EFFECT OF TEMPERATURE AND FOOD CONCENTRATION ON RESTING EGG FORMATION OF FRESHWATER ROTIFER BRACHIONUS CALYCIFLORUS

The effect of temperature and food concentration on resting egg formation of freshwater rotifer Brachionus calyciflorus was studied by accumulative population culture under 9 treatments of 3 temperature gradients (20℃, 25℃ and 30℃) and 3 food concentration gradients (1.5 ×106cells / mL,3.0 ×106cells / mL and 6.0 ×106cells /mL). The results showed that under the culture condition of temperature 20℃ and food concentration 6.0×106cells / mL, the production and formation efficiency of resting egg were 2032.33±141.50 ind./(10mL. 13d) and 2.61±0.18 ind./106cells algae, respectively, and were both biggest among all the conditions. This condition was optimal for mass production of resting eggs. At temperature 25℃ and 30℃, the food concentration of 6.0 ×106cells / mL and 3.0 ×106cells / mL was also optimal for the production of resting eggs, respectively. At the temperature 20℃, the mixis rate was bigger than that of 25℃ and 30℃. There was no significant effect of temperature,food concentration and their interaction on the fertilization rate.