New York Agricultural Experiment Station. 383 



In culture 10 which contained but 50 parts of the spray mixture 

 in 10,000, no more than one-quarter of the pollen germinated, and 

 that made even less vigorous gi'owth than was made in culture 

 9. 



In cult are 11 which contained but 2 parts of the spray mixture 

 in 10,000, and in culture 12 which contained but 1 part in 10,000, 

 the germination of the pollen and growth of pollen tubes 

 progi'essed fi'eely. 



Series II. — Culture media oontained oane sugar solution in water 

 and Bordeaux mixture. — In the 2 per ct. aqueous solution of cane 

 sugar alone the pollen from Ben Davis apple germinated freely 

 and the growth was vigorous and abundant. When 200 parts 

 in 10,000 of ordinary Bordeaux mixture were combined with this 

 sugar solution, culture 8, germination was almost wholly stopped. 

 But two pollen tubes started to grow and one of these soon 

 became disintegrated. When 500 parts Bordeaux mixture in 

 10,000 were used with a stronger (5 per ct.) sugar solution in 

 water no germination took place. 



Series III. — Culture media contained cane sugar solution in water 

 combined -with Bordeaux mixtw^ made from cJiemically pure 

 ingredients; also icith lime alone and with lime and green ar senile 

 of copper. — In this series blackberiy pollen Vvas used. Even in 

 the dilute sugar solution alone hardly half of the pollen grew. 

 Bordeaux mixture of the strength commonly used in spraying 

 orchaMs, mixture C, was used at full strength and also was 

 diluted with the weak sugar solution till it formed in the different 

 cultures respectfully 200 parts, 100 parts, 50 parts and 2 parts 

 in 10,000. In none of these media except the last named did 

 germination take place, in which case 28 per ct. of the pollen 

 grains in the culture started to germinate but before further 

 growth took place disintegration followed. It appears that the 

 blackberry pollen is even more sensitive to the poisons commonly 

 used in making spray mixtures than is apple pollen. The copper 

 arsenite and lime when not combined with Bordeaux mixture 

 prevented germination of the pollen. Even the lime alone seemed 



