STUDIES IN POLLEN, WITH SPECIAL REFERENCE TO LONGEVITY 773 
determine whether there was any diminution. Sachsse’s method was 
used. Pollen was stored at room temperature in sealed bottles. The 
results are given in table 16: 
TABLE 16. CarsBoHyprats ANALYSES OF ANTIRRHINUM POLLEN 
Percentage of fresh 
substance 
Age Condition : 
Reducing Sucrose 
sugar 
Days Per cent Per cent 
()n.o og 615 6 6'0'S dle NS Se Gl eee nant eee PN ivie Reese ata oe: 0.40 7.20 
I oc cco dbbb do oS SSeS eee ee eee een AIVGies ee eee 0.55 6.80 
24) on Bid bic bie CICS SE a ee ee EYEE KG hk Ae cele 25 abe 3.90 1.20 
SIO, 4c 6 6 6 ood SRR OES eee eee eeree DD cadis trey eee 2.10 0.32 
These results show a perceptible decrease in the stored sugars as the 
age of pollen increases, this reserve probably having been used in respira- 
tion. As the dead pollen still contained a large amount of stored food, 
it is improbable that a lack of it had caused the mortality. 
Decrease of certain enzymes 
Since cane sugar is the chief storage carbohydrate, invertase would 
be one of the important enzymes present. Tests were therefore made 
of the activity of invertase as the age of the pollen increased. Weighed 
quantities (100 milligrams) of Antirrhinum pollen were placed in small 
bottles at room temperatures. At the intervals given in table 17, 
invertase was extracted and a determination of its activity was made. 
The method used was similar to the one recommended by Green (1894). 
The pollen (100 milligrams) was ground for several minutes in a mortar 
with a few drops of a 5-per-cent sodium-chloride solution. It was then 
diluted to 10 cubic centimeters and filtered. To 10 cubic centimeters 
of 5-per-cent cane-sugar solution was added 2 cubic centimeters of this 
extract. Digestion continued for twenty-four hours at 30° C. The 
results are given in table 17. 
These results indicate a marked decrease in the invertase content 
in dead pollen over that in live pollen. However, there is still some 
invertase present, 
