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B.
Anatomy[Lab]35.12
(internal
structure based on lineage, position and
function)
Anatomy,
on the other hand, is concerned with the
lineageof cells (i.e.
who their parents were) and
their positioninside
the plant, in addition to their function.
We will investigate the
anatomy of the plant much more thoroughly in lab. Here is a
brief overview.
An
anatomist, would subdivide our plant into:
1.
Dermal tissue(mediates
contact with environment) Dermal
tissueor the epidermis is
a single layer of tightly packedcells on the
outside that covers and
protects the plant.
The
epidermismediates
contact between the plant and its
environment.
a.
root epidermis[!]
root hairs
The epidermis of the root
produces cytoplasmic extensions
calledroot hairs
that absorb water and
minerals.
b.
leaf epidermis[!]cuticle
The epidermis of the leaf
secretes a waxy
cuticleto prevent water
loss.
c.
trichomes (epidermal hairs) - defense Some
epidermal cells have been modified to form
trichomesor epidermal
hairs that help to defend the
plant against being eaten.
d.
guard cells - control stomata
Guard
cellsare also
modified epidermal cells. They control the
opening and closing of
stomata, holes in the surface of the leaf that
allow gas
exchange.
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