FERTILIZATION AND THE TEMPERATURE COEFFICIENTS OF OXYGEN CONSUMPTION IN EGGS OF ARBACIA PUNCTULATA

The eggs of A. punctulata have a high temperature coefficient in the resting state: Q (10) = 4.1. On fertilization and on cytolysis the temperature coefficient falls to less than half the resting value: Q (10) = 1.8 and 1.9 respectively. The factor by which oxygen consumption increases on fertilization is a variable, its magnitude depending on temperature as well as on egg species. It is nearly ten times greater at 11°C. and only double at 29.9°C. By extrapolating to 32°C. there would be no increase on fertilization. Critical thermal increments common to many oxidations, 6,500, 10,800, and 12,500, have been found. The possible significance of these results is discussed in relation to the catalytic mechanisms and structural organization of the egg cell.