Vascular Roots

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Vascular Roots

• D.L. Mowery
• Douglass High School

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Plant Tissues

• Plant structures are composed of 3 main tissues
• Epidermis outer layer of cells which protect
  the plant from water loss and from fungi and
  bacteria.
• Vascular Tissues transport water, sugars and
  other materials through the plant.
• Ground Tissues tissues that the vascular tissue
  is embedded in. Usually storage cells

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Roots

• Roots have many functions
• Anchor the plant
• Bind soil stops erosion
• Absorb water and minerals
• Store food (usually as starch)

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Root Types
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Taproots

• Large and fleshy in appearance, grow deep into
  the ground to search for food, are able to store
  food, which is particularly necessary for
  perennial plants during periods of dormancy, are
  mostly found in plants with two seed-leaves
  (dicots)

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Fibrous Roots

• Lie close to the surface of the soil, collect
  precipitation before it sinks deep into the
  ground, can often be found growing side by side
  with taproots the two types of root combine
  efforts to maximize efficiency. are mostly found
  in plants with one seed-leaf (monocots)

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Adventitious Roots

• Develop to help the plant climb for example,
  ivies help develop modified underground stems,
  such as bulbs, are common in both dicots and
  monocots

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Aerial Roots

• Modified to absorb water from the air

Aerial roots of an Orchid
Orchids in bloom
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Root Hairs

• Actually epidermal cells adapted to absorb water

Root Hairs

• Water enters the cells by Osmosis
• Minerals enter by Active Transport

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Regions of the root tip

• Region of Maturation - Differentiate into types
• Root hairs form
• Region of Elongation - Several times length
• Vacuoles merge
• Region of Cell Division
• Most cell division occurs at the edge of the zone
• Root Cap - cells covering root tip
• Protects tissue
• Gravity perception

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The Root Tip
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The Function of Root Tissues

• Epidermis
• Outer layer - protects from drying, water loss,
  infection
• Cortex
• Ground tissue located inside the epidermis
• Endodermis
• Regulates materials entering the center of the
  root
• Stele
• Pericycle the outermost layer of cells of the
  stele
• Vascular Cylinder- xylem and phloem
• Xylem transports water
• Phloem transports sugar
• Pith tissue located in the center of the stem
• Meristem accounts for the increase in length of
  the roots and stems
• Apical Meristem constant state of growth

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Monocot root X-section
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Dicot root X-section
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The Casparian Stripregulates the movement of
water
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Stele
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The End.