Angiosperms Flowering plants Most diverse group of plants (~275,000 species) Divided into two taxonomic groups Monocots Dicots

Shoot System Vegetative – stem and leaves Floral – end in flowers Photosynthesis Floral – end in flowers Reproductive structures

Shoot Morphology Nodes – leaves attach to stems Internode – stem between nodes Terminal bud – shoot tip Axillary bud – base of node

Bulbs and Rhizomes

Runners and Tubers

Tendrils and Cladophylls

Leaf Morphology Monocots Dicots Parallel veins Multi-branched network Palmate or pinnate veins Blade Petiole

Roots System Anchor plant Absorb and conduct water and nutrients Store food

Types of Root Systems Fibrous Taproot Most monocots Small, close to surface Taproot Most dicots Long central root

Increased Surface Area Root hairs Extensions off of surface root cells Mycorrhizae Symbiotic association between roots and fungi

Specialized Roots Store food Adventitious roots Thickened taproot Example – carrot Adventitious roots Grow from stems Example – prop roots of corn

Basic Plant Cell Anatomy

Parenchyma and Collenchyma Cells

Collenchyma Cells Thick primary cell walls Most lack secondary cell walls Stacked cylinders Support young plants

Parenchyma Cells Thin and flexible primary cell wall Most lack secondary cell walls Large central vacuole Photosynthesis and storage of food

Sclerenchyma Cells Rigid secondary cells wall with lignin Protoplast die at maturity Fibers – long thin bundles Sclerids – short irregular shapes

Vascular Cells Xylem Phloem Water and minerals Direction – roots to shoots Phloem Water, sugar, hormones Both directions

Xylem Structure Tracheids Bundles of small diameter tubes Pits in end wall allows water and minerals to flow from cells to cell

Xylem Structure Vessel elements Large diameter End wall either absent or perforated Pits allow water and minerals to flow between vessel element and tracheid Vessel element die after development and add support to the plant

Phloem Structure Sieve-tube element Companion cells End wall is perforated forming sieve plate Lose most of their internal components – only has plasma membrane, few mitochondria and some endoplasmic reticulum Companion cells Support and nourish adjacent sieve-tube elements

Vascular system is a continuous network of tubes

Leaf Anatomy

Leaf Summary Stoma Spongy/palisade layer Epidermis Vascular bundle Controls transpiration (water loss through leaves) Spongy/palisade layer Exchange of gases Photosynthesis Epidermis Transparent Wax coating to prevent water loss Vascular bundle Brings water and mineral to leaf through xylem Sends sugars to roots through phloem

Stoma

Plant Tissues Dermal Ground Vascular Outside covering Epidermis Stems and leaves – waterproof wax coating Roots – root hairs – absorb water Periderm Bark Ground Photosynthesis, support, storage Vascular Transport Xylem – water and minerals Phloem – water, sugar, amino acids, hormones

Plant Growth Apical meristem Lateral meristem (cambia) End of roots and shoots Increases length – primary growth Lateral meristem (cambia) Cylinder of cells along roots, branches and stems Increases width – secondary growth

Root Growth

Terminal Bud Growth

Monocot Stem

Dicot Stem

Dicot Secondary Growth

Annual Growth Rings