Submitted to: International Horticultural Congress
Publication Type: Abstract only
Publication Acceptance Date: 5/20/2010
Publication Date: 8/22/2010
Citation: Glenn, D.M., Campostrini, E. 2010. Canopy sink-source partitioning influences root/soil respiration in apple. International Horticultural Congress. Interpretive Summary:
Technical Abstract: The root system of plants derives all its energy from photosynthate translocated from the canopy to the root system. Canopy manipulations that alter either the rate of canopy photosynthesis or the translocation of photosynthate are expected to alter dry matter partitioning to the root system. Field studies were conducted to evaluate the effect of trunk girdling (2008 and 2009) and summer pruning (2009) on root/soil respiration. In apple trees, within three days of girdling the trunk, the root/soil respiration rate increased more than 2X suggesting rapid root die-off and microbial decomposition of the dead root tissue that required 30 days to return to control levels. Summer pruning demonstrated a significant increase in root/soil respiration within two weeks of treatment, also suggesting root die-off and microbial decomposition of the tissue. These data demonstrate that common canopy cultural techniques may result in reduced root function due to reduced carbon partitioning to the root system that is necessary to maintain a given level of root biomass.