This ppt was prepared for class seminar according to the syllabus of college.It contains brief history, description of plant, morphology evaluations, hemp fibre and its processing, surgical dressing, chemical test and uses. References are added as well.

1. Cannabis

2. HISTORY
• Cannabis is indigenous to Central
Asia and the Indian
subcontinent.Hemp is possibly
one of the earliest plants to be
cultivated.
• For millennia, the plant has been
valued for its use for fiber and
rope, as food and medicine, and
for its psychoactive properties for
religious and recreational use.

3. INTRODUCTION
•The genus Cannabis (family Cannabaceae) is
a cosmopolitan species which is widely
distributed around the world.
•Cannabis sativa L. is a dioecious (unisexual)
species, where individual plants develop only
male or only female reproductive organs
(flowers).
•Staminate (male) plants are usually taller but
less robust than pistillate (female) plants.
Stems are erect and can vary from 0.2-6 m.
The plant height, depends on environmental
and hereditary factors as well as the method of
cultivation.
• The flowers of the female plant are arranged
in racemes and can produce hundreds of
seeds. Male plants shed their pollen and die
several weeks prior to seed ripening on the
female plants.

5. ACTIVE COMPOUNDS
• Main psychoactive constituent of Cannabis is
tetrahydrocannabinol (THC), the plant is
known to contain more than 500 compounds,
among them at least 113 cannabinoids.
• Another cannabinoid produced in high
concentrations by some plants is cannabidiol
(CBD), which is not psychoactive but has
recently been shown to block the effect of
THC in the nervous system.
• Cannabinoids are found in the highest
concentration in the leaves and flowers.
• It includes about 120 compounds responsible
for its characteristic aroma. These are mainly
volatile terpenes and sesquiterpenes.
• The high lipid-solubility of cannabinoids
results in their persisting in the body for long
periods of time.

6. ACTIVE COMPOUNDS

7. MACROSCOPIC CHARACTERS
• Stems are green, erect, hollow and longitudinally
grooved (figure 6). They can vary from 0.2-6 m,
although most of the plants reach heights of 1-3 m.
• The leaf is palmate and consists of 3-9 linear-
lanceolate leaflet blades. The margins are coarsely
serrated, the teeth pointing towards the tips; the veins
run out obliquely from the midrib to the tips of the
teeth. The lower (abaxial) surfaces are pale green with
scattered, white to yellowish brown, resinous glands.
• Each staminate (male) flower consists of five whitish-
green minutely hairy sepals about 2.5-4 mm long and
five pendulous stamens, with slender filaments and
stamen.
• The pistillate (female) flowers are more or less sessile
and are borne in pairs. Each flower has a small green
bract enclosing the ovary with two long, slender
stigmas projecting well above the bract.
• The fruit, an achene, contains a single seed with a hard
shell tightly covered by the thin wall of the ovary,
ellipsoid, slightly compressed, smooth, about 2-5 mm
long, generally brownish and mottled. The fruit is
commonly regarded as a seed.

8. MICROSCOPIC CHARACTERS
Cannabis sativa can be identified by microscopic structures on the surface of the plant, namely, by
trichomes .Two types of trichomes occur-
(a) Non-glandular trichomes are numerous, unicellular, rigid and curved hairs, with a slender pointed
apex:
• Cystolithic trichomes found on the upper surface of the cannabis leaves have a characteristic bear
claw shape and may have calcium carbonate crystals (cystoliths) visible at their bases. Frequently, the
trichome is broken and the cystolith freed;
• Non-cystolithic trichomes occur mainly on the lower side of the leaves, bracts and bracteoles and
lack the enlarged base;
• The simultaneous presence of these bear claw-shaped trichomes on the upper surface and the fine,
slender non-cystolithic trichomes on the lower surface of the leaves is a characteristic of cannabis.

9. (b) Glandular trichomes. They occur
as:
• Sessile glands, i.e. trichomes without
stalk, which are generally found on
the lower epidermis;
• Small bulbous glandular trichomes
with one-celled stalks;
• Long multicellular stalks on the
bracteoles surrounding the female
flowers (multicellular stalked
glandular trichomes).
Fig : Cross section of bract from the fruiting plant.

