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 • ______Ø photosynthesis Ø storage Ø support • ______Ø conduction Ø support • ______Ø Covering Ground Tissue System

• ______Tissue • Collenchyma Tissue • Sclerenchyma Tissue Parenchyma Tissue

• Made up of Parenchyma Cells • ______Cells • Primary Walls • Functions – photosynthesis – storage Collenchyma Tissue

• Made up of Collenchyma Cells • Living Cells • Primary Walls are thickened • Function – _Support_____ Sclerenchyma Tissue • Made up of Sclerenchyma Cells • Usually Dead • Primary Walls and secondary walls that are thickened (lignin) • ______or ______• Function – Support Vascular Tissue System

• Xylem – H2O – ______– Vessel Elements • Phloem - Food – Sieve-tube Members – ______Xylem • Tracheids – dead at maturity – pits - water moves through pits from cell to cell • Vessel Elements – dead at maturity – perforations - water moves directly from cell to cell Phloem

Sieve-tube member • ______– alive at maturity – lack nucleus – Sieve plates - on end to transport food • ______– alive at maturity – helps control Companion Cell (on sieve-tube the side) member cell Dermal Tissue System • Epidermis – 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 • ______– Tap Root – Lateral Roots • ______– Stems • Nodes (leaves are attached) • Internodes – Leaves • blades • petioles – Buds • Terminal (apical) Plant • Axillary Systems Plant Growth

• ______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 Lateral Meristems • increases girth called secondary growth – ______- produces secondary xylem and secondary phloem – ______- produces cork (outer most layer of bark) Pine Tree w/ 8 Cotyledons! The Root System • Functions – anchor plant – absorb minerals, water and nutrients – store food • Systems – ______- one large root with smaller lateral roots (dicots) – ______- threadlike roots (monocots) 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 Tissue • 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)

Dicot Root vs. Monocot Modified Roots

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

Sclerenchyma cells

Phloem Xylem Dicot Stem Vs. Monocot (35.16)

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) • Pith • Secondary Phloem • Primary Xylem • Primary Phloem • Secondary Xylem • Cortex (wood) • Phelloderm • Vascular • Cork Cambium

Cambium Periderm • Cork (outer layer of bark) 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.

Secondary Growth of a Stem Modified Stems • ______- 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 Leaf Structure Leaves • Epidermis – ______- openings on underside of leaf – Guard Cells - surround stomata – Cuticle - waxy coating excreted by epidermis • Mesophyll - middle of leaf – ______- photosynthesis – Spongy layer - gas exchange Modified Leaves • ______- attachment • Bracts –modified leaves that surround a group of flowers • Spines - protection • Storage Leaves - succulents