ISSN:
1432-072X
Keywords:
Cyanobacterium
;
Adaptation
;
Photosynthesis
;
Carbohydrate accumulation
;
Relative growth rate
;
[Light-phosphate] interactions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The cyanobacterium Oscillatoria agardhii was grown in continuous culture under various light conditions in order to study the interactions of light on phosphorus-limited growth. Under severe P-limiting (light-saturating) conditions, a low chlorophyll a and C-phycocyanin content was found. In addition, the light-harvesting capacity, reflected in the values of P max (maximum light-saturated oxygen production rate) and α (photosynthetic affinity), were low compared to light-limited cultures. Reduction of the light climate, either by reduction of the length of the photoperiod or light-intensity, resulted in an increase in light-harvesting capacity (higher pigment content, P m and α) during growth under P-limiting conditions. Light-induced changes in P max and α could be related to the relative growth rate, being the actual growth rate as a fraction of the growth rate which would be observed under light-limiting conditions. Under P-limiting conditions, reduction of the light-climate caused a reduction in dry weight of the culture. This decrease was mainly due to a decrease in carbohydrate content of the cells. Under all conditions tested, carbohydrates were found to accumulate during the light-period and to be consumed during the dark-period. Evaluation of carbohydrate consumption in the dark yielded a specific maintenance rate constant of 0.001 h-1. This observation leads to the conclusion that the specific maintenance rate constant is independent on the character of the growth rate limiting nutrient for O. agardhii.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00409239
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