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 (Functions) 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 Different types of Ground Tissue l l l Parenchyma Tissue Collenchyma Tissue Sclerenchyma Tissue l Helpful hint: remember which ones are living or dead at maturity and which have only a primary wall and which have a secondary wall)

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

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

Sclerenchyma Tissue l l Made up of Sclerenchyma Cells Usually Dead at maturity Primary Walls and Secondary Walls which are thickened with lignin There are two types l l l Fibers (seen in the top picture - red cells on top and bottom) Sclerids (seen in the bottom picture) Function l Support

Vascular Tissue System l Xylem (two types of cells) l l l Tracheids Vessel Elements Phloem (two types of cells) l l Sieve-tube Members Companion Cells

Xylem l Tracheids l l l Dead at maturity They have pits water moves through pits from cell to cell Vessel Elements l l Dead at maturity They have perforations water moves directly from cell to cell

Phloem l Sieve-tube Members l l alive at maturity lack nucleus at maturity 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 secondary phloem l Cork Cambium - produces cork and phelloderm 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 l You will need to be able to recognize the difference between a monocot root and a 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

Monocot Root l You will need to be able to recognize parts l l l l Epidermis Cortex Endodermis (red circle) Pericycle (one layer inside the red circle) Pith Xylem (red) Phloem (green)

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

Dicot Root l You will need to be able to recognize parts l l l l Epidermis Cortex Endodermis (red circle) Pericycle (one layer inside the red circle) Xylem (red) Phloem (green) No pith

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 Parts l Fibers l Phloem l Xylem

Monocot vs. Dicot Stem You will need to be able to recognize the difference between a monocot stem and a dicot stem

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

Monocot Stem l You will need to be able to recognize parts l Epidermis l Cortex (very small) l Ground Tissue l Vascular Bundle l l l Xylem (red) Phloem (green) Fiber (red)

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

Dicot Stem l You will need to be able to recognize parts l Epidermis l Cortex l Pith l Vascular Bundle l l l Xylem (red) Phloem (green) Fiber (red)

Roots vs Stems Roots have Endodermis / Stems Vascular Bundles Monocot l l l Roots – has pith Stems – No pith Vascular bundles in a ring Dicot l l l Roots – no pith Stem – pith Vascular bundles are scattered

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 l l C – Vascular Cambian D – Differentiated cell (will turn into another type of cell) X – Xylem P - Phloem l The vascular cambian goes through mitosis and creates a cell (D) which on the inside of the plant becomes a xylem cell. The next mitotic division produces another cell (D) which is on the outside and becomes a phloem cell

Secondary Growth of a Stem l You will need to know the parts

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

Secondary Growth l l l Periderm is cork cambium and cork Bark is everything outside the vascular cambium Wood (to a botanist) is secondary xylem l Sap wood – still moves water l Heart wood – no longer moves water, hardened now used for support

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 – one blade after axillary bud Compound leaf – multiple blades called leaflets Double Compound leaf – leaflets broken up into smaller leaflets

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