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MOLYBDENUM DEPENDENCE, NITRATE UPTAKE AND PHOTOSYNTHESIS OF FRESHWATER PLANKTON ALGAE 1, 2
Author(s) -
Wallen D. G.,
Cartier L. D.
Publication year - 1975
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1975.tb02794.x
Subject(s) - chlamydomonas reinhardtii , biology , photosynthesis , algae , nitrate , chlorophyll , molybdenum , botany , chlorophyll a , zoology , ecology , biochemistry , chemistry , inorganic chemistry , gene , mutant
SUMMARY The effects of molybdenum on photosynthesis and nitrate uptake by two species of freshwater algae, Navicula pelliculosa (Bréd.) Hilse and Chlamydomonas reinhardtii Dang. Were examined. Photosynthetic rates in cells of N. Pelliculosa deprived of Mo for 48 h were significantly lower than in nondeprived cells; the rates were 2.6 and 4.5 μg C/10 6 cells/h, respectively. There was no significant reduction in photosynthetic rates of C. reinhardtii under the 2 treatments, the rates were both ca. 6.0 μg C/10 6 cells/h. These observed rates in the 2 species were not altered by added Mo concentrations as high as 1.0 ppm. The chlorophyll a values in 48 h Mo‐deprived cells were 1.15 μg/10 6 cells compared to 1.57 μg/10 6 cells provided with this metal. Molybdenum deficiency did not affect the chlorophyll a concentration in Chlamydomonas; the chlorophyll levels were 2.44μg/10 6 cells. Nitrate uptake by Mo‐deprived cells of N. Pelliculosa was significantly lower than in cells cultured in Mo; the rates were 0.087 and 0.238 μM NO a − /10 6 cells/h, respectively. Uptake rates by C. reinhardtii were similar with or deprived of Mo. The K m values for No 3 − uptake were 14.9 and 148.0 μM for N. Pelliculosa and C. reinhardtii, respectively.