236 THE PHYSIOLOGY OF PLANTS 



from the beginning that a very large number of flowers can 

 only be attained by the continuous functioning of a very large 

 amount of foliage. Assuming therefore that the soil is rich 

 in nutritive salts, as should always be the case in successful 

 horticulture, we must aim at producing as early a germination . 

 of the seeds as possible. Furthermore, the development of the 

 leaves must be helped on by quick-acting manures containing 

 potassium and nitrates, which should be applied as top-dressing. 

 But above all, there should be a copious supply of water to 

 aid in the elongation of the cells. These artificial aids should 

 gradually be decreased as the hot season approaches. The 

 more powerful effect of the sun and the decreasing amounts of 

 water will diminish and ultimately stop the production of new 

 leaves, and give the plant the opportunity of forming flowering 

 buds and help on the ripening of seeds and fruits. 



It depends entirely upon the specific peculiarities of the 

 plant and upon the aim of the gardener as to whether any 

 artificial aid should be resorted to after the flowering season. 

 If the production of, seeds is the chief aim of cultivation, it 

 seems best to leave the plants to themselves and to let the . 

 food material which has been formed by the leaves in the pre- 

 ceding vegetative period, but which has been stored up in the 

 stem, pass over into the ripening seeds. This passage froiii 

 the older to the younger portions of the plant takes place very 

 slowly, the leaves becoming gradually poorer in food matter 

 and turning yellow. Manuring during this period is directly 

 injurious. 



If, however, it is the aim of the horticulturist to produce 

 luscious and edible fruit, in which either . the ovary wall 

 (pericarp) or the receptacle is to become succulent and sweet, 

 it will be very beneficial to accelerate the natural processes, 

 by artificial means. For in this case it is not directly the 

 sexual organs which have to be nourished by the already formed 

 food material, but it is the growth of part of the vegetative 

 structure Of the plant which has to be promoted, and there- 

 fore those stimuli may be resorted to which tend to produce 

 foliage leaves. 



In the case of dessert fruits, the full development of the 

 succulent tissues, their tenderness, lusciousness, and sweetness 



