354 University of California Publications in Agricultural Sciences [Vol. 1 



the diy weight for plant I C 4 this weight would ])robal)ly have 

 been slightly greater than that of I U 4 (see table 2), making 

 the curves correspond to those for height. 



THE INFLUENCE OF THE CULTURE SOLUTION ON FLOWER 



PRODUCTION 



Our information concerning factors which may influence 

 flower formation is very incomplete. Vochting-^ has demon- 

 strated tliat light intensity is a factor in flower development in 

 Mimulus, and numerous other plant physiologists have found 

 that a more or less marked influence on flower formation could 

 be correlated with some external factor. The relation to the 

 formation of flowers of nutrient salts in the medium in which 

 growth takes place seems never to have been studied in any 

 thoroughgoing manner. Mobius"- found that certain Gramineae 

 flowered better on dry soil and on soil low in nutrient elements 

 than on soil rich in nutrients and where water supply was 

 abundant. Jost-'^ thinks that the fact that root pruning increases 

 flower production may be thus explained, since there is a lower- 

 ing of the absorptive capacity of the tree for inorganic salts. 

 There has been also a general opinion, which is not fully justified, 

 that any condition which will cause marked vegetative develop- 

 ment will retard flower production. The experiment herein re- 

 ported has presented an opportunity for a study of the influence 

 of the composition and concentration of the solution upon flower 

 production. 



In the plant used in this experiment the flowers fall soon 

 after opening, leaving a scar upon the inflorescence stock. -^ At 

 the end of the growing season the number of flowers produced 

 by each plant was determined by counting these scars (see table 

 2). The total number of flowers produced by each plant is shown 

 diagrammatically in figure 4. 



^1 Vochting, Jahrb. f. wiss. Bot., vol. 25, p. 149, 1893. 



22 Mobius, Beitr. z. Lehre v. d. Fortpfianzung d. Gewachse, Jena, 1897. 



23 Jost, Lectures on plant physiology, p. 364, 1907. 



21 Goodspeed and Ayres, Univ. Calif. Fubl. Bot., vol. 5, no. 9, 1916. 



