Sicher RC

Metabolites. 2015 Aug 5;5(3):443-54. doi: 10.3390/metabo5030443.

http://www.ncbi.nlm.nih.gov/pubmed/26251925

Abstract

Elevated growth temperatures are known to affect foliar organic acid concentrations in various plant species. In the current study, citrate, malate, malonate, fumarate and succinate decreased 40 to 80% in soybean leaflets when plants were grown continuously in controlled environment chambers at 36/28 compared to 28/20 °C. Temperature effects on the above mentioned organic acids were partially reversed three days after plants were transferred among optimal and supra-optimal growth temperatures. In addition, CO2 enrichment increased foliar malate, malonate and fumarate concentrations in the supra-optimal temperature treatment, thereby mitigating effects of high temperature on respiratory metabolism. Glycerate, which functions in the photorespiratory pathway, decreased in response to CO2 enrichment at both growth temperatures. The above findings suggested that diminished levels of organic acids in soybean leaflets upon exposure to high growth temperatures were attributable to metabolic impairment and to changes of photorespiratory flux. Leaf development rates differed among temperature and CO2 treatments, which affected foliar organic acid levels. Additionally, we report that large decreases of foliar organic acids in response to elevated growth temperatures were observed in legume species.

Figure 1. Effects of reciprocal changes of growth temperature on concentrations of organic acids in soybean leaflets grown with ambient CO₂ partial pressures. Plants were grown from seeds using continuous growth temperatures of 28/20 °C (●—●) or 36/28 °C (○—○). The first 21 or 22 DAS selected plants were transferred from the higher to lower (∆-----∆) or from the lower to higher (▼-----▼) growth treatment.