340 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Plant Growth, The action of certain nutrient and non-nutrient 

 Bases on. By M. M. McCool (U.S.A. Exp. Stn., Cornell, Memoir 

 2, August 1913, pp. 113-216 ; 15 figs.). — This memoir is divided 

 into three parts. Part I. deals with the antitoxic action of certain 

 bases on plant growth ; Part II. deals with the toxicity of man- 

 ganese and the antidotal relations between this and other cations 

 with respect to green plants ; Part III. deals with the toxicity of 

 various cations. 



Part I. The plants used were Canada field peas and wheat. 

 The chief conclusions derived from the experiments were as follows : 

 Each of these substances, in the order given, is poisonous to seed- 

 lings : barium, strontium, ammonia, magnesium, sodium, potassium. 

 Although mutual antagonism results when cations are present to- 

 gether in solution as follows : Mg and Sr ; K and Sr ; Na and Sr, 

 Na and K ; Na and NH3 ; K and Ba ; Mg and Ba ; yet Calcium 

 is most effective in preventing toxic action. 



Protective action is not confined to the so-called essential nutrients. 

 Na, Sr, Ba possess this property also. 



The favourable results due to application of lime to soils is due 

 to antidotal relations. 



Part II. Similar plants were used. The general conclusions were 

 as under : Pure solutions of manganese salts are extremely poisonous 

 to seedlings. Toxicity is reduced by full nutrient solutions or in 

 soil cultures. The injurious action of Mn ion is shown in the upper 

 parts of the plants. Chlorosis of leaves is the first indication. 



Manganese is less injurious to plants grown in the dark than to 

 those grown in light. 



Ca, K, Na, Mg ions counteract the poisonous action of Mn. 

 Mutual antagonism exists between Mn and K ; Mn and Na ; Mn 

 and Mg. 



Part III. Ba,' Sr, NH3, Mg, Na, K (in order given) in pure 

 solutions are very toxic to seedHngs. This toxicity is reduced in 

 full nutrient solutions or soil cultures. 



Seedlings grown for ten days in distilled water, in tap water, or 

 in full nutrient solutions are far more resistant to any toxicant than 

 those immediately placed in toxic solutions. 



To each part there is appended a short bibhography. — A. B. 



Plum * Imperial Epicure.' By V. P. Hedrick (U.S.A. Exp. Stn., 

 Geneva, New York, Bull. 364). — A chance seedling found in 1870 in 

 the Valley of the Lot. Brought to the United States in 1883 and 

 first sold as ' Clairac Mammoth.' A promising market variety. 



E. A. Bd. 



Plum *Middleburgh.' By U. P. Hedrick (U.S.A. Exp. Stn., 

 Geneva, New York, Bull. 364).— A chance seedling found in the State 

 of New York some years ago. Considered to be one of the best in 

 cultivation. — E. A. Bd. 



