5. least specialized member of the system
compactly arranged
cells of various shapes
possess living protoplast
with cutin in cell walls as incrustation and
adcrustation
6.
7.
8.
9.
10. Sometimes the entire epidermis consists of
specialized cells
solid layer of sclereids
cells contain chloroplastids (Polypodiaceace)
11.
12.
13.
14. are apertures in the epidermis bounded by 2
guard cells
may be functionally associated with subsidiary
cells or accessory cells
15.
16.
17.
18.
19.
20.
21. basipetal- monocots
mosaic- dicots
both types occur in
vascular cryptogams
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34. Types according to function
a. Glandular
stalk and head (produces secretions)
b. non -glandular
Development
35.
36.
37.
38.
39. outermost layer with cuticle
inner layers
differentiated commonly as water-storage tissue
lacking chlorophyll
expand more than the outer (undergo more anticlinal
divisions)
Lithocysts keep pace with increasing depth of
the epidermis by expansion and intrusion into
the mesophyll
40.
41. cortex with chloroplastids
velamen is for absorption of water
composed of dead cells, the walls of which are
strengthened by band-like or reticulate
thickening. When the air is dry, these cells are
filled with air, but when the rain falls, they
become filled with water. The exodermis
situated at the inner edge of the velamen is
interrupted with passage cells through which
the absorbed water may be transferred.
42. Special structures termed pneumatodes are
present in the velamen. The function is to
enable gas exchange during periods when the
root is saturated with water. Some say that the
function is not water absorption because
exodermis and velamen are impermeable to
water and certain solutes. The principal role is
mechanical protection and prevention of excess
loss of water from the cortex
