Changes in body fluids of burrowed spadefoot toads as a function of soil water potential
McClanahan L. 1972. Changes in body fluids of burrowed spadefoot toads as a function of soil water potential. Copeia. 1972(2):209-216
Spadefoot toads (Scaphiopus couchii) were allowed to burrow in soils having different water potentials. Samples of plasma and urine were obtained initially and at various time intervals throughout the experiment and analyzed for electrolytes, urea, and total solute concentration. In addition, weight changes and changes in volume of bladder urine stored were determined. The rate of production of urea in burrowed toads is apparently a function of soil water potential. Toads kept in soil with a low water availability produced urea at a higher rate than toads kept in soil of high water availability. This is interpreted as an adatption allowing a toad to change its body water potential and decrease the water potential gradient between toad and soil. If the toad's water potential is lower than the soil's, the gradient will favor the uptake of water by the toad. Plasma K+ was closely regulated in burrowed toads, whereas plasma Na+ was rather variable, but generally increased in toads burrowed in soil of high moisture tensions.