Plant Structure and Growth AP Biology Crosby High School

3 Basic Organs Root System Shoot System Monocot vs. Dicot Root Hairs Axillary bud Terminal bud Stolon, rhizomes, tubers, bulbs Leaves (Blade and Stalk)

3 Tissue Systems Dermal: Epidermis Vascular Ground Xylem Phloem Pith Tracheids Vessel elements Phloem Sieve-tube members Ground Pith cortex

3 Cell Types Parenchyma Collenchyma Sclerenchyma Sieve-tube members Synthesize and store organic compounds Collenchyma Support young and growing parts of shoot Sclerenchyma Tracheids and Vessel Elements Fibers and Sclereids

Plant Growth Indeterminate Growth Life cycles Annual Biennial Perennial Meristems produce initials and derivatives Apical Meristem Lateral Meristem

Primary Growth of Root Root Cap Zone of Cell Division Apical Meristem Quiescent Center Zone of Elongation Zone of Maturation

Primary Tissue Root Stem Protoderm Procambium Ground Meristem Vascular Bundles Dicots: arranged in ring w/ Xylem facing pith and Phloem facing cortex Monocots: More complex arrangement

Secondary Growth of Stem Vascular Cambium Interior secondary xylem and exterior secondary phloem Ray Initials Fusiform Initials Layers of Xylem growth produce wood

Secondary Growth of Stem Cork Cambium Bark: Phloem and Periderm Secondary Phloem does not accumulate Heartwood Sapwood

Mechanisms of Growth and Development Plane and symmetry of division Asymmetrical cell division Preprophase band Orientation of cell expansion Uptake of water is 90% of expansion Expansion is perpendicular to the plane

Mechanisms of Growth and Development Morphogenesis Positional information First plant cell division usually asymmetrical Homeotic genes Cellular Differentiation Reflects synthesis of different proteins Relies largely on gene expression

Phase Changes Meristem changes from one developmental phase to another Floral Meristem Identity genes Organ Identity genes Code for transcription factors Position determines which genes are expressed

Orientation of Expansion

Plane and Symmetry

Secondary Growth of Stem

Primary Tissue

Types of Growth

Modified Shoots

Cell Types

Plant Organs

Monocot vs. Dicot