POLLEN AND PISTILS OF APPLES 



395 



grams. About one-liailf c.c. of the various concentrations were 

 spread over the bottoms of watch glasses and after the pollen, 

 usually ranging from- 50 to 200 grains in amount, was intro- 

 duced, the watch glasses were sealed to prevent as far as possi- 

 ble changes in concentration resulting from evaporation. 



The membranes used were pieces of beef's bladder, and were 

 about 1 cm. square. After being soaked 15 or 20 minutes in dis- 

 tilled water and then dried between two blotters, the membranes 

 were put in watch glasses, pollen was spread on their surfaces 

 and the watch glasses were then sealed. 



In a mass of pollen from the same flower as well as from dif- 

 ferent flowers there was such a wide variation in the require- 

 ments for germination, th^at no conclusions could be drawn ex- 

 cept from the averages of a large number of tests. 



In table I are given the results obtained in two germination 

 tests to show the variations that occurred in the behavior of the 

 pollen in the cane sugar solutions. 



TABLE I. 

 VARIATION IN PERCENTAGES OF GERMINATION OF POLLEN 



IN WATER AND SUGAR SOLUTIONS AS SHOWN BY COM- 

 PARING THE RESULTS OF TWO TESTS. 



A temperature from 22° to 25° C. was found most favorable 

 for germination. The pollen of the five varieties was quite uni- 

 form in requirements and average results obtained in the germi- 

 nation tests of any one variety are representative of those ob- 

 tained for other varieties. 



The investigation first had to do with determining the behav- 

 ior of the poUen in distilled water and various concentrations of 

 cane sugar solutions at a temperature of 22° to 25° C, this being 

 the temperature found most favorable by other investigators. 

 Table II gives the results obtained with pollen of the Wealthy. 



