40 



FATS, OILS. AND WAXES 



Le Clerc du Sablon also found the same relation between 

 oil and sugar to obtain during germination of rape, hemp, 

 poppy, almond, and walnut. 



Similar observations have been made by Green and Jack- 

 son,* who found that in the resting seed of Ricinus the most 

 abundant sugar is sucrose, which gives place to invert sugar in 

 the early stages of germination. Subsequently the sucrose 

 increases in amount, and occurs in quantities greater than the 

 invert sugar ; thus there is reason for supposing that the 

 sucrose is a temporary reserve food. 



The following table which summarizes the changes in the 

 sugar content is taken from Green and Jackson's paper : — 



Miller has found that in the sunflower, Helianthus annuus, 

 the amount of ether extract of the cotyledons diminishes 

 gradually from the beginning of germination, the most rapid 

 depletion occurring during the period between the first ap- 

 pearance of the seed-leaves above ground and the point of 

 full expansion. Also, the greatest increase in the hypocotyl 

 and roots coincides with the period of maximum depletion 

 from the seed-leaves. With regard to the sugar content, 

 Miller states that the resting embryo contains about 4 per cent 

 of sucrose, during germination there is a decrease, and this is 

 followed by a gradual increase until the seed-leaves begin to 

 unfold. Up to this stage the cotyledons contain only a non- 

 reducing sugar, but as the seed-leaves assume the functions 

 of foliage leaves a reducing sugar appears, and, in a short 

 time, is the only sugar present. In the hypocotyl and roots 



* Green and Jackson : " Proc. Roy. Soc, Lond.," B., 1906, 77, 69. 



