IMPORTANT MOVEMENTS OF PLANTS-II 



Bv JOH.N I. BlKCli 



CIRCUMNUTATION OF ROOTS 



"VT ( ) T only tlo the stems. It-avcs and stolons circuninutatc hut 

 ■^ ^ the rachcals. hyi)(>C()tyls and epicotyls of the seeding phmts 

 as well, e\en hefore they emerge from the ground. In all 

 gerniiating seed, the first change is the protrusion of the rad- 

 icle, which immediately hends downward and endeavors to 

 penetrate: the ground. There is a movement of the root tij) 

 which hores thru the soil and in this way makes a place for the 

 root. Then as the root grows and fills uj) the hole, the cells 

 hecome more numerous and exert a pressure on the side 

 sufficient to force the earth away, and in this way. due to the 

 close packing of the earth around the root, it is able to come 

 in direct contact with materials for growth- The movement 

 of the radicle, also guides it along the line of least resistance 

 as when tlie root happens to break obliquelv into cracks or into 

 liurrows made by earth worms or larvae. This movement, 

 combined with the sensitiveness of the tip to contact, is of 

 great inijjortance, for as the tip is always endeavoring to bend 

 to all .sides it will ])ress on all sides, and thus be able to dis- 

 crimate between the harder and softer abutting surfaces, thus 

 guiding the root. Consequentlv it will bend from harder soil 

 to the softer soil, materially aiding the plant. 



There is no structm-e in the plant more wonderful, as far 

 as its functions are concerned, than the tip of the radicle. If 

 this be lightly pressed or injured it transmits an influence to 



