Minus nitrate in vivo nitrate reductase assay employed to determine the distribution of nitrate assimilation between the shoots (cotyledonary leaves) and foots of radish and cucumber indicated that because of the surplus of available nitrate in the radish roots and its deficiency in shoots, it was concluded that like pea, radish has the innate ability to “Capture” nitrate before it could be transferred into the xylem. It was the other way about in the case of cucumber for, nitrate was freely transported and made available for reduction in the shoots. The distribution of nitrate reductase activity between roots and shoots differed from species to species, and in addition to the availability of nitrate, it may also be attributed to the partitioning of carbohydrate between nitrate reduction and root growth.
