﻿578 Halsted : Starch Distribution 



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leguminosarmn Fk., were laid in the iodine solution along with 

 those from the roots near by and bearing the galls. The tissue of 

 the tubercles turned blue almost immediately, while the slices of 

 the roots themselves gave only the faintest indications of starch. 

 The tubercle has a layer of loose cellular tissue as a covering in- 

 side of which is the denser substance abounding in the bacterioids. 

 It is this covering that is gorged with starch and from it and reaching 

 in towards the center of the gall are irregular anastomosing broad 

 lines, also containing starch. 



Plants that are victims to parasitic fungi may possibly be in- 

 fluenced as if they were wounded. Richards, in his extended ex- 

 periments upon the respiration of wounded plants,* has concluded 

 that there is an increased respiration after an injury to plant 

 tissue, varying in amount and duration with the character of tissue 

 and extent of wound. "This increased respiration," to quote Dr. 

 Richards' words, " may be ascribed to an effort on the part of the 

 plant to recover from the injury by which the ordinary functions 

 of the plants are stimulated, thereby demanding and necessitating 

 an increased supply of oxygen." Bohn, f referred to by Richards, 

 " concludes there is no doubt that the cause of it (respiration) is 

 alone the irritation of the wound itself and not the increased op- 

 portunity for the action of the oxygen of the air." But Richards' 

 experiments and those of Stich, whose paper in Flora has not been 

 consulted, show "that the oxygen of the air plays an important 



ry." 



respi ratory 



Townsend| in his extensive studies states that slight injuries 

 accelerate the rate of growth and will continue for several days. 

 He states, " The change in the rate of growth of higher plants 

 under the influence of a single irritation begins gradually, reaches 

 its maximum in from twelve to ninety-six hours and gradually 

 diminishes until the normal rate is resumed." Also "The influ- 

 ence of an irritation due to cutting or other injury is capable of 

 acting t hrough a distance of several hundred millimeters. 



* Annals of Botany, 10 : 531-582. . D. 1896. 



t Ueber die Respiration der Kartoffel. Bot. Zeitung, 45 : 671. 1887 

 t The Correlation of Growth under the Influence of Injuries. Annah 

 " = 509-532. D. 1897. 



)f 



Botany 



