Effect of Ethanol Toxicity on Enzyme Activity in Anaerobic Respiration in Plants
2014
Maricle, Brian R. | White, Shaley J. | Meraz, Alondra | Maforo, Nyasha G. | Biggs, Taylor N. | Martin, Nicole M. | Caudle, Keri L.
Ethanol, a metabolic toxin, is produced by plants during anaerobic fermentation. Traditionally, it was hypothesized wetland plants, which are tolerant of anaerobic conditions in sediments, might be those most tolerant of ethanol toxicity. Even though ethanol does not typically accumulate to toxic levels in field conditions, whether flooding tolerance in plants is related to tolerance of ethanol remains an open question. Therefore, we compared flood-tolerant and flood-sensitive species to assess susceptibility to ethanol exposure. Ten species of plants were compared; 4–10 replicate plants of each species were grown in flooded (anaerobic) and drained (aerobic) soil conditions in a greenhouse. Following seven days of treatment, roots were harvested and alcohol dehydrogenase (ADH) was extracted, a key enzyme in anaerobic fermentation. Effects of increasing ethanol concentrations were measured on activities of ADH. Root ADH activities increased in sensitive species with flooding. Increasing ethanol concentrations decreased ADH activity, with flood-sensitive species appearing to be most sensitive to ethanol. The flood-sensitive species Andropogon gerardii, Schizachyrium littorale, Phalaris arundinacea, and Tamarix ramosissima were impacted by flooding and ethanol to a greater extent compared to estuarine and flood-tolerant species Spartina alterniflora, Spartina patens, Solidago sempervirens, Juncus effusus, and Phragmites australis. The grass Distichlis spicata displayed intermediate flooding tolerance. These results indicate there is correlation between susceptibility to flooding and ethanol toxicity, suggesting tolerance to flooding might be related to ethanol tolerance in plants.
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