Abstract
The gas exchange of an oak stand in the southeastern forest steppe was examined under variable moisture availability and ambient temperature. For several years the CO2 exchange was measured concurrently on leafy shoots and nonphotosynthesizing organs (trunks, branches, and roots) of oak trees (Quercus robur L.). The root respiration was found to decrease upon moisture limitation. The trunk respiration was promoted by the increase in moisture deficiency until the predawn leaf water potential (PLWP) reduced to −1.5 MPa, and respiration declined gradually upon further reduction in moisture availability. The proportion between net and gross primary productivities (NPP/GPP) also depended on moisture availability. The NPP/GPP ratio was 0.49 under optimal conditions at PLWP of −0.5 MPa, but it approached zero when PLWP lowered to −1.5 MPa. Upon drought conditions, which are typical of southeastern steppe in the second half of summer, the oak stand lost its CO2 sink capacity and became the CO2 source.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
