Wainman, B.C., R.E.H. Smith, M.T. Arts
Abstract:
The fraction of recently produced photosynthate allocated to protein, carbohydrate, low molecular weight fractions and lipid varies with a number of environmental parameters. Allocation to lipid is a species specific phenomenon but increased lipid allocation content is associated nitrate and/or silicate deficiency, low temperatures and long days. We hypothesized that some of these trends should be apparent in large scale comparisons between salt and fresh water. To that end we collected a large amount of photosynthate allocation data gathered from natural assemblages of freshwater and saltwater algae that used similar collection, incubation and extraction methods. We found that protein allocation was inversely proportional to LMW allocation, carbohydrate allocation varied directly with daylength and, in most systems, protein allocation varied directly with temperature. Allocation to lipid was highly correlated with temperature in both fresh and salt water at temperatures less than 10 C. We suggest that the increase in lipid is a result of silicate and nitrate deficiency in chrysophytes and diatoms brought on by stratification of the water column that occurs at about 10 C.
(McMaster University, Hamilton, Ontario, Canada)
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