Agriculture Reference
In-Depth Information
when excised unfertilized ovaries from inflorescence segments were transferred
from MS + BAP (8.5 µM) + 2,4-D (4.5 µM) to MS + 2,4-D (4.5 µM) + Glycine
(6660 µM) + Proline (1738 µM).
3.4.4 Carbon Source
Sucrose has generally been used as the major carbohydrate source in the culture
medium. Sucrose concentration in induction medium has a major effect on osmosis,
and the development of embryos is apparently influenced by osmosis (Wakizuka
and Nakajima
1975
). The effect of sucrose on anther culture has been investigat-
ed in a number of species. The necessity of sucrose for successful androgenesis
was first demonstrated by Nitsch in 1969 for tobacco and later by Sunderland in
1974 for
Datura innoxia
. Generally, sucrose is supplied at 2-3 % concentration.
However, increase in its concentration can lead to beneficial morphogenic potential
(Agarwal et al.
2006
; Sopory and Munshi
1996
) by suppressing the proliferation of
anther wall (somatic tissues) (Ouyang et al.
1973
). For potato, 6 % sucrose proved
distinctly superior than 2-4 % sucrose in terms of the number of anthers forming
pollen embryos (Sopory et al.
1978
). High sucrose levels (6-17 %) are required in
Gramineae and Brassicaceae families in which mature pollen is shed in the tricel-
lular condition (Dunwell and Thurling
1985
), whereas for those in which mature
pollen is bicellular (e.g., Solanaceae), lower level of sucrose, such as 2-5 %, is
usually beneficial (Dunwell
2010
). All
Brassica
species require 12-13 % sucrose
for androgenesis in anther and pollen cultures. According to (Dunwell and Thurl-
ing
1985
), high sucrose concentration favours better survival of pollen grains, thus
improving the frequency of androgenesis in
Brassica napus
(Last and Bretell
1990
).
Wedzony et al. (
2009
) have reported the beneficial effects of maltose on androgen-
esis in anther cultures of wheat, triticale, rye and rice.
The type and concentration of sucrose used in the medium for inducing in vitro
gynogenesis varies from species to species. High sucrose concentration (8-10 %)
in the culture medium has been shown to be helpful in some species, like sweet po-
tato (Kobayashi et al.
1993
) and onion (Campion et al.
1992
), whereas in summer
squash, 9 % sucrose is detrimental for production of any embryos (Shalaby
2007
).
Sucrose concentration used in unfertilized ovary and ovule culture was 3 to 10 % in
barley, 4 to 8 % in wheat, 3 to 6 % in rice, 2 % in tobacco and 3 to 6 % in
Gerbera
(Yang and Zhou
1982
).
3.5 Culture Conditions
Pre-treatments, such as chilling, temperature shock, high humidity, water stress, an-
aerobic treatment, centrifugation, sucrose, nitrogen starvation, ethanol, gamma ra-
diation, microtubule disruptive agents, electrostimulation, high medium pH, heavy
