Impact of light intensity on growth and levels of photosynthetic pigments of Gracilaria chouae

The impact of light intensity on growth and biomass of Gracilaria chouae were studied under laboratory conditions.It was found that G.chouae could not keep long term growth at a low light intensity(40 μ mol/m2.s).In a short time(7d),G.chouae achieved the rapidest grow that 80～120 μ mol/m2.s,and the content of photosynthetic pigment was greater than the other treatments.In a longer period(14～28d),the relative growth rate and the content of photosynthetic pigment of G.chouaeincreased with higher light intensities.Their dry weight reached the peak at 200 μ mol/m2.s.The highest photosynthetic rate and respiration rate of G.chouae were obtained at 0.40±0.12 μ mol O 2/g.s,and 0.07±0.03 μ mol O 2/g.s respectively.The light saturation and compensation points of G.chouae were 200±60 μ mol/m2.s and 35±15 μ mol/m2.s,respectively.