[Morphological characteristics of resting eggs produced by different Brachionus calyciflorus].

ABSTRACT

In this paper, the Qingdao and Wuhu strains of Brachionus calyciflorus were cultured at 20 degrees C, 25 degrees C and 30 degrees C, and fed with 1.0 x 10(6) and 5.0 x 10(6) cells x ml(-1) of Scenedesmus obliquus. The morphological study of their produced resting eggs showed that at the two food concentrations, the resting eggs produced at 20 degrees C were the largest in length, width and volume, while those produced at 25 degrees C and 30 degrees C were the smallest. The effects of strain on the morphological characteristics of resting eggs also depended on food concentration. When the food concentration was 1.0 x 10(6) cells x ml(-1), the length, width and volume of the resting eggs produced by Wuhu strain and Qingdao strain were 156.00 microm, 99.95 microm and 12 269.11 microm3, and 145. 13 microm, 91.97 microm and 10 498. 19 microm3, respectively, while when the food concentration was 5.0 x 10(6) cells x ml(-1), the corresponding values were 155. 68 microm, 100.85 microm and 12 348.59 microm, and 156.63 microm, 98.04 microm and 12 054. 20 microm3, respectively. For test strains, only Wuhu strain showed a marked curvilinear correlation in the length, width and volume of its resting eggs with temperature. At the same temperature, the volumes of the resting eggs produced by both Qingdao and Wuhu strains were increased with increasing food concentration, with the exception that the resting eggs produced by Wuhu strain at 30 degrees C decreased with increasing food concentration.