Submitted to: Physiologia Plantarium
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2014
Publication Date: 2/2/2015
Citation: Barnaby, J.Y., Fleisher, D.H., Reddy, V., Sicher Jr, R.C. 2015. Combined effects of CO2 enrichment, changes in diurnal light level and water stress on foliar metabolites of potato plants grown in naturally sunlit controlled environment chambers. Physiologia Plantarium. 153:243-252. Interpretive Summary: Due to climate change, agricultural production in the future will most likely be affected by prolonged episodes of drought. The potato crop is susceptible to drought because of its shallow root system. We investigated the combined effects of water stress, carbon dioxide enrichment, and light/dark effects on forty leaf components of potato plants grown in outdoor, controlled environment chambers. Over one half of the measured leaf components responded to drought and 20% were affected by all three environmental treatments. Results showed that water stress had a larger effect on plant metabolism than differences due to fluctuating daylight or to carbon dioxide enrichment. Also, we demonstrated that complex environmental effects on plant metabolism can be measured using modern techniques. These results provided important insights on the stress avoidance mechanisms of potato and suggested ways to enhance drought tolerance of this important crop. These findings should benefit breeders and ecologists working on the impact of environmental stress on plants.
Technical Abstract: Potato plants (Solanum tuberosum L. cv Kennebec) were grown in outdoor, naturally sunlit, soil-plant-atmosphere research (SPAR) chambers. Drought treatments were imposed at post-tuber initiation stage to assess water stress effects on leaf metabolites, and interactions with enriched CO2 concentration and diurnal changes in light. We observed that 23 of 40 metabolites were affected by drought when measured 11 d after initiating water stress treatments. Compounds that accumulated in response to drought were primarily hexoses, polyols, branched chain amino acids, and aromatic amino acids. Conversely, alanine, aspartate and several important organic acids decreased due to insufficient soil moisture. More than 70% and 50% of the metabolites in this study that were affected by drought responded to day/night changes in light levels or to ambient/elevated atmospheric CO2 treatments, respectively. In addition, over one-third of the water stress related metabolites in potato leaves were impacted by both CO2 and day/night changes in light levels.