CHAPTER IV 

 PHYSIOLOGY OF CORN PLANT 



Plant physiology deals with the activities and functions 

 of the physical parts of the plant. Not all parts of a 

 plant have a present important function. Certain parts 

 may be regarded as rudiments left in the process of evo- 

 lutionary change, and they may even be detrimental. In 

 other cases, certain parts may be regarded as only chance 

 variations of no value from an economic view point. It 

 is therefore important to make a careful analysis of plants, 

 to determine the function of each part, which parts have 

 an important function, and how the proper activities of 

 the plant are favored or hindered. 



27. Living plants. — One of the distinctive characters of 

 living plants as compared with dead material is the fact 

 that many forces of nature may act as a " stimulus " and 

 get a response entirely at variance with the usual result. 

 This is well stated in Strasburger ^ as follows : — 



"The free end of a horizontally extended flexible rod bends 

 downwards merely by its own weight. The same result will 

 follow if any part of a dead plant, such as a dry stem, be substi- 

 tuted for the rod. But if a living, growing stem be used in the 

 experiment, then the action of gravity will manifest itself in a 

 manner altogether at variance with its ordinary operation. 

 That part of the stem which is still in a state of growth will 

 ultimately curve upwards, and by its own activity assume an up- 



1 Strasburgeh, Noll, Schenk, and Kaesten. (1908.) Textbook 

 of Botany, p. 173. 



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