2. Tissue
1. Meristematic 2. Permanent tissue
tissue
a. Simple b. Complex c. Secretory
1.parenchyma 1.xylem 1. External secretory
2.collenchyma 2.phloem structures
3.sclernchyma 2. Internal secretory
structure
3. Secretory Tissue
many substance are released from the cytoplasm
of the cells
Among these secretion some are beneficial to the
plant some are not
These substance are called secretions and the
cells/tissues concerned with these secretions are
called secretory tissues
The structure and chemical composition of
secretions varies
Secretion may be water, nectar, salt, tannins,
resins, latex, gums, digestive enzymes, hormones
etc.
5. Laticifers / laticiferous tissue
Specialized parenchyma cells; living
Fused tube like cells filled with viscous fluid called latex
White in color / yellow( Papaveraceae and
Cannabinaceae)/ colorless ( Moraceae)
Suspension contains various substances like waxes,
resins, proteins, essential oils, alkaloids and sugars
Alkaloid-Papaver
Enzymes-Papaya
Latex-source of rubber (Hevea and Ficus)
Chicle (Achras); Papain (Corica)
Monocots - Dracaena
6.
7. Cell structure of laticifers
Cells contain living protoplast
Vacuoles well developed
Vacuoles store latex
Cells usually multinucleate
Latex may be milky white , colored or
colorless
8.
9. Chemical composition of latex
Latex is a mixture of chemical compounds
Contains carbohydrates, organic acid, alkaloids, terpenes,
resins and enzymes
Latex of Euphorbia mili contains dumbbell shaped starch
grains
Latex of Papaverm somniferum contain alkaloids (morphine,
codeine)
Latex of Carica papaya contain digestive enzyme popain
Latex of Hevea contain rubber
Latex of Achras saporta contain chicles
Rubber particles suspended in the latex
10.
11. Types of laticifers
On the basis of structure and
development-
Nonarticulate latex ducts / Latex cells
Articulate latex duct/ Latex vessels
- Content and funtion of them are same
and both may occur in same family
13. Nonarticulate latex ducts/ Latex
cells
These are multinucleated cells of immeasurable length
Initials originates within the meristematic mass of embryo
Develops from single cell
This initials grow more rapidly than neighbouring cells and
form highly branched systems in the intercellular space
Elongate by intrusive growth
Occupy intercellular spaces of other cells
Eg. Apocynaceae
Asclepiadaceae
Euphorbiaceae
Urticaceae
14. Nonarticulate latex ducts
They originate as minute structures, elongate quickly and
ramify in all directions of the plant by repeated branching
,but they not fuse together , thus no netted structure are
formed as they are formed in articulate ducts
The walls of the ducts are soft and very often thick
These may be or may not be branched
Branched nonarticulated laticifers commonly occur in
leaves. here they travel through the vascular bundles ramify
in the mesophyll and often reach the epidermis
Unbranched non-articulated laticifres of Vinca and
Cannabis occur in the primary phloem but are apperently
absent in the secondry tissue
15.
16. Types of Nonarticulate latex ducts /
latex cells
Non articulated unbranched laticifer
Non articulated branched laticifer
17. a. Non-articulate unbranched
laticifers
They develop into long ,more or less
straight tubes
Eg:- Cannabaceae (Humulus , Cannabis)
Apocynaceae (Vinca)
Urticaceae (Urtica)
18. b. Non articulated branched
laticifers
They branched repeatedly, each cell thus
forming an immense system of tubes
Eg:- Asclepiadaeae (Asclepias, Cryptostegia)
Euphorbiaeae (Euphorbia)
Moraceae ( Ficus, Morus)
Apocynaceae( Nerium oleander)
Cyclanthaceae( Cyclanthus bipartitus)
19. Articulate latex ducts/ Latex
vessels
Compound in origin : made up of number of cells, joined
end to end to form longitudinal files of cells
These are living coenocytic cells
Initiation takes place in the ontogeny of plant
Resembles with xylem vessels ; joined together with end
walls dissoled
Eg- Compositae, Euphorbiacece, Papaveraceae ,
Moraceae
Laticifer show various arrangement and a frequent
association with the phloem
20. Articulate latex ducts
In Carica papaya the laticifer apparently
occur not only in the phloem but also in
the xylem
21. First pic shows both non articulate and articulate laticifers
second shows only articulate laticifers
24. a.Articulated nonanastomosing
laticifers
They consist of a series of long cell chainsor
compound chains or tubes not connected with
each other laterally
Eg:- Papaveraceae (Chelidonium)
Convolvulaceae(Convolvulus,Dichondra)
Sapotaceae (Achrassaota, Manilkarazapota)
Musaceae (Musa)
Liliaceae (Allium)
25. b. Articulated anastomosing
laticifers
They form lateral anastomes with similar
cell chains or tubes, all united into a
netlike structure or reticulum
Eg:-Caricaceae (Carica papaya)
Euphorbiaceae (Hevea, Manihot)
Papaveraceae (Argemone,Papaver)
26. Lithocysts
Cystolith which is a botanical term for outgrowths
of the epidermal cell wall , usually of calcium
carbonate , formed in a cellulose matrix in
special cells called Lithocysts , generally in the
leaf of plants
it includes in genera of Acanthaceae
plants in the family Urticaceae also form leaf
cystolith , but only during their later flowering
seed setting stages
also in plants of family Cannabaceae- Cannabis
and Moraceae – Ficus elastica