Plant Tissues Flashcards
Where does cell division occur in plants
Meristematic tissue
Name 3 meristems that develop from the apical meristem
Photoderm- gives rise to dermal tissue
Ground meristem- ground tissue
Procambium- vascular tissue
What do lateral meristems do
Produce tissue that increase the girth of roots and side branches-secoundary growth
Name the 2 types of lateral meristems
Vascular cambium- produces secondary tissues that function in support and conduction
Cork cambium- in woody plants only, lies outside the vascular cambium and inside the inner bark, produces secondary tissues
What type of tissues are produced by meristems
Simple tissues = parenchyma, collenchyma,sclerenchyma
Complex tissues= xylem,phloem,epidermis,periderm
What are intercalary meristems
Add to stem length in grasses and related plants that don’t have vascular or cork cambium
Describe parenchyma tissue
Composed of parenchyma cells
Found in alll major parts of higher plants
Spherical at first, think pliable walls
As cells push up, wall flattened at points
Most have 14 sides and large vacuole
Name 3 specialised parenchyma cells
Aerenchyma cells -trapping air with extensive intercellular spaces, floats
Chlorenchyma- contain chloroplasts-pho
Transfer cells-develop irregular extensions of inner wall, increased s/a, transfers dissolved substances between adjacent plant cells
Describe collenchyma tissue
Flexible support for leaves and floral parts.
Alive, thicker cell wall, just beneath epidermis, longer than wide.
Describe sclerenchyma tissue
Thick,rough secondary walls,contains lignin.
Dead @maturity
Function in support.
Name 2 forms of sclerenchyma
Scleroids
Fibres
What are the three basic complex tissues present in plants
Dermal- covers putter surface. Epidermal and parenchyma tissue.
Ground- simple/complex, parenchyma, collenchyma and sclerenchyma
Vascular- transport food and water.
What are complex tissues composed off ?
Apical meristems and vascular cambium.
What does the xylem consist of?
Parenchyma cells Fibres Vessels Trachieds Ray cells.
What is the function of vessels
Allows liquid to continue to flow
Tracheids
Tapered at each end, each overlap with another tracheid.
Ind. cells dead at maturity.
No perforation plate- pits instead where two tracheids meet.
What are pits ?
Areas with no secondary cell walls which allows water to pass from cells to cells.
Boarded pits contain a cell membrane and a thickened region. This can help control the passage of water.
What is the function of rays
Lateral conduction and food storage in plants.
Parenchyma cells, produced in horizontal rows in vascular cambium by ray initials.
What is the composition of phloem
Sieve tube members Companion cells Fibres Parenchyma Ray cells
What is the function of companion cells
Work in conjunction with sieve tube members to conduct food throughout the plant.
Explain sieve tube protection
The lining contains callose, which stays in solution as long as the cell contents are under pressure. If the plant is injured the callose precipitates to the nearest sieve plate which forms a callose plug to prevent leaking and damage
What is the composition of dermal tissue
Pavement cells
Guard cells
Parenchyma
Function of ground tissues
Parenchyma- pho in leaves, storage in roots
Collenchyma- support in areas of active growth
Sclerenchyma- shoot support in areas where growth has ceased.
