It^dex —222— Hoagland 



Montmorillonite, 16, 17 

 Mottle leaf disease, 35 



Neubauer method, 162 



Nitella cells, growth habit, plate 16 



Nitella cells, sap composition, 49, 50-53, 66 



Nitrate, absorption, 61, 120, 136 



Nitrate absorption, stimulation, respiration, 142 



Nitrate, effect of cropping on, 11 



Nitrate metabolism in plant, 136, 138 



Nitrate and organic acids, 137 



Nitrate a.s oxidizing agent, 138 



Nitrate reduction in plant, 59, 138 



Nitrate in soil solution, 10 



Nitrogen absorption and carbohydrate, 23 



Nitrogen, forms of, 114 



Nitrogen, losses from soil, 11 



Nitrogen metabolism, 139, 141-142 



Nutrient salts, proportions, 18, 19 



Nutrient solution, influence on composition of plants, 110 



Organic acid cycles, 140, 142, 143 



Organic acids, 22-23 



Organic acids, precursors, 139-141 



Organic acids and salt absorption, 128-136 



Organic acids in tomato, 137 



Organic acids in bufi'er systems, 129-132 



Organic acids and accumulation of salts, 132-136, 145 



Osmosis and water movement, 84 



Oxalacetic acid, 139, 140 



Oxalic acid in plants, 129, 135 



Oxidase activity, potato tuber, 146 



Oxidases, 30 



Pecan rosette, 35 



Permeability, 49, 50, 52, 62-64, 66, 68-70 



pH, soil, 16 



pH (see also Hydrogen-ion) 



pU, culture solutions, 18, 112-114; plate 23 



pH, sap, 134, 168 



Phosphate, hydrogen-ion relations, 114 



Phosphate, soil solution, 8 



Phosphorylated compounds, 146 



Potassium, availability in soil, 152-163; plates 27, 28 



Potassium, absorption by plants, 60, 61, 154-163 



Potassium, absorption from non-replaceable form, 158-160 



Potassium, absorption, relations to other bases, 164-166 



Potassium, absorption and ammonium ions, 165 



Potassium, absorption from bicarbonate, 132 



Potassium, absorption and nitrate ions, 165 



Potassium, adsorption by soil colloid, 157-158 



Potassium, balance of nutrients, 173 



Potassium, base exchange, 152-154 



