PJB-1978-14
Comparatively effects of pressure , tempareture and oxygen tension on photosynthetic and respiratory rtaes in porphyra umbilicalis (L )J, Ag.
Mustafa shameel
Abstract
Influences of hydostatic pressure
(600atm) , temperature (50, 150 and 300
C ) and O2 concentration (3 410 % of air saturation ) of the outer medium were studied on the rate of O2 exchange of porphyra umbilicalis collected from heligoland (north sea ) . the O2 tension acted antagonistically to the pressure effects. The pressure influenced rates
of respiration and apparent photosynthetics decreased gradually with a decrease in the O2 concentration and vice versa ; the effects on photosynthesis, however, were lesser than those on respiration. The O2 concentration of 30% was found to be critical, at higher values repiration of the pressure affected algae increased
whereas at lower values it decreased as compared to control . At O2 concentration lower than 15% , the
rate of O2 exchange decreased very sharply . the pressure influences were retarded by higher and intensified by lower temperatures.
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