EFFECTS OF TEMPERATURE, LIGHT-INTENSITY, SALINITY AND SOURCE OF NITROGEN ON THE GROWTH, TOTAL LIPID AND FATTY-ACID COMPOSITION OF ULVA-PERTUSA KJELLMAN (CHLOROPHYTA)
Eat. Floreto et al., EFFECTS OF TEMPERATURE, LIGHT-INTENSITY, SALINITY AND SOURCE OF NITROGEN ON THE GROWTH, TOTAL LIPID AND FATTY-ACID COMPOSITION OF ULVA-PERTUSA KJELLMAN (CHLOROPHYTA), Botanica marina, 36(2), 1993, pp. 149-158
Growth, total lipid content and fatty acid composition of Ulva pertusa
Kjellman were studied in a 4 x 2 factorial laboratory experiment at t
wo levels (low and high) of temperature (15 and 25-degrees-C), subsatu
rating light intensities (16 - 32 and 48 - 64 muE m-2 s-1), salinity (
20 and 359 parts per thousand) and two sources of nitrogen (nitrate an
d ammonia). Specific growth rate (SGR) was highest at low temperature
(15-degrees-C), high light intensity (48 - 64 muE m-2 s-1) and high sa
linity (35 parts per thousand). Interaction between temperature, light
intensity and nitrogen source was the highest source of variation in
SGR at the beginning of culture, while salinity and salinity-light int
ensity interactions were the most limiting factors during the later pa
rt of culture. Effect of nitrogen source (with a preference for ammoni
a) was significant only during the early part of culture. Moisture con
tent was increased at low light intensity. Total lipid content (both a
s percent of fresh and dry weights) increased at low temperature and h
igh salinity. Low temperature increased levels (as % of total fatty ac
ids) of oleic (18 : 1n-9) and linolenic (18 : 3n-3) fatty acids. High
light intensity increased levels of palmitic acid (16 : 0), the most a
bundant fatty acid. Low light intensity (16 - 32 muE m-2 s-1) increase
d levels of the tetra-unsaturated fatty acids 16 : 4n-3 and 18 : 4n-3.
High salinity increased the levels of the C16 and C18 poly-unsaturate
d fatty acids.