EMBRYO CULTURE :- "The embryo of different developmental stages, formed within the female gametophyte through sexual process, can be isolated aseptically from the bulk of maternal tissues of ovule, seed or capsule and cultured in vitro under aseptic and controlled physical conditions in glass vials containing nutrient solid or liquid medium to grow directly into plantlet."

2. EMBRYO CULTURE
EMBRYO CULTURE :-
"The embryo of different developmental stages, formed
within the female gametophyte through sexual process,
can be isolated aseptically from the bulk of maternal
tissues of ovule, seed or capsule and cultured in vitro
under aseptic and controlled physical conditions in glass
vials containing nutrient solid or liquid medium to grow
directly into plantlet."
DIFFERENT CATEGORIES OF EMBRYO CULTURE:-
1.Culture of mature and intact seed embryo :-
The aim of this embryo culture is to analyse the var-
ious parameters of embryonic growth and the
metabolic and biochemical aspects of dormancy and
germination.

3. 2. Culture of surgically dissected embryos:- The
mature seed embryo can be dissected surgically into
a number of segments. Such embryo segments are
cultured to analyse the rela- - tionship of different
parts of the embryo to its final form in culture.
3.Culture of immature embryos or proembryos:-
Globular and heart-shaped stages of embryo are
appropriately called as pro- embryos. The objective
of such culture is to understand the control of
differentiation and the nutritional requirements of
such progressively developing embryos.
4. Culture of intact seed containing undifferentiated
embryo:- Each fruit of an orchid
plant develops sev- eral thousand tiny seeds which
contain morpho- logically undifferentiated embryos.
These em- bryos are the spherical mass of tissue
lacking both radicle and plumule. There is even no
stor- age tissue in the seeds and the seed coat is re-
duced to a membranous structure. For this reason,
the entire seed of orchid containing undifferentiated
embryo is cultured and treated as embryo culture.

4. 5. Culture of adventive embryo from polyemryonic
seed:-
Besides the zygotic embryo produced from egg cell, some
additional embryos are produced from nucellar tissue in
polyembryonic seed like lemons and oranges. Such
additional abortive embryos can be exploited in culture
for clonal propagation.
6. Culture of inviable or abortive embryo:-
In many inter-specific or intergeneric breed- ing
experiments, sometimes inviable or abortive embryos
may develop due to unsuccessful cross- es. As a result,
the non-viable seeds do not ger- minate normally. But it
is now possible to raise a hybrid plant by culturing the
inviable embryos in vitro.
PRINCIPLE OF EMBRYO CULTURE:-
The underlying principle of the method is the aseptic
excision of the embryo and its transfer to a suitable
nutrient medium for development under optimum
culture conditions.
PROTOCOL:-

5. The following protocol for embryo culture is based on
the method used for Capsella bursa-pastoris. With
modification, this basic protocol should be applicable to
embryo culture in general.
STEPS :-
1. Capsules (dry fruit or a capsule is a structure
composed of two or more carpels.) in the desired stages
of development are surface sterilized for 5-10 minutes in
0.1% HgCl2, either in a closed small room previously
illuminated by UV lamps or in a Laminar air flow.
2 . Further operations are carried out under a specially
designed dissecting microscope at a magnification of
about 90X. The capsules are kept in a depression slide
containing few drops of liquid medium.
4. The outer wall of capsule is removed by a cut in the
region of the placenta; the halves are pushed apart with
forceps to expose the ovules.
5. A small incision ( micropyle) in the ovule followed by
slight pressure with a blunt needle to free the embryos.
6. The excised embryos are transferred by mi-
cropipettes or small spoon headed spatula to standard

6. 10 cm petridishes containing 25 ml of solidified standard
medium. Usually 6-8 embryos are cultured in a petridish.
7. The pertridishes are sealed with cellotape to prevent
desication of the culture.
8. The cultures are kept in a culture room at 25± 1°C and
given 16 hrs. illumination by cool white fluorescent tube.
9. Subcultures into fresh medium are made at
approximately four weeks intervCULTURE
( note :- for fresh seeds or dry and imbibed seeds
the schedule is slightly changed.
1. Seeds are cleaned by 5% Teepol (a liquid detergent)
for 10 minutes
2. dipped in 70% ethyl alcohol for 60 seconds.
3. Surface sterilization in 0.1% HgCl, is followed by
washing in sterile water.
4. Then the seeds are decotylated using a sharp scalpel
and embryos are transferred to solid nutrient medium.
ROLE OF SUSPENSOR IN EMBRYO CULTURE:-
)

7. The suspensor is traditionally believed to be a supporting
structure during plant embryo development that pushes
the embryo proper into the endosperm cavity and
connects it to the surrounding maternal and endosperm
tissues to facilitate the transfer of nutrients and plant
hormones.
APPLICATION OF EMBRYO CULTURE IN PLANT SCIENCE:-
Importance of embryo culture in relation to biological
knowledge:-
• It helps determining the factors that regulate the
growth of the primodial organs of the seedling plant.
• It helps to study the metabolic and biochemical
aspects of dormancy and germi- nation.
• It helps in analysis of various parameters of
embryonic growth.
• The culture of proembryos helps to understand the
control of differentiation and the nutritional
requirements of progressively smaller embryos.
• The culture of surgically dissected embryos
segments has facilitated understanding the

8. relationship of the different parts of the em- bryo to
its final form in culture.
Applied aspect of embryo culture:-
❖ Culture of non- viable or abortive embryo
❖ To overcome seed dormancy
❖ To shortening the breeding cycle
❖ To overcome self sterility of seeds
❖ Seed testing.
Other applications:-
❖ To study the evolutionary relationship.
❖ To study the host parasitic interaction.
❖ To study the mutagenic effect.