48 



MINERAL SALTS ABSORPTION IN PLANTS 



t 10 



=1, 6 



(Q) 



10 



20 



30 



40 



50 



Temperature, °C 



Time, 



hr 



Fig. 14. Temperature and salt absorption 

 a. Absorption of potassium ions by washed carrot tissue slices at different 

 temperatures in 30 min (O) and 2 hr (D) Sutcliffe (unpublished); b. The 

 time course of potassium absorption by washed carrot tissue slices at 

 2 °C (□) and 20 °C (O) Sutcliffe (unpublished). 



2. Light 



The effects of light on sak absorption are mainly indirect. 

 Visible light supplies energy for uptake in green plants through 

 photosynthesis, and, in addition, the gaseous exchange associated 

 with this process creates conditions favourable to active metabolism 

 and ion accumulation (see below). Light also has effects on the 



