Plant Anatomy

Plant Cells

Parenchyma

  • provides basis for plant, function includes photosynthesis, gas exchange, storage and protection, are tightly packed.
  • In leaves and green stems with many choloroplasts.
  • Others in roots and fruits lack chloroplasts but have vacuoles for storage.

Collenchyma:

  • long elongated cells providing support and are found when pulled from celery stalk. (can be unevenly thick)
  • As it grows, the thinner portions of its walls expand letting it become flexible

Sclerenchyma:

Plant Tissue

Meristematic:

Dermal:

Ground Tissue:
-:forms of plant's internal and external material.
Includes parenchyma, collenchyma and schlerenchyma.
Functions: photosynthesis, storage and support.

Vascular:

  • internal system running stem length through plant, connects roots and leaves.

Thick walls with lignin making the walls strong and tough.
Supports mature plants

Sclereids: short, hard covering, distributed randomly.

  • fibre cells: needle shaped, small interior spaces, when stacked together forms tough elastic tissue.

Outer covering = epideris forming a protective covering over non woody and young woody plants.
Older woodies form periderm replacing epidermis forming cork.

Specialized Epidermal Tissue

  • Guard cells surround a stomata, controlling its size.
  • When stomata is open, gas exchange occurs.

Specialized structures

  • Trichomes: tiny growths on epidermis suface making leaf surface cool reducing evaporation.
  • Root hair: extension increasing surface area for water and nutrient absorption.

Xylem

  • water conducting, consists of tracheids and vessel elements.
  • Once they mature, they die, leaving non living cells in place, so fluids can pass.

Phloem

  • food conducting, two tupes = sieve tube elements and companion cells
  • Sieve have no nucleus and have plated ends with holes.
  • Apical meristem lets plantsroots and stem grow.
  • Intercalary meristem is found at the steam and base of leaf blades.
  • Circumference, girth or root increase leads to two types of lateral meristems: vascular and cork cambium.
  • Vascular-necessary for secondary growth, cork-produce cells developing tough walls and protective layer.
  • where new cells are produced, have embryonic tissues, makes up of meristems (rapidly divinding cells).
  • When they mature, can transfrom into any specialized plant cell

Root Structure

Root Structure

Root Cap- protective covering on the tip of the root

  • Consists of parenchyma cells that help protect the growing tissues as the root extends.
  • cells of root cap produce slimy substance.
    • Together with outside layer of cells, reduces friction as the root grows through materials such as soil
  • Cortex- layer of cell in between epidermis and vascular tissues of the root. All materials that enter the roots must pass through the cortex to get to the vascular tissue
  • This layer is composed of ground tissue made of parenchyma cells that transport and store water, food and minerals

absorb water and dissolved minerals

Roots

  • Outer Root Layer- covered in a layer of **dermal tissue
  • Epidermal cells produce root hairs increasing surface area of root.
  • Absorbs water and dissolved minerals.
  • All materials entering must pass cortex to go to vascular tissue.

Roots

  • Inner Root Vascular System: Inside the endodermis are the vascular tissues, xylem and phloem.
  • Monocots- xylem cells typically form a ring around the central core of cells called the pith. Phloem cells surround the xylem cells.
  • Dicots- xylem cells often form an X or star shape, phloem cells are between the arms of the star

Stems

Types

  • Tuber- enlarged part of an underground stem. Buds extending from it will grow into new potato plants
  • Bulbs- shortened, compressed stems surrounded by fleshy leaves (onion)
  • Corms- composed entirely of stem tissue with some scaly leaves at its top. (Crocuses)
  • Stolons- Horizontal stems that grow above ground, along surface of soil( Strawberry plants)

Function

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Structure and Function - provide support for plant's leaves and reproductive structures