Nucleic Acid Metabolism of Vicia faba during Germination and Growth

During the growth of Vicia faba seedlings in the absence of an external nitrogen supply, the cotyledons decreased rapidly in dry weight and nucleic acid content. In the developing shoot the dry weight increased rapidly for four weeks and then very slowly over the next two weeks growth; the nucleic acid content of the shoot increased to a maximum after 4 weeks growth and decreased in amount during the next 2 weeks. On the other hand the roots increased in both dry weight and nucleic acid content throughout the growth period, although they only accounted for a small proportion of the total dry weight and nucleic acid content of the plant. These changes during germination and growth are discussed in relation to those occurring during these developmental stages in other plants.