Abstract
Laboratory studies indicate that plant respiratory efficiency may decrease in response to low nutrient availability due to increased partitioning of electrons to the energy-wasteful alternative oxidase (AOX); however, field confirmation of this hypothesis is lacking. We therefore investigated plant respiratory changes associated with succession and retrogression in soils aged from 10 to 120 000 years along the Franz Josef soil chronosequence, New Zealand. Respiration rates and electron partitioning were determined based on oxygen isotopic fractionation. Leaf structural traits, foliar nutrient status, carbohydrates and species composition were measured as explanatory variables. Although soil nutrient levels and species composition varied by site along the chronosequence, foliar respiration across all sites and species corresponded strongly with leaf nitrogen concentration (r(2) = 0.8). In contrast, electron partitioning declined with increasing nitrogen/phosphorus (r(2) = 0.23) and AOX activity correlated with phosphorus (r(2) = 0.64). Independently, total respiration was further associated with foliar Cu, possibly linked to its effect on AOX. Independent control of AOX and cytochrome pathway activities is also discussed. These responses of plant terminal respiratory oxidases - and therefore respiratory carbon efficiency - to multiple nutrient deficiencies demonstrate that modulation of respiratory metabolism may play an important role in plant responses to nutrient gradients.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.