SEEDLINGS 



109 



ledon on the second seedling for starch ; what has become 

 of it? Test sections of the root and stem of the same 

 seedling and see if any of the starch has gone into 

 them. 



147. Growth of the Plumule. — What part of the plumule 

 comes out of the ground first ? Is it straight or bent .'' 

 Open the outer sheath of a well-developed plumule with a 

 needle ; what do you find inside .■' Examine the plumule 

 of an older plant that has developed several leaves ; where 

 does the second one come from ? Look within that" for 

 the next one ; from where does the new leaf always seem 

 to proceed .■' Measure the internodes from day to day 

 and note their rate of growth in your book. 



148. Growth of the Root. —Examine the lower end of 

 the hypocotyl and find where the roots originate. Ob- 

 serve their tendency to spread out in 

 every direction, and even to develop 

 from the lower nodes of the hypo- 

 cotyl ; would you say that the roots 

 are an outgrowth from the stem, or 

 the stem from the root.' Mark off 

 a root into sections by moistening a 

 piece of sewing thread with indelible 

 ink and applying it to the surface 

 of the root at intervals of about one 

 millimeter (2V of an inch). Lay the 

 seedling on a moist bedding in a glass 

 jar, covered lightly to prevent evap- 

 oration, and watch to see in what part 

 of the root growth takes place. 



Notice the grains of sand or saw- 

 dust that cling to the rootlets of 

 plants grown in a bedding of that 

 kind. Examine with a lens and see if you can account for 

 their presence. Lay the root in water on a bit of glass, 

 hold up to the light and look for root hairs ; on what part 

 are they most abundant .'' 



242 243 



242, 243. — Seedling of 

 corn, marked to show re- 

 gion of growth : 242, eaiiy 

 stage of germination ; 243, 

 later stage. 



