262 



ORGANIC IRON COMPOUNDS IN PLANTS. 



fungus grown on a substratum poor in iron like rice (o.ooi% 

 Fe 3 0 3 ) store up so much iron in the spores 



Since the question whether iron forms a regular constituent 

 of nucleins is of considerable importance, I have made some 

 further investigations with vegetable materials. My attention 

 was first drawn to the richness in iron of the seed of Polygonum 

 tinctorium, and this has led me to analyse more fully the ashes 

 of the seeds and leaves of two indigo plants. 



Polygonum tinctorium Indigofera tinctoria 

 Seeds. Leaves. Seed;. Leaves. 



In 100 parts of dry matter ; 



Crude ash 



2.84 



15-5 



4.0 



4-3 



100 parts of ash. 











Si0 2 



o.35 



1-75 



3-i 



6.25 



SO, 



4.10 



477 



2.4 



3-8o 



p 2 o 5 



41. 1 



4-13 



34-2 



5.50 



K 3 0 



21.5 



21.40 



18.7 



17.80 



Na 2 0 



2.4 



6.00 



4.2 



2.00 



Fe 2 0 :i 



I 2. 1 



3-n 



12.0 



4.8 



CaO 



5-i 



39.10 



1 1 .0 



37-o 



MgO 



15.2 



12.30 



9.9 



6.4 



Total 



101.85 



S3.56 



95-5Q 



80.55 



We see that about 12% of the ashes, corresponding to 

 °-S4% °f the ^ r y matter, of the seeds consists of Fe 2 0 3 . 

 Similar results were obtained with other samples. Such a high 

 percentage of iron content in seeds has to my knowledge not 

 yet been observed. On looking through Wolffs tables, I found 

 that of the twenty two species of seeds examined, the richest 

 in iron contains only 2.5% in the ash and 0.08^ in the dry 

 matter. Occasionally plants absorb by accident unnecessary 

 substances from the soil and deposit them in the leaves and 

 stems, but this can hardly be the case with the seeds. 



In the following pages several experiments to isolate the 

 iron compounds from the seeds 1 are described. 



(1). Seeds of Polygonum tinctorium were dried and finely 

 pulverized, and treated with ether, absolute alcohol and water. 

 These Extracts contained no iron. Further the water extract 



1 All the materials used in this investigation were carefully tested for traces of iron 

 and were found free of them. 



