TIME, PLANT GROWTH, RESPIRATION, TEMPERATURE 9
Figure 3 Leaf tissue was cut from Distichlis spicata(L.) Greene growing on a salt playa near Goshen, Utah.
Plant collections were made during May, June, and August of 1997 from soil relatively high and low in NaCl.
Isothermal calorimetric measurements were made at 25°C. (A) Metabolic heat rates (q). (B) Respiration rates
(RCO2). (C) Ratio of metabolic heat rate to respiration rate (q/RCO2) or energy efficiency. Smaller numbers in-
dicate greater efficiency. (D) Predicted specific growth rate (HBRSG). (From Ref. 38.)
Figure 4 Salicornia utahensisTidestr. was grown in several concentrations of NaCl at temperatures ranging
from 5 to 45°C. Specific growth rate, HBRSG, calculated from metabolic heat and CO 2 rates is plotted as a
function of the salt concentration in the growth medium.