74 



SOILS AND PLANT LIFE 



cotyledons, out of the ground, carefully cut them away 

 from all the plants in one of the rows, so that these plants 

 can draw no more food from their cotyledons. 

 Keep all the plants properly watered, and measure the 



height every other day. Ar- 

 range your record in the form 

 of a table. 



Conclusions. — How did the 

 loss of the endosperm, or re- 

 serve food, affect the amount 

 of growth that the young 

 corn plants were able to make ? 

 How did the loss of the cotyle- 

 dons, or reserve food, affect 

 the growth of the beans ? Com- 

 pare the little plant, robbed 

 of its supply of food, with a 

 young animal which is poorly 

 fed. A fanning mill removes 

 the Ught small seeds from the 

 grain which we expect to sow. 

 Why does wheat which has 

 been run through a fanning 

 mill produce a stronger, more 

 vigorous growth of young 

 plants than wheat which has 

 Why do we usually remove the 



Fig. 23. — Effect of robbing 

 the plant of its stored food. 

 The cotyledons have been re- 

 moved from the seed of the 

 smaller plant. 



not been so treated? 



kernels from the tip of a seed ear of corn ? 



52. Direction of Growth. — A seed uses its reserve food 

 as the embryo develops into a larger plant. The plumule 

 always grows upward toward the light and the developing 

 root always grows toward the earth. Why this is true 

 remains a mystery. The effort, which either of these 



