In total, ten navel oranges were monitored over a 24 hour
time course. Flux rates were similar for all ten oranges
measured with the multiplexed flask system, as shown in
panel A of Figure 13. The rates declined steadily
throughout the measurement period for all samples, and
tracked a decline in chamber air temperature (Figure
13B). The decrease in respiration rate was well correlated
(r
2
= 0.7893) with chamber air temperature over the
measurement period (Figure 13C), and is likely due to
decreased metabolic activity within the fruit as it cooled
(based on chamber air temperature Q
10
=7.8).
Conclusions
The LI-8150 multiplexer is a highly adaptable instru-
ment. When configured for multiplexed flask measure-
ments it provides a means of rapidly sampling CO
2
fluxes
from multiple samples, and tracking fluxes over long
time courses. While in the example shown we monitored
respiration of detached fruit, similar systems have been
applied in monitoring insect respiration (Nestel et al.
2007), respiration of isolated soil samples (Jones and
Kielland 2002, Haney et al. 2008), and monitoring
carbon fluxes from attached leaves and fruit (Araki et al.
1998, Kitano et al. 1997).
References
Araki, T., M. Kitano, M. Hamakoga, and H. Egughi.
1998. Analysis of growth, water balance and respiration
of tomato fruits under water deficit by using a multiple
chamber system. Biotronics 27:61-68.
Haney, R., W. Brinton, and E. Evans. 2008. Soil CO
2
respiration: Comparison of chemical titration, CO
2
IRGA analysis and the Solvita gel system. Renewable
Agri. And Food Sys. 23:171-176.
Jones, D. and K. Kielland. 2002. Soil amino acid turnover
dominates the nitrogen flux in permafrost-dominated
taiga forest soils. Soil Bio. & Biochem. 34:209-219.
Kitano, M., T. Araki, M. Hamakoga and H. Eguchi. 1997.
On-line measurements of CO
2
and H
2
O gas fluxes, sap
flux and expansive growth in an intact tomato fruit.
Biotronics 26:85-94.
Nestel, D., E. Nemny-Lavy and V. Alchanatis. 2007. Gas-
exchange patterns of Mediterranean fruit fly pupae
(Diptera: Tephritidae): a tool to forecast developmental
stage. Florida Entomologist 90:71-79.
Figure 14.
Multiplexed flask system as described in this document. Note that the LI-8100A Analyzer Control Unit is
required, as well, but not pictured above.
10
