Culture Conditions For Regeneration And Development Of Segments Of Caulerpa Lentillifera

Seagrape（Caulerpa lentillifera）is one of edible green algae with high nutritionrequirements. The physio-ecological examination was conducted, with aim toexplore the asexual propagations on large scale, and the implementation ofvegetative reproduction in the future.Temperature, irradiance and salinity effects on the asexual reproduction of C.lentillifera were conducted; together with chlorophyll content, fluorescenceparameters and rbcL transcription. It was shown that the maximum specific growthrate (SGR) was at27.5℃and40μmol photons m-2·s-1, and warm temperature(25.0-30.0℃) could induce the formation of branches appearances. Both lower andhigher temperature could reduce chlorophyll content and decreased the Fv/Fm value,while high rbcL expressions occurred at27.5℃. With the irradiance rise, thechlorophyll content decrease, and the higher irradiance (100μmol photons m-2·s-1)is vital to the decreasing Fv/Fm and the increasing of NPQ value. The higherirradiance (40μmol photons m-2·s-1and100μmol photons m-2·s-1) also reduces therbcL expressions.To the wide algal survive salinity range of20-50‰, the proper salinity was30-40‰and maximum SGR of the alga occurred at35‰. Both the chlorophyllcontent and Fv/Fm reached maximum under35‰. Photosynthesis was inhibitedwhen the salinity were above45‰and below25‰respectively. Under the variousnutrition conditions, maximum SGR appeared at2.0mmol/L NO3-N concentrationand0.1mmol/L PO4-P concentration. However, maximum of chlorophyll contentoccurred at0.5mmol/L NO3-N concentration and0.1mmol/L PO4-P concentration. It reflected that the fluorescence parameters of PSII were strongly inhibited whenNO3-N concentration was above2.0mmol/L and PO4-P concentration was0.4mmol/L.Symmetry pattern of erect branch varied under different light density. Underhigh irradiance, replacement of ramuli followed radial symmetry, while it changedto be bilateral symmetry with low irradiance. Similar to the stolon apex, the ramulihad the capacity of developing into intact individual. The survival rate of stolonapex had linear relationship with the length. However, the rhizoid could not survivenor develop.