Although succinic acid is known to be widely distributed in plant tissues there is only a limited amount of quantitative data on its occurrence. Studies which have been made of the changes in concentration of succinic acid(cas:110-15-6) during development of the tobacco plant indicate that it is to be regarded as one of the more active metabolites. In a previous study of the organic acids of the cotton plant it developed that 14 to 50%o of the total organic acids in various tissues were reported, as is customary, as "unidentified acids," i.e., acids other than citric, malic and oxalic.

This paper presents data on the concentration of succinic acid(cas:110-15-6) in the same or similar tissues. Materials and methods V was determined on new samples of cotton flowers and seed, otherwise the tissue samples were those used in the previous investigations for the measurement of citric, malic, oxalic, unidentified, and total organic acids. The succinic acid(cas:110-15-6) content of the tissues was determined by the method of PUCHER and VICKERY, using duplicate 1-gram, oven-dried samples. The determinations of citric, malic, oxalic, and total organic acids were by the methods of PUCHER et al. (5, 6). Results and discussion succinic acid(cas:110-15-6), table I, on the basis of dry weight, was found to be present in the cotton plant in successively lower concentrations in the leaves, bolls, flowers, seed kernels, petioles, stems, and roots. Although relatively large differences are shown in the concentration of succinic acid between some tissues, the leaves and roots for example, succinic acid(cas:110-15-6) was found to comprise only a small part of the dry weight of any of this plant material. Likewise, as shown in table I, its contribution to the total organic acidity of the several tissues approached 10%o only in the instances of seed and young bolls; in other tissues it constituted less than 5%o of the total organic acids. The data are of value in that they delimit the extent to which succinic acid can be turned to in efforts at accounting for the organic acids in the unidentified group.

The results obtained, table I, show that succinic acid(cas:110-15-6) constitutes an appreciable part of the previously unidentified acids occurring in the leaves (17%o), 13-day bolls (20%o) and mature seed kernels 1 Published with the approval of the Director of the Texas Agricultural Experiment Station as Technical Paper No. 1325.PLANT PHYSIOLOGY (29%o), but only a small part, even though possibly a highly important part, of these acids in the remaining plant parts examined. In general, the succinic acid content of the cotton plant does not appear to differ greatly, though slightly lower, from that reported for other plants that have been studied (1, 4, 7). In tissues of these other plants succinic acid has been found to vary from a trace to 0.8% of the dry weight. THE TEXAS AGRICULTURAL EXPERIMENT STATION COLLEGE STATION, TEXAS LITERATURE CITED