54 POMOLOGY 



remain unproductive of fruit." Jost ^ states, "It would ap- 

 pear that growth is an essential precedent of reproduction. 

 It is so, however, only in so far as growth is associated with 

 vigorous assimilation, for it is shown that the construction 

 of reproductive organs necessitates the previous accumu- 

 lation of a certain amount of nutritive materials, and these 

 must be all the more abundant the more complex the re- 

 productive organs are." 



Fruit-growers, especially, have assumed that there is abun- 

 dant evidence indicating that overbearing of trees results 

 in exhaustion of their "reserves" and, consequently, in alter- 

 nate or irregular bearing also, if indeed the trees are not 

 permanently incapacitated. It must also be recognized 

 that exhaustion may be concerned with very different clas- 

 ses of reserves and this makes it evident that the remedies 

 for unfruitfulness may vaiy greatly in practice. In general, 

 however, the formation of fruit-buds in abundance on the 

 young trees is preceded by a decrease of growth extension 

 and the accumulation of reserve food materials, and further- 

 more by a proper balance of them within the tissues of the 

 plant. Of the reserve materials that have been considered 

 to play a large part in the process are carbohydrates, nitro- 

 gen- and phosphorus-complexes, and fats, 



51. Carbohydrates, nitrogen-complexes, and moisture. — 

 It is, of course, understood that carl^ohydrates are products 

 of assimilation by green plants and that they constitute one 

 of the largest groups of organic compounds that are stored 

 as reserve foods. Of the carbohydrates, — starch, sucrose, 

 dextrose and levulose, — starch is by far the most abundant 

 form in which they are deposited as a reserve, although cane- 

 sugar or sucrose is found in considerable amounts, depend- 

 ing on the plant. It is probable also that hemicelluloses 

 and pentosans constitute an important part of the reserves 

 1 Jost, L., Ibid. p. 357. 



