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Publication
Quantitation of oxalates in corms and shoots of Colocasia esculenta (L.) Schott under drought conditions
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Advisor(s)
Abstract(s)
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.
Description
Keywords
Carbohydrate metabolism Chlorophyll content index Colocasia esculenta (L.) Schott Drought tolerance Photosynthesis Soluble and insoluble oxalates . Faculdade de Ciências da Vida
Citation
Gouveia, C. S., Ganança, J. F., Lebot, V., & de Carvalho, M. Â. P. (2018). Quantitation of oxalates in corms and shoots of Colocasia esculenta (L.) Schott under drought conditions. Acta Physiologiae Plantarum, 40(12), 1-11. https://doi.org/10.1007/s11738-018-2784-7
Publisher
Springer