Lesson 12 bio101 (c)Dr. Evangelista

Lesson 12 bio101 (c)Dr. Evangelista

• 2.
  Secretory
structures
   ecretion
the
release
of
substances
that
have
a
 S – special
physiologic
function
(enzymes,
hormones)
   xcretion‐
separation
of
products
eliminated
 E from
metabolism
  Secretion
is
used
to
include
excretion
:
   role
of
many
of
these
substances
is
not
known
   they
may
be
found
in
the
same
container
   Secretion
may
remain
in
the
cell
producing
it
 as
droplets
,
be
walled
off
from
the
cytoplasm
 or
leave
the
cell

• 3.
  Types
of
secretory
structures
   xternal
secretory
structures
 E   A.
Trichome
and
glands
   B.

Nectaries
   C.
Osmophors
   D.

Hydathodes
   nternal
secretory
structures
 I   A.
Secretory
cells
   B.

Secretory
spaces
   C.
Laticifers

• 4.
  Types
of
secretory
structures
   xternal
secretory
structures
 E   A.
Trichome
and
glands
   B.

Nectaries
   C.
Osmophors
   D.

Hydathodes
   nternal
secretory
structures
 I   A.
Secretory
cells
   B.

Secretory
spaces
   C.
Laticifers

• 5.
  Trichomes
and
glands
   trichomes
simpler
than
glands
although
no
sharp
 distinction
exists
between
glandular
hairs
and
glands
   Trichomes
   Contains
anti‐herbivore
secretions

   Glands
   Salt
glands‐
mechanism
for
the
plant
to
get
rid
of
excess
salt
 absorbed
from
the
environment
   Function
of
plants
living
in
salt
marshes
and
salt
infiltrated
 soils
in
coastal
marine
areas
   Glands
of
insectivorous
plants‐secrete
digestive
juices

• 6.
  Glandular
hair
of

 Urtica
dioica
 (stinging
nettle)
 ‐Upon
contact
with
an
 animal,
the
tip
breaks
off
 releasing
the
toxic
substances
 in
the
cell
as
it
penetrates
the
 skin.
 ‐
Reported
to
contain
a
 histamine
and
an
 acetylcholine


• 7.
  Salt
gland
of
 Tamarix
aphylla
 Note 
 that 
 the 
 gland, 
 which
 consists 
 of 
 two 
 basal
 collecting 
 cells 
 and 
 four
 secretory 
 cells, 
 is 
 sunken 
 in
 the 
 epidermis. 
 
 Salt 
 is
 transferred 
 symplastically
 from
the
leaf
mesophyll
into
 collecting
cells
and
secretory
 cells 
 and 
 apoplastically
 through
the
wall
labyrinth
to
 the
exterior

• 9.
    tructure
of
secretory
cells
 S   Have
dense
protoplast
   Large
nucleus

   echanisms
for
release
 M   1.
May
release
secretion
in
between
wall
and
 cuticle

   A.
Eventually
cuticle
bursts
(may
regenerate
 cuticle
or
dry
up
after
excretion)

   B.
Or
not
at
all
but
individual
cells
are
severed
 after
release
of
secretion
   2.Special
mechanism
(tip
breaks
off
and
 contents
e.g.
histamine
escape
into
wound)
 


• 11.
  Glandular
 trichome

• 12.
  Glandular
hair
of

 Urtica
dioica
 (stinging
nettle)
 ‐Upon
contact
with
an
 animal,
the
tip
breaks
off
 releasing
the
toxic
substances
 in
the
cell
as
it
penetrates
the
 skin.
 ‐
Reported
to
contain
a
 histamine
and
an
 acetylcholine


• 13.
  Nectaries
  May
occur
on
flowers
(floral
nectaries)
or
 vegetative
parts
(extrafloral
nectaries)

   Secretory
tissue

   restricted
to
the
epidermal
layer
or
may
 include
subsurface
layers
   have
dense
cytoplasm
   may
be
papillate
   are
closely
packed

   
have
thin
walls

• 15.
  Nectaries
  Sugars
of
nectaries
derived
from
phloem

   Nectar
excreted
through

   cell
wall
and
ruptured
cuticle
   
or
through
stomates

(that
are
not
able
to
 close
and
open)

