﻿iqi6] A DA MS — POLLEN GRAINS 135 



SERIES II 



May 8, 1913. — A single flower of Bismarck apple was used for 

 this set of experiments. It rained the whole day. Of the 20 

 stamens in the flower 13 had dehisced and all the pollen was washed 

 off by the rain. Of the remaining 7, 5 were kept in a corked bottle 

 over night and 2 were teased in 5 per cent and 10 per. cent sugar 

 solution respectively, and the cultures were placed outside in the 

 garden at 9:30 p.m., the temperature being 4? 5 C; the minimum 

 temperature during the night was 3? 5 C, and the temperature on 

 the following morning (May 9) at 8:50 a.m. was f C. The cul- 

 tures were examined at 9:30 a.m. A few of those in the 5 per cent 

 sugar solution had formed pollen tubes, but the majority had not 

 germinated. In the 10 per cent solution one pollen grain was 

 observed with a very short pollen tube. 



May 9, 1913. — Three of the 5 stamens kept over night were 

 teased in (a) water, (b) 5 per cent sugar, and (c) 10 per cent sugar 

 solution respectively, and the cultures were placed at 12:15 p.m. 

 in an incubator at a temperature of 20-2 1° C. The other two 

 stamens were teased in {d) 5 per cent and (e) 10 per cent sugar 

 solution respectively, and the cultures were placed on the window 

 ledge outside the laboratory at 12:15 P - M - Tne temperature out- 

 side the window at 3:00 p.m. was i2?5 C. The 5 cultures were 

 examined at 4: 15 p.m. on the same day, with the following results: 

 (a) some of the pollen grains had formed tubes of considerable 

 length; (b) several pollen grains had formed short pollen tubes; 

 (c) a few pollen grains had germinated and in some cases the pollen 

 tubes were of considerable length; (d) a number of pollen grains 

 had formed short pollen tubes; {e) only a very few had formed 

 pollen tubes of moderate length. 



SERIES III 



May 13, 1913. — Six cultures of pollen of Bramley's seedling 

 apple taken from the same anther were prepared, namely, (a) in 

 water, (b) 2.5, (c) 5, {d) 10, (e) 15, and (J) 20 cent sugar solu- 

 tion respectively. The pollen grains were collected on May 10, 

 1913, and were kept dry. The cultures were started at 4:30 p.m. 



