COS 4-8
Climatic stresses alter the type, localization, and remobilization of tannins in Quercus sp
Climate change and the associated abiotic stresses can alter the physiology of plants, which could potentially reflect in the chemical composition of the plant tissues. Environmental stresses not only influence the production of plant metabolites, but could also modify its resorption during the leaf senescence. The magnitude of this climatic regulation on production-resorption dynamics could be more evident in defense compounds that are mobile in plants. We studied the concentration of tannins, the water soluble polyphenolic compounds that are capable of precipitating proteins, in Quercus rubra at the Boston Area Climate Experiment (BACE) Waltham, MA. We measured the extractable and cell wall bound fraction of condensed and hydrolysable tannins in green and freshly-senesced leaves of Quercus that were exposed to a factorial combination of warming and precipitation treatments.
Results/Conclusions
Both condensed and hydrolysable tannins showed differences with altered temperature and precipitation treatments. Increased rainfall decreased condensed tannins in both the extractable and the bound fraction for both senesced and green tissue, while the warmer temperature had a marginal effect, slightly increasing the condensed tannins in the green tissue. The largest differences between green and senesced leaf tissues existed in the wet treatment, regardless of temperature, with senesced tissue showing higher concentrations of condensed tannins compared to green tissue. The hydrolysable tannins showed increased tannin amounts under the altered temperature and precipitation with ambient conditions (both in precipitation and temperature) yielding the lowest amounts of hydrolysable tannins for both green and senesced leaves. The results of this study indicate plant changes due climatic stresses at a more refined level and show that allocation to certain plant compounds alters with changing temperature and precipitation.