VI. OCCURRENCE IN NATURE 415 



VI. Occurrence in Nature 



H. J. ALMQUIST 



A. IN PLANTS 



Green leafy tissue is a rich natural source of the vitamin. One or two 

 per cent of commercially dehydrated alfalfa meal in the diet of the chick 

 meets normal requirements.^' - The tops of carrots are a good source, but 

 the roots contain little or no vitamin.^ The vitamin is more abundant in 

 peas sprouted in the light than in those sprouted in the dark, and the inner 

 leaves of the cabbage have about one-fourth the activity of the outer 

 leaves.* Other sources of the vitamin are spinach, kale, cauliflower, nettle, 

 and chestnut leaves.* The vitamin is present to some extent in tomato, 

 hempseed, seaweed,* and soybean oil.^ Berries of the European mountain 

 ash are reported to be a good source.^ 



Dam, Glavind, and Gabrielsen" have reviewed and extended earlier work 

 on the distribution of vitamin K in plants. Paits of plants which do not 

 normally form chlorophyll contain little vitamin K. Although conifers are 

 able to form chlorophyll in the dark, the amounts of chlorophyll and vita- 

 min K formed in the dark or light remain approximately proportional. 

 However, the yellow spotted leaf areas of certain plants contained as much 

 vitamin K as did the green areas. 



Leaves of various plants with markedly different natural green color 

 did not show a proportional amount of vitamin K activity by assay with 

 chicks. Neither was there any close relation to the amounts of carotene or 

 xanthophyll. Maize plants that were grown on an iron-deficient medium 

 showed marked deficiency of chlorophyll, xanthophyll, and carotene and 

 a reduction in vitamin K as compared to normal control plants. Natural 

 loss of chlorophyll, as in the fall yellowing of leaves, does not bring about 

 a corresponding change in vitamin K. Dam, Hjorth, and Kruse^ have also 

 shown that the vitamin K in the press juice of spinach leaves does not de- 

 crease on standing overnight and nearly all the vitamin i« present in the 

 chloroplasts. It seems evident, therefore, that any relation between the 

 concentrations of the chloroplast pigments and vitamin K in leaves is only 

 incidental to the general synthesis of all these substances in the leaves. It 



1 H. J. Almquist and E. L. R. Stokstad, /. Biol. Chem. Ill, 105 (1935). 



2 A. J. Quick, Am. J. Physiol. 118, 260 (1937). 



3 H. J. Almquist, Nature 140, 25 (1937). 



* H. Dam and J. Glavind, Biochem. J. 32, 485 (1938). 



5 H. J. Almquist and E. L. R. Stokstad, J. Nutrition 14, 235 (1937). 



« G. Y. Shinowara, J. C. DeLor, and J. W. Means, /. Lab. Clin. Med. 27, 897 (1942). 



"> H. Dam, J. Glavind, and E. K. Gabrielson, Acta Physiol. Scand. 13, 9 (1947). 



* H. Dam, E. Hjorth, and I. Kruse, Physiolocjia Plantarum 1, 379 (1948). 