10. Colour Test -
1.Fast Corinth V salt test on a filter paper - A purple red coloured stain at the
centre of the filter paper is indicative of a cannabis containing product.
2.Fast Blue B salt test (on a filter paaper) - a purple red coloured stain at the
centre of the filter paper is indicative of a cannabis containing product.
•
CHEMICAL TEST

11. USES
• It can be refined into a variety of commercial items, including paper,
textiles, clothing, biodegradable plastics, paint, insulation, biofuel, food,
and animal feed.
• Pure hemp has a texture similar to linen. Because of its versatility for use in
a variety of products, today hemp is used in a number of consumer goods,
including clothing, shoes, accessories, dog collars, and home wares. For
clothing, in some instances, hemp is mixed with lyocell.
• Indian hemp (Cannabis sativa) fibers are made into cord and rope, and into
some textiles.Various items made from Indian hemp (Cannabis sativa),
including twine, purse, shoelaces, colored yarn, wallet, bracelet, and
notebook.

13. • Industrial cannabis is grown mainly for seeds, which are used in the
production of hemp oil, and hemp fibers for industrial applications.
• History for use as a food, fuel source, nutritional supplement, body care product,
source of paper, building material, medicine, and in textiles.
• Cannabis cultivation delivers environmental benefits. Cannabis plants produce
large amounts of aerial biomass, which protects soil against excessive drying and
limits weed growth.
• Cannabis roots are decomposed after harvest, they loosen the soil and constitute a
rich source of organic matter.

14. HEMP
• Hemp, or industrial hemp, is a strain of
the Cannabis sativa plant species that is
grown specifically for the industrial uses.
• It is prepared from pericyclic fibres of the
stem.
• It is one of the fastest growing plants and
was one of the first plants to be spun into
usable fibre 10,000 years ago.

15. PROCESSING
Hemp grown for fiber is harvested before flowering.
1.Retting – Retting is a process employing the action of micro-organisms and moisture
on plants to dissolve or rot away much of the cellular tissues and pectins surrounding
bast-fibre bundles, and so facilitating separation of the fibre from the stem.Once cut,
the plants, which are composed of two types of fiber – long outer fibers suitable for
textiles, and short inner fiber suitable for paper or industrial applications – are left in
the field for about 10 to 20 days to ‘ret’.Retting is of two types.
• Water Retting– It involves lying the stems in water in tanks, ponds or in streams for
around 10 days–it is more effective if the water is warm and bacteria-laden.
• Dew Retting– It is a natural process that is triggered by dew that falls on the crop
each morning. After cutting, the hemp stems were laid parallel in rows to dew ret.
The stems needed turning at least once (sometimes) twice in order to allow for even .
• Retting is complete when the fibre bundles appear white, separate from the woody
core and divide easily into individual finer fibers for their full length. Once this
process is complete (dry), the stalks are collected and sent to the “decortication”
machine.

16. 2. Decortication– In this process the de-leafed Hemp stems are then dried, i.e.
conditioned and freed from the wood kernel in a sequence of a squeeze, break and
scutching processes. In other words, it is described as breaking the stems by passing
through a “breaker” or fluted rollers. Then the fiber is separated from the woody core
(“scotching”) by beating the broken stems with a beech stick or passing through rotary
blades
3. Softening– By using a so-called Hemp softener or roller, the decorticated fibers are
made softer and suppler.
4. Combing– The shortening of the initial fiber lengths from up to 3 m down to 650 mm is
done on a special cutting machine. Then the short and tangled fibers are combed out, the
long fibers are parallelized and smoothed using a hackling machine. In other words
“hackling” (combing) means to remove any woody particles and to further align the fibers
into a continuous “sliver” for spinning.
5. Spinning– According to quality and the desired yarn fineness, spun into Hemp yarn by
wet or dry spinning processes.
The best yarns are obtained by wet spinning. In which fibers are allowed to pass through a
trough of hot water before being spun. This softens the Pectin allowing a greater drawing
out and separation of the fibers and producing a finer yarn (greater than 12 Nm). Dry
spinning is cheaper, producing yarns and fabrics with a different appearance and handle.

17. SURGICAL DRESSING
• Cotton up until the 19th century was
expensive so Hemp was cheap and
a very likely candidate for such use.
• Hemp is natural dressing obtained
from plant fibres.
• Pericyclic fibres of Cannabis sativa
stem.
• Mostly cellulose, minimal lignification.
• Fibre ends bluntly rounded, some
forked from injury.
• Lumen flattened or oval.

18. REFERENCES
1.Cannabis sativa L. – cultivation and quality of raw material
Article in Journal of Elementology · May 2018 DOI: 10.5601/jelem.
2017.22.3.1500.
2. Plant Fibers - W.P Armstrong (5 march 2010)
3.Pharmacognosy by S.B. Gokhale
4. Extraction, processing, properties and use of hemp fiber - Dr.
N.N.Mahapatra (28th May 2018).
5. Recommended Methods for the Identification and Analysis of Cannabis
and Cannabis Products - UNITED NATIONS New York, 2009