28 



Our conclusions, therefore, are not at variance with those of other 

 ■experimentors. Namely, that the single slioot plants produce the 

 largest amount of fruit when the amount of trellis space occupied 

 by them which is practically equivelant to ground space is taken into 

 consideration. Our experiments also agree with those of others in 

 respect to early maturity of fruit on pruned plants and the larger size 

 of such fruit. In other words, there is some gain in the maturity of 

 fruit and also a gain in the average size of the individual fruit by 

 pruning. 



EXPERIMENTS SHOWING THE EFFECTS OF MUTILA- 

 TION, OR CUTTING, ON GROWTH. 



The experiments in this series, which were made in a more detailed 

 manner than those already reported, show the influence which muti- 

 lation of various kinds has upon the growth of plants. They rep- 

 resent results that are typical of a \ery large number of experiments 

 made by us on various species of plants, including some of the simp- 

 ler and lower forms of organisms as well as the higher types of 

 plant life. 



The plants in all of these experiments were as evenly paired as 

 possible, and in the majority of cases daily measurements were made 

 previous to mutilating them in order to obtain plants of a uniform 

 rate of growth. Moreover, the conditions under which these plants 

 were grown were such that temperature, moisture and other modifying 

 factors did not exert any appreciable influence on the character of 

 the results. 

 Table X, Experiment showing the effects of cutting primary roots on 



the growth of stems (hypocotyls) of Helianthus annuus, L. 



i6 plants used, 8 normal and 8 cut. All but 3 centimeters 



of the primary roots were removed in the cut plants. 



Plants cultivated in sawdust. Growth of normal plants 



equals loo'y'r. 



.•\verage daily growth in millimeters. 

 234 56 



Normal 7.1 9.3 12.7 14.0 18.6 22.7 16.3 



Gut 3.7 7.3 9.7 1 1.7 18.0 20.3 16. 1 



Percentage } Daily growth 52^^ 78^/ 76^ 84''/ 97^/ Sg^jr gg^jr 



Cut to uncut j Total growth 82'/^ 

 Average height of hypocotyls before cutting 2.3 centimeters. 



