SUMMARY. 



(1) An absorption apparatus and a constant-temperature incu- 

 bator are described suitable for use in the study of the respiration of 

 fruits. 



(2) Measurements are given of the rate of respiration at different 

 temperatures of many fruits — berries, peaches, apples, grapes, etc. 



(3) The respiratory intensity of these fruits varied greatly, but 

 when the data were plotted similarly shaped curves were formed. 



(4) No correlation between composition or size and respiratory 

 activity appeared. In general, however, fruits which grow and ma- 

 ture quickly and soon become overripe respire rapidly. This is true 

 of most of the small fruits. On the other hand, fruits having a long 

 growing season and maturing slowly, as the citrus fruits, are very 

 inactive physiologically. Peaches, plums, apples, pears, and grapes 

 are intermediate in this respect. 



(5) When plotted as logarithms, the values expressing the inten- 

 sity of respiration were found to lie principally along straight lines. A 



iled line drawn among the points therefore represented approxi- 

 mately the equation of the relation between respiratory activity and 

 temperature. By construction the form of this equation was log y 

 = log y + at, in which the constants y and a could be readily deter- 

 mined by inspection. The constant y varied for each kind of fruit. 

 The constant a varied slightly from one fruit to another and was 

 equal to 0.0376 ±0.00044, the value 0.00044 being the probable 

 error. (See p. 24 for definition of terms.) 



(6) The rate of respiration increased from 1.89 to 3.01 times, an 

 iverage of 2.376 times for each 10° rise in temperature for 49 sets of 



determinations with 40 different kinds of fruits. 



(7) The general equation expressing with fair exactness the effect 

 of temperature on the respiration of fruits is 



\ogy = logy Q +at, 



or, in the exponential form, 



y = y 10 at , 



where y is the rate of evolution of carbon dioxid expressed as milli- 

 grams of carbon dioxid per kilogram of fruit per hour at temperature 

 <°C.; y is the respiration rate at 0° C, and a = 0.0376 ±0.00044. 



39 



