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Recovery after defoliation in Eucalyptus globulus saplings: respiration and growth
journal contribution
posted on 2023-05-18, 17:41 authored by Alieta EylesAlieta Eyles, Pinkard, EA, O'Grady, AP, Stephen CorkreyStephen Corkrey, Christopher BeadleChristopher Beadle, Caroline MohammedCaroline MohammedDespite the importance of respiration in the overall carbon balance of plants, recovery after defoliation and debudding has been largely related to changes in carbon uptake; the significance of respiration has received much less attention. Growth, biomass and leaf-level carbon balance (both photosynthesis and dark respiration at night) responses of young Eucalyptus globulus potted-saplings to debudding (B), partial defoliation (D) and combined B&D treatments were assessed over a 12-week recovery period. Light-saturated photosynthetic rates (A1500) were asynchronous with night respiration rates (Rdark) throughout the course of the experiment; 5 weeks after defoliation, significant increases in A1500 were accompanied by concomitant increases in Rdark in the B&D and B and D treatments. By week 8, while A1500 returned to control values, Rdark had increased, particularly in the B&D treatment. Saplings in the B and D treatments showed full recovery with growth, biomass and leaf area being similar to control saplings by week 12. In contrast, saplings in the B&D treatment appeared unable to compensate for the combined removal of all buds and 35% leaf area as evidenced by slowed height increments and reductions in total biomass of >30%. Simple modelling of whole-plant net CO2 uptake showed that saplings in the B&D treatment fixed 20% less CO2 than the other treatments at week 12, suggesting that recovery following this treatment and the D treatment was dependent on changes in total leaf area development and whole-tree assimilation rather than differences in assimilation or respiration per unit foliage area. Increased biomass allocation to bud in weeks 5 and 8 suggested that the pattern of refoliation after defoliation and debudding was related to changes in tree architecture from the release of latent buds.
History
Publication title
Trees: structure and functionVolume
30Issue
5Pagination
1543-1555ISSN
0931-1890Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
SpringerPlace of publication
GermanyRights statement
© 2016 Springer-VerlagRepository Status
- Restricted