Seeds

1. Lecture -1
Dr. Ahmed M. Metwaly

2. Outlines
 Introduction
 Linseed

3. THE SEED
 Definition:
 A mature fertilized ovule containing an embryo.
 The function of the seed is to ensure the continuation and
distribution of the plant.

4. Origin of the Seeds:
• The seeds are originated from fertilized ovules.
• The different types of ovules give different forms of
seeds.

5. Structure of the Ovules:
 1. The Nucellus:
 • A mass of parenchymatous tissue harboring a large cell called
the embryo sac and surrounded by integuments.
 2. The Integuments:
 • The nucellus is enveloped by two coats called integuments,
which, with the exception of a narrow opening called the micropyle,
completely envelope the nucellus.
 3. The Chalaza:
 • It is the swollen basal part of the nucellus from which arise the
integuments.
 4. The Embryo Sac:
 • It is a large cell containing 7 or 8 nuclei, grouped as follows:
 o Antipodal cells, Two nuclei (polar nuclei) and Egg apparatus:

6. Structure of the Ovules:

7. Types of Ovules

8.  1. Atropous or Orthotropous:
 In which the growth is uniform, the ovule is straight, having
funicle, chalaza and micropyle on one straight line and the
micropyle is lying at the extreme apex opposite to the funicle or its
scar, the hilum, which is immediately above the chalaza.
 This is not a common type, as in Piperaceae, and shows no raphé.
 2. Anatropous:
 This is the most common type, in which the ovule is inverted i.e.
bent upon the funicle and fused with it, so that the micropyle is near
the placenta and the raphé runs from one end to the other.
 Examples of this type are Zingiberaceae and Linaceae.

9.  3. Amphitropous:
 In which the body of the ovule is partly bent, so that the micropyle
and the chalaza are on a line at right angle to the free funicle or hilum. In
this case, the raphé runs from the chalaza to half the distance to the
micropyle and the chalaza. Micropyle and hilum are widely separated.
 Example of this type is Colchicum.
 4. Campylotropous:
 In the three previous types, the nucellus is straight. In this type, the
nucellus is curved, due to rapid growth of one side of the nucellus and
chalaza and coats on the same side. As a result, the ovule is bent upon itself
instead of upon the funicle so that the funicle, chalaza and micropyle are
all close to one another and there is no raphé as in Cruciferae and
Solanaceae.

10. Types of Ovules

11. Definition of Some Common Terms in
seed:
 1. The Hilum:
 It is a shallow pit, which is present on the surface of the
testa as a scar left at the point of attachment to the funicle.
 2. The Micropyle:
 It is present as a minute hole on the surface of the testa
corresponding to the micropyle of the ovule. In most cases it
is not easily detectable.
 3. The Raphé:
 It occurs as a raised line in the seeds derived from
anatropous or amphitropous ovules running from the hilum
to a raised point marking the chalazal end of the seed. Its
length varies, being about half the circumference of the seed
(anatropous ovule) or ¼ the circumference of the seed
(amphitropous ovule). It is absent in seeds derived from
atropous and campylotropous ovules. The raphé is a raised
line resulting from the fusion of the funicle with the
integuments.

12. Outgrowths of Testa:
 The testa, during the development of certain seeds, develops special
outgrowths, which are named differently according to their place of origin
and their nature.
 1. Arillus or Aril:
It arises from the funicle or from the tissue of the hilum and envelopes the
whole or part of the seed. It may be fleshy or membranous as in Cardamom.
 2. Arillode:
It arises from the tissue of the micropyle and covers part or whole of the seed.
 3. Caruncle:
It is a localized fleshy or spongy outgrowth, formed from the tissue in the
neighborhood of the micropyle and covers it as in Ricinus.
 4. Strophiole:
 It is a local enlargement over the position of the raphé e.g. Colchicum.
 5. Wing:
 It is a membranous extension of the testa e.g. Strophanthus.

13. Outgrowths of Testa:

16. Structure of the Seed:
 A typical seed consists of:
 The Testa: developed from the integuments of the ovule.
 The Embryo: developed from the fertilized ovum.
 The Endosperm: surrounding the embryo and developed from the
primary endosperm nucleus of the embryo sac.
 The Perisperm: formed from the nucellus.

17. Some Morphological Characters for Testa:
 A. The Texture:
 The texture of the testa may be:
 Membranous: As in Arachis seed & Almond.
 Leathery: As in Linseed.
 Hard: As in Nutmeg.
 Woody: As in Calabar beans.

18. B. The Surface:
 The outer surface of the testa shows diagnostic
features. It may be:
 Smooth: As in Linseed.
 Papillosed: As in Grains of paradise.
 Pitted: As in Mustard.
 Longitudinally striated: As in Almond.
 Reticulate: As in Stramonium.
 Hairy: As in Nux vomica.

