154 EXPERIMENT STATION. [Jan. 



MALNUTRITION. 



BY G. E. STONE. 



Malnutrition is a term referring to certain pathological con- 

 ditions in a plant which result from the improper use of plant 

 foods. It may occur from a lack of plant foods of any kind, or 

 starvation ; or it may result from an excess of some particular 

 plant food. 



An increasing number of troubles has been called to our 

 attention the past five or six years which have been found to be 

 typical cases of malnutrition, induced by an excess of some par- 

 ticular substance in the soil. By far the larger inindoer occur 

 in greenhouses, being found chiefly in the houses of growers 

 of limited skill and experience in handling greenhouse crops. 

 These troubles all originate from an injudicious use of com- 

 mercial fertilizers, or from applying certain manures to crops 

 in excess of what they can stand. 



The symptoms of malnutrition, as might be expected, are 

 more or less specific, the nature of the response depending not 

 only on the crop but also on the nature and amount of plant 

 food used. Identical stimuli may ])roduce different effects upon 

 different individuals, or plants remotely related to one another 

 may react similarly. The reaction of the plant to stimuli is 

 dependent more upon its individuality than upon the nature of 

 the stimulus which might give rise to any series of res})onses ; in 

 other words, the principal factor determining the nature of the 

 reaction is more a property of the individual than one associated 

 with the stimulus. 



In some cases an excess of fertilizers causes btirning of the 

 roots, which results in the death of the plant, but these are not 

 necessarily cases of malnutrition, since by the rapid and more 

 or less complete destrucfiou of the root system little or none of 

 the substances is absorbed. Burning and collapse of the root 



