Pea fruits from two crops were sampled at different times from flowering. Changes in the fresh weight, dry weight, starch, soluble carbohydrate, protein nitrogen, and soluble nitrogen in both seeds and hulls were followed in two seasons and related Jo the changes in cell volume in the seeds. In one season respiration rates and phosphate, pectin, and ascorbic acid contents were also investigated. The seeds gained more carbohydrate and nitrogen than was lost by the hulls. Starch and protein were synthesized rapidly by the seeds. The increase in starch content in the seeds was followed by a decrease in soluble carbohydrate content, after which the seed ceased to accumulate water. These metabolic changes are discussed in the light of recent biochemical knowledge, and in relation to more detailed biochemical investigations in progress.

SummaryThe ninhydrin-reacting compounds of the apple fruit have been studied during its development on the tree. The compounds present show little variation, but glutamine, conspicuous in very young and in over-mature apples, disappears at intermediate stages. The increase in soluble nitrogenous compounds occurring in over-mature apples left on the tree (Pearson and Robertson 1953) is confirmed qualitatively. An account is given of the chromatographic behaviour of several unidentified ninhydrin-reacting substances found in extracts of apple fruits, leaves, and stems.

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With I figure in the text) THE ACID AMIDES I N her 1929 review M. E. Robinson summarized the work of E.Schulze and of Pryanishnikov on the role of the acid amides, especially asparagine, in the plant's protein metabolism. Schulze held that asparagine was an essential stage in the synthesis of protein, while Pryanishnikov regarded it rather as a means of storing ammonia in a harmless form, its function thus being similar to that of urea in the animal, except that the latter is excreted and the nitrogen of the asparagine is still available for protein synthesis. The analogy of function between asparagine and urea has also been stressed by Murneek (1935) in a review of work on the metabolism of amides in the plant. The schemes he gives for their formation must now be regarded as unlikely, but this, of course, does not affect the functional analogy. Pryanishnikov's views on the position of asparagine in plant metabolism may be indicated in the following diagram, which is quoted from M. E. Robinson. Amino-acids >• Protein >.Amino-acids t i HNO, ^NH3-« Asparagine -< NHj COOH COOH COj CHNHj CO CHO COOH COOH