1.
Specialized Tissue Or Secretary
Tissue
Flower with Nector gland
Lactifer Tissue

2.
Specialized tissue or secretary tissue
• Cell or tissue which produce a variety of secretions in plant are called secretory
tissues.
• The secreted substance may remain deposited within the secretory cell itself or may
be excreted, that is, released from the cell.
• Substances may be excreted to the surface of the plant or into intercellular cavities
or canals.
• Some of the many substances contained in the secretions are not further utilized by
the plant (resins, rubber, tannins, and various crystals), while others take part in the
functions of the plant (enzymes and hormones).
• Secretory structures range from single cells scattered among other kinds of cells to
complex structures involving many cells; the latter are often called glands.
Resins
Latex produce From
Rubber Plant
Tannin from Plant Source

3.
• As a result of cellular processes, substances that are left to accumulate within the cell
can sometimes damage the protoplasm.
• Thus, it is essential that these materials are either isolated from the protoplasm in
which they originate, or be moved outside the plant body.
• Although most of these substances are waste products, some substances are vital to
normal plant functions. Examples: oils in citrus, pine resin, latex, opium(Poppy tears),
nectar, perfumes and plant hormones.
• Generally, secretory cells are derived from parenchyma cells and may function on their
own or as a tissue.
• Some product of secretory tissue having great commercial value.
Essential oil from Citrus
Opium Poppy (Papaver somniferum)
Pine Resin
Nector

4.
• There are a large number of plants in the world which have special cells or groups of cells that secrete or
excrete products from the plant body.
• The tissues that are concerned with the secretion of gums, resins, volatile oils, nectar, latex, and other
substances in plants are called secretory tissues.
• These tissues are divided into two groups.
1.Laticiferous tissue / duct
2.Glandular tissue / duct

5.
1. Laticiferous tissues
• These consist of thin walled, greatly elongated and much branched ducts containing a milky or yellowish coloured juice
known as latex.
• This mixture storage, generally milky white, other colours rarely, form an emulsion which are active ingredients as
protein, carbohydrates, enzymes, tannins, rubber, hormones and alkaloids and is called latex.
• A plant rich in latex is the papaya.
• They irregularly distributed in the mass of parenchymatous cells.
Laticiferous ducts are of two types:
1. Latex cell or non-articulate latex ducts
2. Latex vessels or articulate latex

6.
a) Latex cells
• Also called as "non-articulate latex ducts", these ducts are independent units which extend as unbranched structures
for long distances in the plant body.
• They originate as minute structures, elongate quickly and by repeated branching ramify in all directions but do not
fuse together. Thus, a network is not formed as in latex vessels.

7.
2. Glandular tissues
This tissue consists of special structures called the glands.
These glands contain some secretory or excretory products.
A gland may consist of isolated cells or small group cells with or without a central cavity.
There are of various kinds and may be internal or external.
Internal glands are:
Oil-gland secreting essential oils, as in the fruits and leaves of orange, lemon.
Mucilage secreting glands as in the betel leaf.
Glands secreting gum, resin, tannin etc.
Digestive glands secreting enzymes or digestive agents.
Special water secreting glands at the tip of veins.

8.
Oil-gland secreting essential oils, as in the fruits and leaves of orange, lemon

9.
Digestive gland in Insectivorous plant
Nepenthes Sundew Plant Venus Fly Trap Microscopic Image

10.
External glands are commonly short hairs tipped by glands. They are:
water-secreting hairs or glands.
Glandular hairs secreting gum like substances as in tobacco, plumbago etc.
Glandular hairs secreting irritating, poisonous substances as in nettles.
Honey glands as in carnivorous plants.

11.
• Lysigenous cavities are formed by cavities coming from cell groups which are loaded of
secretory products and whose protoplasm membranes have been destroyed gradually. This
group of cells is also called "pockets" of secretion and can be found in fruits and young stems
of citrus

12.
Schizogenous cavities are the cells or epithelial located inside the parenchyma tissue or inside
other tissues.
They always wrap rounded or irregular intercellular spaces, or intercellular ducts, simple or
branched, which sometimes go through all the plant as communications ducts.
These intercellular spaces are caused by separation of the glandular cells and are the containers
of the developed products; they are the schizogenous cavities or secretion cavities .
According to its contents, these are distinguished ducts or cavities with lipids (essential oils),
resins, gums and mucilage