• 16.
  Osmophors
   scent
of
the
flowers
produced
by
essential
oils

   originates
from
epidermis
of
perianth
or
from
 osmophors
(special
glands)
   osmophors
found
in
Aristolochiaceae,
Araceae
etc.
   floral
parts
differentiated
as
osmophors
may
 assume
the
form
of
flaps,
brushes
or
cilia
   may
be
distinguished
by
using
neutral
red

• 17.
  Method
to
 locate
 osmophors

• 18.
  Secretory
 tissue



of
 osmophors
 Emission 
 of 
 volatile
 secretion 
 is 
 of 
 short
 duration
and 
 is
associated
 with 
 utilization 
 of 
 large
 a m o u n t s 
 o f 
 s to ra ge
 products

• 19.
  Hydathodes
   A
structure
that
discharge
water
from
the
interior
 of
the
leaf
to
the
surface
   water
contains
dissolved
salts,
sugars
and
other
 organic
substances
   Eliminates
water
through
the
terminal
tracheid
   in
contact
with
epithem
   may
have
no
epithem
and
water
moves
through
 ordinary
mesophyll

• 20.
  Guttation,
the
exudation
of
water
droplets
 Occurs
when
water
absorption
>
loss
of
water

• 21.
  hydathode

• 22.
  Internal
secretory
structures
   ecretory
cells
 S   Crystal‐
containing
cells
may
die
after
 deposition
of
the
crystal
or
may
be
separated
 from
living
part
of
the
protoplast
   ecretory
spaces S 
   In
the
form
of
spaces
or
cavities
formed
by
 schizogeny,
lysigeny
or
their
combination
   Epithelial
cells
of
resin
canals
   Lysigenous
space
 


• 23.
  Secretory
cells

• 24.
  Secretory
cells
 A.

Cells
containing
tannins

 B.


Oil
idioblast

• 25.
  Secretory
 spaces
 A‐D.
Schizogenous
 cavities
 E.

Lysigenous
 cavity

• 26.
  Internal
secretory
structures
   aticifers
 L   Derived
from
the
word
latex
meaning
juice
in
 Latin
   Because
of
the
milky
appearance
of
the
latex,
it
 is
sometimes
called
lactiferous
cells
or
vessels
 from
the
Latin
word
for
milk,
lac

• 27.
    aticifers
 L  According
to
origin:
   1.

Simple
laticifer
–
derived
from
a
single
cell
   2.

Compound
laticifer
–
derived
from
union
of
 cells
  According
to
structure:
   1.
Articulated
laticifer
‐
(laticiferous
vessel)
   compound
in
origin
consists
chains
of
cells
   end
walls
may
remain,
become
perforated
or
 are
completely
removed

• 28.
    aticifers
 L   According
to
structure:
   1.
Types:
   Articulated

nonanastomosing‐
compound
 tubes
not
connected
with
each
other
laterally
 (Ipomoea,
Convolvulus,
Achras
sapota,
Allium,
 Musa)
   Articulated
anastomosing
‐
cell
chains
 connected
with
each
other
laterally
(Hevea,
 Lactuca,
Carica
papaya,
Manihot)

• 29.
  Laticifers
in
Allium
 sativum

• 30.
  laticifers

• 31.
    aticifers
 L   According
to
structure:
   Nonarticulated
laticifer‐
(laticiferous
cell)

   simple
in
origin

   through
continued
growth
develops
into
a
 tube‐like
structure
   Types:
   Nonarticulated
unbranched
–
develop
more
or
 less
straight
tubes
(Vinca,
Urtica,
Cannabis)
   Nonarticulated
branched
–
each
cell
forms
 branch
repeatedly
forming
an
immense
 system
of
tubes
(Nerium,
Ficus,
Euphorbia)

 

• 32.
    aticifers
 L  Composition
and
physical
state
of
 latex
   Liquid
matrix
with
minute
organic
suspension
   Matrix
contain:
carbohydrates,
organic
acids,
 salts,
alkaloids,
sterols,
fats,
tannins,
and
 mucilages
   The
dispersed
particles:
terpenes

i.e.,
 essential
oils,
balsams,
resins,
camphors,
 carotenoids
and
rubber
   Latex
may
be
clear
or
milky
   Flow
of
latex
in
when
cut
open
is
a
pressure
 flow

