventitious plantlets, fall off and take root in soil

Tissue Types Dermal Tissue – outer protective covering – Epidermis – nonwoody plants – Periderm – woody plants Ground Tissue – neither dermal nor vascular – Pith – internal to vascular tissue – Cortex – external to vascular tissue Vascular Tissue – long distance transport of materials between roots and shoots – Xylem – water and minerals upward – Phloem – sugars downward

Xylem – Tracheids & Vessels Water transporting system

Phloem – Sieve tubes Sugar transporting system

Plant Growth Primary Growth – Growth in length of roots or shoots – Growth at the apical meristem (tips of roots and shoots) Secondary Growth (will do later) – Growth in diameter of stem or root – Growth at the vascular cambium – Growth at the cork cambium

Root Structure

Tissues in Dicot Root Epidermis – no cuticle Cortex – parenchyma, food storage Endodermis – inner layer of cortex, sealed Pericycle – outer rim of vasc. bundle, lateral roots Phloem – sugar transport Cambium – area of potential new xylem & phloem growth Xylem – water & mineral transport

Lateral Root Growth

Dicot & Monocot Stem

Tissues in Dicot Stem Epidermis Cortex Vascular Bundles Phloem Cambium Xylem Pith ( more storage)

Tissues in Monocot Stem Epidermis Ground tissue Scattered vascular bundles in the ground tissue – Only phloem and xylem, no cambium

Leaf Anatomy

Tissues in mesophytic leaf Upper epidermis Palisade mesophyll Vein – Xylem – Phloem – Bundle sheath cells surround the X and P Spongy mesophyll with air spaces Lower epidermis

Epidermis details Cuticle (Wax) layer on outside of epidermis Ordinary Epidermal cells have no chloroplasts Stoma – opening in the leaf for gas exchange Guard cells (with chloroplasts) are on either side of the stoma Usually more stoma on the bottom of the leaf

Mesophyll Region Photosynthetic cells – Palisade cells maximize exposure to light – Spongy cells allow accumulation of gases Veins – Xylem delivers water and minerals – Phloem transports photosynthetic products for metabolic needs of cells or storage – Bundle sheath cells surround vein & protect

Secondary Growth Growth in Girth Vascular cambium produces secondary xylem and phloem Cork Cambium produces periderm and cork