Injuries by Weather 317 



a temperature at or below freezing. See the discussion in 

 Cliapter VII (page 265). 



Harm may come to fruit-setting even though the tem- 

 perature does not touch the frost-point. Hedrick states 

 that "A temperature low enough to be harmful to blossoms 

 is usually associated with frost or rain; but a low tempera- 

 ture, even though it does not touch the frost-point, nor 

 accompany rain, is often disastrous to the setting of fruit. 

 The injurious effect is probably due to the prevention of 

 the growth of the pollen-tubes." 



THE EFFECT OF HAIN ON THE SETTING OF FRUIT 



It is well known that the weather conditions may pro- 

 foundly affect the fecundity of the flowers. In the forcing 

 of winter vegetables, for example, it is of the greatest 

 importance to keep the house dry and warm when poUi- 

 nation is to be effected, and better results — both in the 

 amount of pollen produced, and in the ease with which it 

 is discharged from the anthers — are commonly secured in 

 bright sunshine. (See, also, page 156.) It is probable that 

 if the flowers of fruit plants were to be kept constantly 

 wet, very little pollination would take place. It is likely 

 also, that dashing rains at blossoming time wash away 

 much of the pollen, but it is doubtful whether enough of 

 it is lost in such passing storms seriously to reduce the 

 crop. The most disastrous storms are probably those 

 milder ones of long duration, and which are accompanied 

 by a low temperature. Not only may such weather tend 

 to prevent the discharge of pollen, but it prohibits the 

 work of insects. 



It must be admitted that the above remarks are 

 largely inferences or results of general experience. We 