• 33.
  Composition
 of
laticifers
 Latex
with

numerous
 vesicles
;
contain
 polyterpenes
and
other
 compounds

• 34.
    aticifers
 L  Cytology
   With
living
protoplast
retaining
nucleus
at
 functional
maturity
   Cytoplasm
along
the
periphery
surrounding
 the
vacuolar
sap
   In
nonarticulated
form
of
many
plants,
the
 nuclei
undergo
divisions
resulting
in
a
 multinucleate
coenocytic
condition

• 35.
    aticifers
 L   Cytology
   if
multinucleate
in
articulated
forms,
it
is
due
 to
fusion
of
protoplasts
   the
latex
particles
are
formed
in
the
cytoplasm
   the
tonoplast
breaksdown
in
mature
laticifers;
 the
latex
particles
escape
into
the
vacuolar
sap
 which
become
part
of
the
latex

• 36.
    aticifers
 L  Structure
of
the
wall
   nonlignified
and
plastic
  Development
   Nonarticulated
laticifers
  A.

Branched


 o  Arise
when
the
cotyledons
are
initiated
in
 the
form
of
relatively
few
primordia
 o  grow
concomitantly
with
the
plant
into
 branched
systems
permeating
the
whole
 plant
body

• 37.
  Nonarticulated
 laticifer
of
nerium
 oleander
 (development)

• 38.
    aticifers
 L   Development
   Nonarticulated
laticifers
   B.
Unbranched
–
primordia
seen
in
 developing
shoot
(Vinca,
Cannabis)
or
in
the
 shoot
and
root
and
new
primordia
arise
 repeatedly
beneath
the
apical
meristem
by
a
 combination
of
intrusive
growth
and
 symplastic
growth

• 39.
    aticifers
 L   Development
   Articulated
laticifers
   A.
anastomosing

 o  develops
into
extensive
tube‐like
structures,
 by
constant
addition
of
new
primordia
to
 the
existing
ones
 o  in
the
hypocotyls
and
the
cotyledons
of
the
 embryo
in
the
mature
seed
 o  end
walls
of
primordia
are
intact
but
during
 germination
break
down
and
the
cell
rows
 are
converted
into
vessels

• 40.
    aticifers
 L   Development
   Articulated
laticifers
   A.
anastomosing

 o  the
vessels
are
extended
by
differentiation
of
 further
meristematic
cells
into
laticiferous
 elements
in
acropetal
direction
 o  where
the
vessels
lie
side
by
side,
parts
of
the
 common
wall
become
resorbed;
if
they
are
 further
apart,
the
intervening
cells
may
become
 changed
into
laticiferous
cells
with
resorption
 of
common
walls;
some
of
the
anastomoses
 may
end
up
blindly
 o  in
the
secondary
phloem
may
develop
from
 derivatives
of
fusiform
initials

• 41.
    aticifers
 L   Development
   Articulated
laticifers
   B.
nonanastomosing

 o  the
development
of
nonanastomosing
kind
 is
similar
to
anastomosing
laticifers,
except
 that
no
lateral
connections
are
established
 among
the
various
tubes

• 42.
  Articulated
laticifer
development

• 43.
    aticifers
 L   
Arrangement
in
the
plant
   frequently
distributed
generally
through
the
 plant

   sometimes
are
restricted
to
certain
tissues
   most
commonly
the
phloem
   may
occur
also
in
the
xylem
(Caricaceae)
   cortex
(Musa)
   pericycle
   mesophyll

• 44.
  Arrangement
of
laticifers
in
the
 plant

• 45.
    aticifers
 L   
Possible
function
   Vital
sap
vessels
like
blood
vessels
of
animals
   Take
part
in
the
translocation
of
assimilates
   Take
part
in
the
storage
of
food
materials
   They
form
an
excretory
system
   Protection
as
the
latex
may
play
a
role
in:
   covering
wounds
   
as
defense
against
herbivores
and
 microorganisms