362 University of California Fublications in Aaricultural Sciences [Vol. 1 



greatest flower production occurred in group B, and plant 5 of 

 this group produced a larger number of flowers than any other 

 plant in any series. 



INJURY DUE TO EXCESS OR DEFICIENCY OF NUTRIENT SALTS 



The deficiency or excess of certain elements will cause injury 

 which is very characteristic. Gris as early as 1843 showed that 

 chlorosis was caused by a lack of iron in the nutrient solution. 

 Nitrogen starvation likewise has long been known to cause chlo- 

 rosis, a condition which may also result from an excess of soluble 



Decigrams. 

 Dry wt. of tops 



Cm. 



'^; K0SO4 



Fig. 10. — Graph showing the influence upon dry weiglit of tops of equal 

 quantities of K^SO^ in the different groups of series III. 



phosphate."'' Magnesium starvation results in injury to the 

 chlorophyll bodies, and in excess is harmful unless antagonized 

 by calcium.^'- Other physiological disturbances not so well estab- 

 lished as these mentioned have been considered to be associated 

 with a deficiency or excess of nutrient elements. 



The most marked indication of the fact that certain cultures 

 in this experiment did not furnish a normal medium for growth 

 was seen in the chlorosis which is so characteristic of plants 

 grown in solutions which are deficient in nitrogen. This type 

 of injury was uniformly present in all cultures containing 1 .0 g. 

 or less of NaNO.;, but was especially marked in series I, plants 

 1, 2, and 3, of all groups. It is not possible to draw a sharp 



2n Crone, Sitzungsber Neiderrhein. Ges. Nat.- und Heilk, Bonn, 1902, 

 pp. 167-173. 



3oLoew and May, U. S. Dept. Agric. Bur. Plant Tnd. Bull. 1, 1901. 



