Compensatory Growth Of Phaeodactylum Tricornutum In Response To The Stress Of Nutrients Limitation

Phaeodactylum tricornutum belongs to Bacillariophyta, Pennatae, Phaeodactylales,Phaeodactylaceae, Phaeodactylum, which is a sort of marine micro-algae with lots of higheconomic value. Compensatory growth of P. tricornutum was analyzed and determined undernitrogen, phosphorus and total nutrients limitation for studying the growth of P. tricornutum inresponse to the stress of special nutrients limitation and the compensatory growth effects afterthe nutrients recovery. The stresses of nutrients limitation included nitrogen, phosphorus andtotal nutrients limitation three treated groups in this paper, and every group included fiveconcentration levels, while f/2 culture medium was served as the control. The time was 10 daysfor nutrients limitation and 16 days for nutrients recovery. Cell density, biomass, content ofintracellular protein and soluble carbohydrate were analyzed and determined. The results show:(1) The sensitivity of P tricornutum in response to the three stresses of nutrients limitation for 10days were significant. The growth of P tricornutum and accumulation of intracellular substancewere restrained markedly (p＜0.05). And along with the aggravation of three nutrient stressesintensity, cell density, biomass and content of intracellular protein were lower and lower. (2)During nitrogen and phosphorus recovery stages, the relative heavy stress treatments such as1/20N, 1/10N, 1/8N, 1/20P, 1/10P and 1/8P showed remarkable over-compensatory growth effectincluding more celldensity, biomass and cell average relative growth rate than the control(p＜0.05). (3) During total nutrients recovery stage, 1/20T, 1/10T, 1/8T and 1/4T four stresstreatments showed remarkable over-compensatory growth effect including more cell density,biomass and cell average relative growth rate than the control (p＜0.05). It was obvious that P.tricornutum showed the ability of over-compensatory growth in the course of recovery growthunder the stress of special nutrients limitation. (4) During the nutrients recovery stages, thedifference of content of intracellular protein and carbohydrate between nutrients stress treatmentsand the control was not significant, as shows that P. tricornutum has the ability of exactcompensatory accumulation including intracellular protein and soluble carbohydrate after thenutrients recovery.