Plant Structure And Growth The Plant Body is

Plant Structure And Growth

The Plant Body is Composed of Cells and Tissues l Tissue systems l made up of tissues l made up of cells

Plant Tissue Systems l Ground Tissue System photosynthesis Ô storage Ô support Ô l Vascular Tissue System conduction Ô support Ô l Dermal Tissue System Ô Covering

Ground Tissue System l l l Parenchyma Tissue Collenchyma Tissue Sclerenchyma Tissue

Parenchyma Tissue l l Made up of Parenchyma Cells Living Cells Primary Walls Functions l l photosynthesis storage

Collenchyma Tissue l l Made up of Collenchyma Cells Living Cells Primary Walls are thickened Function l Support

Sclerenchyma Tissue l l l Made up of Sclerenchyma Cells Usually Dead Primary Walls and secondary walls that are thickened (lignin) Fibers or Sclerids Function l Support

Vascular Tissue System l Xylem l l l Tracheids Vessel Elements Phloem l l Sieve-tube Members Companion Cells

Xylem l Tracheids l l l dead at maturity pits - water moves through pits from cell to cell Vessel Elements l l dead at maturity perforations water moves directly from cell to cell

Phloem l Sieve-tube Members l l alive at maturity lack nucleus Sieve plates - on end to transport food Companion Cells l l alive at maturity helps control sievetube member cell

Dermal Tissue System l Epidermis l l complex tissue usually transparent secretes cuticle Periderm l l replaces epidermis in woody plants protection

l Root System l l l Tap Root Lateral Roots Shoot System l Stems l l l Leaves l l l blades petioles Buds l l Plant Systems Nodes Internodes Terminal (apical) Axillary

Plant Growth l Meristematic Tissue l generates cells for new growth l apical meristems l lateral meristems

Apical Meristems l increases length called primary growth Protoderm - gives rise to dermal tissue l Ground Meristem - gives rise to ground tissue l Procambium - gives rise to vascular tissue l

Lateral Meristems l increases girth called secondary growth Vascular Cambium - produces secondary xylem and phloem l Cork Cambium - produces cork l

The Root System l Functions l l anchor plant absorb minerals, water and nutrients store food Systems l l taproots - one large root with smaller lateral roots (dicots) fibrous roots - threadlike roots (monocots)

Root Structure l Four Regions l Root Cap - protection l Region of Cell Division - new cells l Region of Elongation - cells get longer l Region of Maturation - cells begin to specialize

Root Tissue l l Protoderm - gives rise to the epidermis Procambium - gives rise to the stele l may include pith Ground Meristem l Cortex l l xylem and phloem

Monocot vs. Dicot Root

Monocot Root (inside to outside) l l Pith Xylem l l transport water transport food Pericycle l Endodermis l Phloem l l l dividing cells l l Cortex l l Casparian Strip made of suberin to regulate water and minerals Passage Cells to allow water to pass through storage Epidermis l protection

Dicot Root (inside to outside) l Xylem l l transport water Endodermis l Phloem l l l Pericycle l l transport food dividing cells l Cortex l l Casparian Strip made of suberin to regulate water and minerals Passage Cells to allow water to pass through storage Epidermis l protection

Modified Roots l Food Storage l carrots, sweet potatoes, yams

Modified Roots l Water Storage l manroot, pumpkin family

Modified Roots l Propagative Roots which produce adventious buds l cherries, pears

Modified Roots l l Pnematophores Prop Roots l mangroves

Modified Roots l Aerial Roots l orchids, ivies

Modified Roots l Buttress Roots l tropical trees

Modified Roots l Haustoria l dodder

Shoot System

The Shoot System l Made up of Stems, Leaves, Flowers, Fruits l l Stems - support, conduction, growth Leaves - photosynthesis Flowers - pollination Fruits - seed protection, dispersal

Stems (Primary Growth) l l Protoderm - gives rise to the epidermis Procambium - gives rise to the stele l xylem and phloem in vascular bundles dicots - found in ring l monocots - scattered throughout l includes pith in dicots Ground Meristem l Cortex l l

Vascular Bundle

Monocot vs. Dicot Stem

Monocot Stem (Inside to Outside) l l Ground Tissue Vascular Bundles l l l Xylem Phloem Fibers Cortex Epidermis

Dicot Stem (Inside to Outside) l l Pith Vascular Bundles l l l Xylem Phloem Fibers Cortex Epidermis

Stems (Secondary Growth) l Occurs to increase girth (thickness) l Vascular Cambium l l produces secondary xylem and phloem Cork Cambium l l produces cork and phelloderm together these structures are called periderm

Secondary Growth

Secondary Growth of a Stem

Secondary Growth of a Stem (Inside to Outside) l l Pith Primary Xylem Secondary Xylem (wood) Vascular Cambium l l l Secondary Phloem Primary Phloem Cortex Phelloderm Cork Cambium Cork

Modified Stems l Stolons - horizontal stems above the ground

Modified Stems l Rhizomes - horizontal stems below the ground

Modified Stems l Tubers - swollen areas of rhizomes

Modified Stems l Bulbs & Corms vertical shoots under the ground

Modified Stems l Cladophylls - cactus pads

Leaf Structure l l l Simple leaf Compound leaf Double Compound leaf

Leaf Structure

Leaves l Epidermis l l Stomata - openings on underside of leaf Guard Cells - surround stomata Cuticle - waxy coating excreted by epidermis Mesophyll - middle of leaf l l Palisade layer - photosynthesis Spongy layer - gas exchange

Modified Leaves l Needles - reduce water loss

Modified Leaves l Tendrils - long thin leaves for clinging

Modified Leaves l Spines - protection

Modified Leaves l Succulents – water storage