THE ACTION OF MANGANESE ON ROOTS 



hy H. BuRSTROM, Fil.Dr. 



Botanical Laboratory of the University, Lund, Sweden 



It is my intention to give only a very short account of some 

 recent results from experiments concerning the influence of man- 

 ganese on the growth behaviour of root tips. We knov^^, as a 

 matter of fact, very little about the specific influence of manganese 

 on roots as vi^ell as on the process of growth in general. 



Some years ago, I studied the connection between manganese 

 and the assimilation of nitrate in wheat roots and arrived at the 

 conclusion that manganese promotes, probably catalyses, the ni- 

 trate reduction in this organ. In this function it can be replaced 

 by iron to some extent only; all other cations, including iron, may, 

 under certain circumstances, inhibit manganese action. This 

 was assumed to depend upon some kind of competition of the 

 cations, in the system that promotes nitrate reduction. This 

 hypothetical function of manganese has been pardy confirmed by 

 the results of Noack's work on Chlorella, but it is also contradicted 

 by Steinberg's experiments with Asfergillus, and especially by 

 Mulder's investigations with various plants. These workers have 

 found a correlation between molybdenum and nitrate assimilation. 

 I only worked with isolated wheat roots, and our objects are so 

 dissimilar, that our results do not necessarily exclude each other. 

 It seems possible that the same function in different organs or 

 plants may be fulfilled by different elements, or that the metals 

 may replace each other to some extent. 



Another way of testing the action of manganese is to study its 

 effect on the morphological development of roots. The supply of 

 nitrogen and the reduction of nitrate are important growth factors; 

 on the other hand, there are, as far as I am aware, in the literature, 

 no records of direct effects of manganese on root development, nor 

 of any specific signs of manganese deficiency in roots at all. This 

 cannot be correct if manganese really plays some part in nitrate 



