DURATION OF EMBRYOGENESIS AT DIFFERENT TEMPERATURE IN BACTERIOVOROUS NEMATODE: TERATORHABDITIS PALMARUM

Embryogenesis of the free-living nematode Teratorhabditis palmarum (Gerber & Giblin-Davis, 1990) was followed by a single-cell zygote to a fully formed individual just prior to hatching. Cell fates are generally highly resolved and the timing of cell division is more or less constant from individual to individual. Generally nematodes undergo cleavage soon after the fertilization and among them there is lot of variation in time. The time course of subsequent cleavages, soon after the fertilization is meticulously orchestrated, including reproducible division timing. First cleavage is always transverse that result in unequal blastomeres having anterior one larger and posterior one smaller. It was followed by successive oblique divisions. Just prior to fertilization, the rate of pronuclear fusion that consists of fusion of oocyte pronucleus with the sperm pronucleus was found to be 1 hr at 14 ± 1⁰C, 45 minutes at 20 ± 1⁰C and 30 minutes at 25 ± 1⁰C. The duration of complete embryogenesis in T. palmarum at 15 ± 1⁰C, 20 ± 1⁰C and 25 ± 1⁰C temperature was found to be 32.3 h, 25.2 h & 21.1 h respectively. It was confirmed in the present work that temperature had a significant role in the duration of embryogenesis. Key Words: Embryogenesis, T. palmarum, cleavage, temperature