Figure 6. The relationship between leaf δ13C (‰) isotope and stem δ13C isotope (‰) for ‘Honeycrisp‘ apple trees on B.9, M.9, G.969, CG.4292, G.210, G.87, CG.5257, G.814, G.890 rootstocks (P = 0.05, r = 0.8914). The line indicates the best-fit adjusted non-linear regression for the combined data points.