STORAGE AND TRANSLOCATION 281 



first visible product of photosynthesis, appearing as small drops 

 In the protoplasm. Among the important plants which supply 

 large quantities of commercial oils are the castor bean, coconut, 

 corn, cotton, flax, mustard, olive, poppy, and peanut. In only 

 one of these plants, the olive, is the oil found in a part other than 

 the seed. 



Inulin is found as a reserve in the Dahlia, artichoke (Helianthus), 

 chicory (Cichorium) and many of the Composite, but it is also 

 present in other families such as the Violacese, Iridacese, Liliacese, 

 Amaryllidacese. As mentioned in Chapter XII, it bears the same 

 relation to levulose that starch does to glucose. 



Hemicelluloses, which occur in the seeds of the date palm, coffee, 

 peas, and beans, as well as in many other storage regions, have 

 generally been considered of minor importance as reserve foods, 

 but Murneek thinks they play an important part in the storage 

 reserves of fruit trees. While not so readily available as sugars or 

 starches, the hemicelluloses are much more easily hydrolyzed than 

 ordinary cellulose and so may be used in time of seed germination 

 or of leaf and flower formation (fruit trees) when especially heavy 

 demands are made upon the stored reserves. 



Time of Translocation. — The foods which are made in the 

 leaves must be moved to the places of storage, and those foods 

 which are stored must later be again translocated to the place 

 where they are ultimately to be used. Storage begins at differ- 

 ent seasons of the year, depending upon the plant and the character 

 of the season. Under normal seasonal conditions, the maple be- 

 gins to build up reserves as early as May, while the oak does not 

 commence till July and the Scotch pine till August or September. 

 Accumulation goes on until the end of the summer in the case of 

 the deciduous trees, or until late in the fall in the evergreens. If 

 the season is late, the beginning of the accumulation of reserves 

 is postponed an equal length of time; but if the season has been 

 favorable, the pith, rays, cortex, and wood parenchyma will con- 

 tain a large supply of foodstuffs — mostly fats and starch — by 

 the time the leaves fall. The rate of accumulation will depend 

 upon the rate of the manufacture of food and the rate of removal 

 of the translocation products at the storage terminus, just as in 

 an automobile factory the rate of movement of the finished prod- 

 uct varies with the rate of manufacture and the rate of removal 

 at the storage or warehouse end. 



