Hoagland 



— 78. 



Plant Nutrition 



between the upper and lower parts as affected by 

 conditions producing low or high transpiration, when 

 these are in marked contrast. 



It is helpful to describe still another experiment 

 with young barley plants which was simple in design 

 but involved a large amount of detailed work.* In 

 this experiment plants were grown for several weeks 



600 



400 



200 



Textfigurb 20. — Absorption and translocation of Br ions in 

 young barley plants under two environmental conditions, in con- 

 trolled chambers for maintaining desired temperature and 

 humidity. (Broyer and Hoagland). 



with three major differences in the manner of presen- 

 tation of inorganic nutrients to the plants: (a) nu- 

 trients were made available the entire 24 hours of 

 each day; (6) nutrients were available only 12 hours 

 out of 24, with illumination of the plants most or all 

 of the 12 hour period (depending on the time of year) ; 



♦This experiment was carried out by T. C. Broyer and 

 K. A. Grossenbacher at the writer's suggestion. 



