THE POLLINATION AND SETTING OF FRUIT BLOSSOMS. 24^ 



Temperatures a little below freezing point were found not to be 

 injurious to the pollen of apple, pear, and plum, though in the case of 

 the cherry and the peach about one-half of the pollen failed to ger- 

 minate after exposure to slight frost. 



The pistils of .apple, pear, plum, and cherry prove more susceptible 

 to low temperature than does the pollen; so that a severe frost will 

 kill the pistil, while it may not injure the pollen to any degree. 



It is often thought that the juice of the stigma becomes diluted and 

 washed off during heavy and prolonged rains. Observations appear 

 to show, however, that the stigma is not seriously injured by rain, 

 though prolonged rain prevents the proper dispersion of pollen during 

 the period of receptivity of the stigma, which lasts only for a few days. 



Comparing pollen of apple from a long-neglected orchard with one 

 well cultivated, it was found that pollen of the former lacked plump- 

 ness, regularity, and size, as compared with pollen from the other 

 orchard, and the length of time the pollen grains took to germinate 

 indicated a lower state of vitality. The size of the flowers in the 

 neglected orchard was much smaller, and the stamens and pistils were 

 dv/arfed and deformed in many cases. 



Apple pollen was found to germinate after six months when kept 

 in a dry place at a temperature of between 50° and 65° Fahr. The 

 length of time that plum pollen retained vitality was less, but, 

 generally, it would seem that pollen can be safely transported and 

 kept for some time without any very noticeable effect upon its 

 germination. 



Under favourable conditions it was found to take from 9 to 32 

 hours for the pollen tube of apples, plums, and cherries to reach the 

 ovary when placed on the stigma or in germinating medium. 



Cherry pollen required a little over twelve hours. 



Under natural conditions the time would be somewhat greater, but 

 two or three bright, warm days at the time of full-bloom is sufficient 

 for the setting of the fruit. 



These trials show that the danger period from frost is compara- 

 tively short, and account for the fact that often a frost during full- 

 bloom apparently does very little damage, while at other times a similar 

 frost may completely kill the essential parts of the flower. 



Summary and Suggestions for Experiments on Pollination of Fruits. 



It seems as if in the open field or garden strawberries are pollinated 

 by the movement of the air. Easpberries and loganberries need insect 

 pollination. The raspberry is more dependent on insect pollination 

 than the loganberry. Hive bees are very fond of raspberry blossoms, 

 and even more so of those of loganberry. In gooseberries and currants 

 it is of the utmost importance to have plenty of hive or bumble bees 

 near, as no fruit is set without them. They are also a necessity in the 

 case of pear, apple, cherry, and plum. 



As to pollination experiments on pear, apple, cherry, and plum, it 

 seems to me it would be advantageous to test in, say, the ten chief 



