CHAPTER IV 



CHANGES OF COMPOSITION WITHIN THE PLANT 



The Manufacturing, Resting, and Spending Stages in a Plant's 

 Development. The Course of Nutrition and Migration in 

 the Growth of Wheat. The Ripening of the Grain. Storage 

 and Migration in Root Crops. Removal of Food Materials 

 from the Leaves of Trees as they Ripen. The Ripening of 

 Fruit. Effect of Soil and Climate upon the Composition and 

 Quality of the Crop. 



A REFERENCE has already been made to the fact that 

 the starch manufactured in the chlorophyll-containing 

 cells of the leaf is not allowed to remain there long, but 

 is transformed into soluble sugars by the action of 

 enzymes or ferments also present in the leaf, and is 

 then moved on to some other part of the plant, where 

 it is stored as sugar or as starch again until it is wanted. 

 It is now necessary to consider such processes rather 

 more generally from the point of view of the whole 

 economy of the plant, in which operations of manu- 

 facture, transport, storage, and remigration take place, 

 giving rise to the stages we call growth or resting or 

 ripening. In some plants the various operations we 

 have just enumerated can be seen very distinctly taking 

 place in succession; this is particularly the case with 

 bulbous plants, which have evolved the plan of laying 



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