TITLE:
Oxalato, the Ion that Hides: Intracellular Accumulation in an Aluminum Tolerant Rice Cultivar
AUTHORS:
Everaldo Zonta, Roberto Oscar Pereyra Rossiello, Juliano Bahiense Stafanato, Rosane Nora Castro, Rychard Denyan Pereira de Assis, Roberta Cristiane Ribeiro
KEYWORDS:
Oryza Sativa, Aluminum, Organic Acids, Oxalic Acid, Chromatographic Profile
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.17 No.5,
May
27,
2026
ABSTRACT: Organic acid exudation is one of the main mechanisms of aluminum (Al) tolerance in plants. The contribution of intracellular accumulation of these compounds, nevertheless, remains much less explored, especially in rice. This study examined data from experiments carried out with two upland rice cultivars that differ in their response to Al: Comum branco (tolerant) and Caiapó (sensitive). The data come from the experiment described in Zonta et al. The new finding is that oxalate had a ratio of 2.6, while citrate and malate are mainly exuded. Principal component analysis (PCA) also shows that oxalate is functionally independent from the other organic acids. None of this was reported in the original study. The work used chromatographic profiles and multivariate statistics to investigate the distribution pattern of oxalate between root cellular content and exudate when plants were exposed to Al, and to contrast this pattern with those of citrate and malate. In the tolerant cultivar, oxalate concentration in the cellular content increased strongly under Al stress, with rises of 128% at 4 days and 113% at 15 days (p