Resource integration is a widespread phenomenon in clonal plants that allows for potential translocation of carbon and water between interconnected ramets. To better understand the importance of this process in Chickasaw plum (Prunus angustifolia Marsh.), we severed the roots between interconnected ramets on the interior and periphery of clonal stands and left undisturbed control plots for comparison. Severing was done before the 2008 growing season on a study site was in northwestern Oklahoma (Woods Co.). To determine the effects of severing, we measured annual growth (heights and diameters). On five days during the 2008 growing season, we also measured net photosynthesis (Anet), stomatal conductance (gs), and intercellular CO2 concentration (Ci) using an infrared gas analyzer (Li-Cor 6400) as well as midday stem water potential (Ψ) using a pressure chamber and soil volumetric water content (VWC) using TDR.
Results/Conclusions
Severing had little or no effect on diameter (P = 0.32) or height growth (P = 0.08) Diameter growth for the severed and unsevered ramets was 4.9 and 3.2 mm while height growth was 1.6 and 1.9 cm, respectively. As would be expected, leaf gas exchange, VWC, and Ψ all varied during the growing season. However severing did not significantly affect these variables (P ≥ 0.18). Values for severed and unsevered ramets were 11.8 and 12.4 mol m-2 s-1 for Anet, 0.181 and 0.186 mol m-2 s-1 for gs, 257 and 252 μmol mol-1 for Ci, -1.57 and -1.55 MPa for Ψ, and 16.9 and 17.4 % for VWC. Though Chickasaw plum possesses persistent root connections between ramets there appeared to be minimal importance of water or carbon resource integration between interconnected ramets.
