CO2 Enrichment
In a message dated 97-09-07 04:05:34 EDT, you write:
<< Does anyone have any advice on the use of CO2 enrichment on CAM-type
plant tissue cultures in the growth room?
We are considering the introduction of cylinder CO2 gas controlled by timer
and solenoid valves but with no sensor control. Haven't seen a mention of
CO2 enrichment on this listserv these last 12 months. Is it a discredited
practise in labs or not? Thanks.
Ron >>
Hi Ron:
CO2 enrichment does not appear to be a discredited practice at all. The
following article from the August, 1997 issue of Agricell Report may be of
interest
Ed Herman, Editor and Publisher
Agricell Report
PO Box 255
Shrub Oak, NY 10588
E-mail: agricell@aol.com
Phone/Fax: 914 528 3469
Ultra-High Levels of Carbon Dioxide Promote Plantlet Growth In Vitro=20
<>
<>A number of investigators have reported that increasing the level of carbon
dioxide above ambient conditions can stimulate growth of plantlets in vitro,
especially under high light intensities and in the absence of sugars or on
media containing low concentrations of sugars =97 conditions that lead to
photoautotrophic growth. These growth promotive effects, and the optimal
carbon dioxide levels required to achieve them, have been found to vary among
species. Using a passive diffusion continuous carbon dioxide flow-through
system, B. Tisserat and colleagues at the USDA=92s National Center for
Agricultural Utilization Research have now found that increasing the levels
of carbon dioxide to ultra-high levels (3,000 ml/liter) increases growth of
in vitro-cultured plantlets regardless of the sucrose levels as compared with
plantlets grown under normal atmospheric conditions (HortTechnology
7(3):282-289, 1997).
<> In the carbon dioxide flow system developed by the authors, carbon dioxide
and air are mixed in a flowmeter, pass through a hydrator and then enter a
chamber containing tissue culture vessels. The chamber is constructed from a
transparent polycarbonate box, modified to allow for the inflow and
evacuation of gases. Using this system, Tisserat et al. tested the in vitro
growth of carrot (Daucus carota), Citrus macrophylla, kale (Brassica
oleracea), lettuce (Lactuca sativa), radish (Raphanus sativus) and tomato
(Lycopersicon esculentum) plantlets on medium containing 0%, 0.3%, 1% and 3%
sucrose in flow chambers containing 350, 750, 1,500, 3,000, 10,000, 30,000
and 50,000 ml CO2/liter. The authors found that, whereas high (750-1500
ml/liter) concentrations of carbon dioxide tend to enhance the growth of
plantlets in vitro, ultra-high levels are consistently and particularly
advantageous for in vitro growth regardless of the amount of sugar in the
culture medium. For example, under 30,000 mL carbon dioxide/liter, the fresh
weight of lettuce plantlets grown on medium containing no sucrose is 11 times
that of plantlets grown under ambient carbon dioxide levels and the fresh
weight of those grown on medium containing 3% sucrose is 13 times that of
lettuce plantlets grown under ambient carbon dioxide levels. Similar
increases are obtained with carrot, citrus, kale, radish and tomato plantlets
grown at ultra-high carbon dioxide concentrations.
<> Tisserat et al. state that their passive diffusion continuous flow-through
system is inexpensive, easily constructed, and allows traditional tissue
culture vessels to be used by commercial and research laboratories for
testing ultra-high carbon dioxide levels on plant culture growth in vitro.
They add, "Ultra-high levels of carbon dioxide may completely eliminate the
requirement of an external carbohydrate source for culture survival and
optimal growth."
<prop>
<prop>For further information:
<prop>B. Tisserat, USDA-ARS, National Center for Agricultural Utilization
Research, Fermentation Biochemistry Research, Peoria, IL 61604, U.S.A.