19. The Perisperm:
 It is a developed form the nucellus. It may be:
 Membranous: As in Ricinus.
 Parenchymatous containing starch: As in Cardamom.
 Developing infoldings in the endosperm:As in Nutmeg

20. The Kernel:
 The kernel consists of all the tissues of the seed enclosed within the
testa. It may be formed of the embryo alone e.g. Mustard, or of
embryo accompanied by endosperm e.g. Ricinus, or by perisperm
and endosperm e.g. Cardamom.
 There are two kinds:
 Exalbuminous: In which the kernel consists of an embryo alone.
 Albuminous: In which the kernel consists of an embryo and
surrounded by endosperm or perisperm or both.
 The reserve materials are stored in the endosperm and/or
perisperm.

21. It is developed from the primary endosperm nucleus of the
embryo sac. It may be:
Starchy: As in Graminae.
Horny: With hemicellulosic walls as in Nux vomica.
Fleshy: As in Linseed.
Mucilaginous: As in Foenugreek.
Sometimes, the endosperm is very small and contains protein only,
either in minute aleurone grains or in amorphous masses as in
Zingiberaceae. In some cases, the outermost layer/layers of
endosperm are especially rich in protein in the form of minute
aleurone grains forming the aleurone layer.
3. The Endosperm:

22. Forms of The Embryo:
 The embryo may be:
 Straight as in Linseed, Strophanthus.
 Curved as in Papaver.
 Coiled or strongly curved as in Solanaceae.
 Bent on itself which may be:
 Incumbent: The radicle may be bent over against either one
of the straight cotyledons e.g. Cannabis.
 Accumbent: The radicle may be bent against the edges of
the two straight cotyledons e.g. Foenugreek.
 Orthoplocous: When the cotyledons in the incumbent
embryos are folded along their midribs so as to enclose the
bent radicle as in Brassica.

24. Linseed
 Names: Linseed, Flax Seed
‫الكتان‬ ‫بذر‬
 Origin: dried ripe seeds of
Linum usitatissimum Linne
Family: Linaceae.
 Linseed contains not more
than 2% of foreign organic
matters, and yields not less
than 30% of fixed oil.

25. Morphology
 Linseed has a very slight odor when
entire but the odor becoming
characteristic when crushed. It has a
mucilaginous oily taste.
 Shape: elongated ovate, compressed
to nearly flat rounded at one end
and obliquely pointed at the other.
Surface.
• The testa is leathery, glossy-brown, smooth and minutely pitted.
• The hilum and micropyle appear as a slight depression near the pointed end.
The raphé is present as a yellowish ridge along one edge running from the
hilum to the rounded end.
• Straight embryo.
• Albuminous seed
• The ovule was anatropous

26. TS

27. Key element of powdered linseed
Mat- like structure
Pigment layer

28. Constituents
 Fixed oil (30-
40%).
Linoleic acid (
Omega-6- fatty acid),
and
α-linolenic acid
(Omega-3 fatty acid)
and
oleic acid (Omega-3
fatty acids)
A triglyceride found in a linseed oil, a triester
(triglyceride) derived of linoleic acid, alpha-
linolenic acid, and oleic acid

29. Constituents
 Proteins (2%).
 A cyanophoric glycoside (linamarin).
 Acidic mucilage (6%).

32. Uses
 Omega-6- and Omega-3- fatty acid are essential
fatty acids causing a significant reduction of low
density lipoprotein (LDL) (the bad one) and increase
of high density lipoprotein (HDL) (the good one).
 They may be used to reduce the blood pressure,
decrease hypercholesterolaemia.
 Protection against angina and thrombosis as they
reduce the blood viscosity.
 Antioxidant effect.

33. Uses
 Recommended for colon discomfort.
 Demulcent drink (mucilage).
 In mild constipation cases, the laxative action is due to
increase in the volume of the intestinal bowel contents and
stimulation of peristalsis
Linseed is advisable with plenty of fluids, Why?
 Externally in the form of poultice, in liniments as antibacterial
for boils and carbuncles.
 The oil is good for bones, nails, teeth, and for healthy skin.
 The oil is used in painting .
 The linseed cake is a valuable cattle food.

36. Flax (linseed) production – 2016
Country
Production
(tonnes)
Russia 672,691
Canada 579,000
Kazakhstan 561,771
China 361,569
United States 220,480
India 125,000
World 2,925,282

37. Chemical Identification
 +ve sudan III due to V.O.
 +ve Ruthenium red due to acidic mucilage.
 Linamarin test (Cyanogenic glycosides)
(Guignard’s paper test)
(filter paper moistened with aqueous solution of picric
acid, then allowed to dry and dipped in aqueous
solution of sodium bicarbonate and dried

38. (filter paper moistened with aqueous solution of picric acid, then allowed to dry and
dipped in aqueous solution of sodium bicarbonate and dried

39. Questions ?
Dr. Ahmed Metwaly
Ass. Professor,
Faculty of Pharmacy,
Al-Azhar University,
Cairo, Egypt.