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 + 



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. 



1. 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. 



