Chapter 4: Plant Tissues Flashcards
Tissues
groups of cells that perform a certain function
Meristematic Tissues
- Majority of dividing cells
- Perpetually juvenile (stem cells)
- totipotent or pluripotent like stem cells
- Small, soft, thin-walled
- high active metabolically
- made of peranchyma cells
Examples of totipotent or pluripotent
- Thornless blackberries formed by a mutation in the root
Apical Meristems
- Tissues that are formed near the tip of shoot or root
- Present in seed
- Produce primary growth of primary tissues
- Produces leaves and buds
- Protoderm, Procambium, and Ground meristem
Protocambian
Leaves islands of cells behind it in lines
Ground Meristem
center of the root or shoot
Lateral Meristems
- Growing out as secondary growth
- Two types
– Vascular Cambium
– Cork Cambium
Vascular Cambium
- Meristem tissues left behind
- Outer layer of stems and roots.
- Woody tissue of the pant
Cork Cambium
- Some cells start to mature but they go back to form the cork cambium
- Makes the bark
- Divides outwardly
- Gets shed off
Parenchyma
- Common throughout the plant
- Thin - walled, spherical
- Oftern loosely grouped
- Vacuoles may store things
- Can divide
- Aerenchyma - filled with air
- Chlorenchyma
- Transfer Cells - specialized cells with irregular inner walls that secretes
Collenchyma
- spherical or elongated living cells
- Primary cell walls thickened in corners
- tough but flexible
- provide suppport
Example: celery
Sclerenchyma
- Thick, lignificad secondary walls
- Elongated cells
- usually dead when mature
- Protection and support
- Sclereids and fibers
- Scattered around in other tissues
- Gritty substance in a pear
- Contain sclerids
Complex Tissues
- Xylem
- Phloem
- Epidermis
- Periderm
Xylem types
Dead at maturity
Trachids
— Simple pits
— Bordered pits - limits the amount of fluid that gets through
Vessel Elements - transports liquid , has spiral thickening
Fibers
Ray Cells
Phloem
Cells are alive, squishy inner bark
Moves glucose and hormones
Cell types:
- Sieve tube members - no nucleus, transport molecules
- Companion cells
- Fibers
- Rays
Epidermis
-Epidermal cells -outer layer on young plant, one cell think. Secrete a waxy compound
- Root hairs
- Velamen roots
- Hair & gland cells
- Guard cells
Periderm
It is produced by the cork cambium and forms the bark. The secrete Suberin to make them water proof. The suberin is aromatic
Lenticels help the bark breath.
- Secretory tissues - secrete nectars, oils, bark
