Quantitation of oxalates in corms and shoots of Colocasia esculenta (L.) Schott under drought conditions

Gouveia Carla S.S., Ganança José F.T., Lebot Vincent, Pinheiro de Carvalho Miguel A.A.. 2018. Quantitation of oxalates in corms and shoots of Colocasia esculenta (L.) Schott under drought conditions. Acta Physiologiae Plantarum, 40:214, 11 p.

Quartile : Q2, Sujet : PLANT SCIENCES

Résumé : Oxalate (calcium oxalate) accumulation in taro plants (Colocasia esculenta (L.) Schott) impacts their nutritional quality, producing acridity, causing lips, mouth and throat tissues swelling if consumed fresh. The oxalate content is related to photosynthesis, through the glycolate–glyoxylate oxidation pathway. The plant's photosynthetic rate usually increases in non-stressed conditions. Differences in photosynthetic rate are indirectly related to the chlorophyll content index. Protein accumulation and starch variation are also important traits to understand the taro oxalate synthesis caused by drought and how they affect corm quality. The purpose of this study was to quantitate oxalates in taro corms and shoots submitted to drought conditions and to evaluate how stress response can affect the nutritional quality of taro whole-plant. Seven taro genotypes from Madeira, Canaries and Pacific Community (SPC) collections were grown in greenhouse conditions and submitted to different watering regimes for drought tolerance screening. Corms and shoots were harvested and evaluated for oxalates (soluble, insoluble and total), chlorophyll content index (CCI), crude protein, starch, starch solubility in water and starch swelling power. All accessions had very high calcium oxalate content. Drought-tolerant genotypes showed good osmotic response by oxalate precipitation and mobilization through shoot to corm tissues, photosynthesis adaptation by increase of CCI, protein accumulation, and very low starch hydrolysis. Sensitive-drought genotypes showed less mobilization of calcium oxalate, decreased photosynthetic rate and protein synthesis, and slight increase of starch hydrolysis. Variation in taro oxalate content is consistent and significantly correlated with the photosynthetic rate, carbohydrate metabolism and protein synthesis.

Mots-clés Agrovoc : Colocasia esculenta, taro

Mots-clés géographiques Agrovoc : Madère, Canaries (îles), océan Pacifique

Mots-clés libres : Taro, Colocasia esculenta, Composition chimique, Sécheresse, Stress

Classification Agris : Q03 - Contamination et toxicologie alimentaires
F60 - Physiologie et biochimie végétale
F30 - Génétique et amélioration des plantes

Champ stratégique Cirad : Axe 1 (2014-2018) - Agriculture écologiquement intensive

Auteurs et affiliations

• Gouveia Carla S.S., University of Madeira (PRT) - auteur correspondant
• Ganança José F.T., University of Madeira (PRT)
• Lebot Vincent, CIRAD-BIOS-UMR AGAP (VUT)
• Pinheiro de Carvalho Miguel A.A., University of Madeira (PRT)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/589618/)

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