Plant Structure And Growth

The Plant Body is Composed of Cells and Tissues Tissue systems (Like Organs) made up of tissues Made up of cells

Plant Tissue Systems ____________________ ___________________ photosynthesis storage support conduction ___________________ Covering Ground Tissue System Vascular Tissue System Kind of like Organs in an animal Dermal Tissue System

Ground Tissue System Parenchyma ___________ Tissue Collenchyma Tissue Sclerenchyma Tissue

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

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

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

Vascular Tissue System Xylem – H2O ___________ Vessel Elements Phloem - Food Sieve-tube Members __________ Tracheids Companion Cells

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

Phloem Sieve-tube members Companion Cells _____________ alive at maturity lack nucleus Sieve plates - on end to transport food helps control sieve-tube member cell Sieve-tube member Companion Cells Companion Cell (on the side)

Dermal Tissue System Epidermis ___________ – Periderm Single layer, tightly packed cells Complex Tissue – Does different things in different areas (roots vs. leaves) usually transparent secretes cuticle ___________ – replaces epidermis in woody plants protection Periderm

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

Plant Growth Meristematic ______________ Tissue generates cells for new growth (like stem cells in animals) apical meristems lateral meristems

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

Lateral Meristems increases girth called secondary growth __________________- produces secondary xylem and secondary phloem ______________- produces cork (outer most layer of bark) Vascular Cambium Cork Cambium

Pine Tree w/ 8 Cotyledons!

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

Root Structure Four Regions _________– protection, also secrete polysaccharide slime to lubricate Region of ___________- new cells Region of __________ - cells get longer Region of _________ - cells begin to specialize Root Cap Cell Division Elongation Maturation

Root Tissue Stele Protoderm - gives rise to the epidermis Ground Meristem Cortex (external to vascular tissue) Procambium - gives rise to the _______ (the vascular tissue of a root or stem) xylem and phloem may include pith (parenchyma cells surrounded by vascular tissue) Stele

Dicot Root vs. Monocot Xylem (larger, in red) Endodermis Phloem (smaller, greenish) Pericycle – one layer IN from endoderm, gives rise to lateral roots “Pith” – central core of parenchyma cells surrounded by xylem and phloem

Modified Roots Food Storage Pnematophores Aerial Roots Water Storage carrots, sweet potatoes, yams Water Storage pumpkin family Propagative Roots cherries, pears Pnematophores mangroves Aerial Roots orchids Buttress Roots tropical trees Haustoria dodder

Shoot System

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

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

____________– stele (vascular tissue) divided into strands in stems and leaves Vascular Bundle Sclerenchyma cells Phloem Xylem

Dicot Stem Vs. Monocot (35.16) Vascular Bundle Ground Tissue (Pith) (Cortex) How can you tell root from stem?

Stems (Secondary Growth) Occurs to increase girth (thickness) Vascular Cambium produces secondary xylem and secondary phloem Cork Cambium produces cork and phelloderm (thin layer of parenchyma cells) together these structures are called periderm (Cork Cambium, cork, phelloderm)

Secondary Growth Derivative Vascular cambium

Secondary Growth of a Stem

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

Older, inner layers of 2° Xylem – no longer transport water Younger, outer layers of 2° Xylem still function in transport All tissue outside vascular cambium Missing cortex and phelloderm!

___________ (Early) growth occurs more quickly. Cells are large and thin walled and have less strength. Summerwood (Late) growth occurs more slowly. Cells are thicker, more dense, and stronger. Springwood

Secondary Growth of a Stem

Modified Stems Stolons Cladophylls __________ - horizontal stems above the ground (strawberries) Rhizomes - horizontal stems below the ground (Irises) Tubers - swollen areas of rhizomes or stolons (Potatoes) Bulbs & Corms - vertical shoots under ground (onions, garlic w/ mod storage leaves) _____________ - cactus pads Cladophylls

Leaf Structure

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

Modified Leaves Tendrils ___________- attachment Bracts –modified leaves that surround a group of flowers Spines - protection Storage Leaves - succulents