Carbon and oxygen isotope composition of organic compounds in the phloem sap provides a short-term measure for stomatal conductance of European beech (Fagus sylvatica L.). - Keitel,C..; Adams,M..A..; Holst,T..; Matarakis,A..; Mayer,H..; Rennenberg,H..; Gessler,A.. (Plant, Cell and Environment, 2003)