114 



MINERAL SALTS ABSORPTION IN PLANTS 



2-0 r 



E 



o 



Q. 



\_ 

 O 



1-5 



1-0 



■S 0-5 



100 



c 

 o 



o 



CO 



XI 



o 





50 



OL 



Time, days 



E 2 



28-v>ii-l933 



-[ 10 



(b) 



r" 



I 

 I 



r- 



o 



E 



12 

 Noon 



Time, 



12 



hr 



Fig. 39. Transpiration and salt absorption 



a. Rates of water ( ) and phosphate absorption (•— •) by a sugar 



cane plant during several days. Root temperature indicated thus (— ) (re- 

 drawn from Van den Honert, 1933); b. Rates of water ( ) phosphate 



( ) and nitrate ( ) absorption by a plant of Sanchezia nobilis during 36 hr 



(redrawn from Van den Honert, Hooymans and Volkers, 1955). 



absorption of salts in intact barley and Cucurbita plants was more 

 markedly affected by factors which influence respiration, for 

 example aeration and temperature, than by those affecting water 

 absorption, such as illumination and humidity. Plants which were 

 initially low in salts absorbed about the same amounts of potassium 

 and bromide ions in light and darkness, and at high and low 

 humidity, although the amounts of water absorbed under the 

 different conditions varied greatly (Table 9). Moreover, about an 



