Dec, 1921] 
PATON — POLLEN AND POLLEN ENZYMES 
495 
pollen, 30 cc. of distilled water, and 2 cc. of toluol were placed in small 
stoppered flasks. For the control the pollen and water were heated in the 
autoclave. The suspensions were incubated at 37° C, and shaken fre- 
quently. The solutions were tested for sugar at 24-, 48-, and 96-hour 
intervals, and then allowed to stand for several weeks at room temperature 
to see if there would be complete destruction of the cellulose. In no case 
has this occurred, although several preparations have been kept for three 
months (see table 17). In testing for sugar the flasks were well shaken. 
Then the cellulose was allowed to settle out and 2 cc. of the clear liquid 
was transferred to a test tube and 10 cc. of Benedict's solution was added. 
All the tubes, both the unboiled and the boiled pollen controls, were then 
heated simultaneously in a boiling water bath until reduction was complete. 
If there was a striking difference in the amount of precipitate in the unboiled 
and in the control the quantitative test was made, but if no difference could 
be detected the precipitates were weighed as described on a previous page. 
Pollens were selected which did not all contain starch, so that the resulting 
gain in sugar did not come from this source. Yet the diminution in the 
amount of cellulose in the flasks was so slight that it is difficult to interpret 
results. 
Table 17 
Kinds of Pollen Unheated Pollen Autoclaved Pollen 
1. Apple + - 
2. Corn — — 
3. Daisy — — 
4. Dandelion — — 
5. Dock -f- - 
6. Elm - - 
7. Goldenrod — ' — 
8. Lily, Easter — — 
9. Lily, tiger — — 
10. Pine, Austrian + — 
11. Pine, white + — • 
12. Ragweed — — 
13. Rye + - 
14. Timothy -}- — 
15. Magnolia — — 
16. Maple, Norway — — 
Tests for Pectinase 
As has already been noted, special importance was attached to the 
possible occurrence of a pectinase as indicative that the pollen tube digests 
the inner lamella of pectin in the cell walls of the pistil. Three methods 
of testing for a pectinase were tried. 
I. Pistils of Easter lily were placed in a tube with distilled water and 
freshly ground pollen, and a second set were similarly treated with boiled 
pollen. After 24 hours the pistils were examined for alteration of texture. 
