Growth and maintenance respiration for individual plants in hierarchically structured canopies of Medicago sativa and Helianthus annuus : the contribution of current and old assimilates
• Respiratory costs of Medicago sativa and Helianthus annuus individuals growing in hierarchically structured stands in a controlled environment were analysed with regard to the daily rate of carbon (C) assimilation. • Net assimilation of new C (An , g C d-1 ) and respiration rates of new (Rnew ,...
| Publié dans: | The New phytologist. - 1984. - 164(2004), 2 vom: 25. Nov., Seite 305-316 |
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| Auteur principal: | |
| Autres auteurs: | , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2004
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| Accès à la collection: | The New phytologist |
| Sujets: | Journal Article 13C labelling Helianthus annuus Medicago sativa carbon use efficiency gas exchange growth and maintenance respiration hierarchical position relative growth rate |
| Résumé: | • Respiratory costs of Medicago sativa and Helianthus annuus individuals growing in hierarchically structured stands in a controlled environment were analysed with regard to the daily rate of carbon (C) assimilation. • Net assimilation of new C (An , g C d-1 ) and respiration rates of new (Rnew , g C d-1 ) and old C (Rold , g C d-1 ) were assessed by 13 CO2 labelling and gas exchange measurements. • Specific respiration rate of old C (rold , g C g-1 C d-1 ) decreased exponentially with increasing shoot biomass, but was not affected by the instantaneous relative growth rate (Δwi ). The growth coefficient g (Rnew : An ) was c. 0.32. In the most severely shaded subordinate plants, g was < 0.2, but low g stimulated rold . The contribution of Rnew to total respiraton (fR, new ) and the carbon use efficiency CUE (1 - R/(An +Rnew )) were c. 0.68 and 0.62 for Δwi > 0.1, respectively. For Δwi < 0.1, fR, new and CUE decreased with decreasing Δwi in both dominant and subordinate plants. • The results suggest that Rold was closely related to maintenance, whereas Rnew was primarily involved in growth |
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| Description: | Date Revised 20.04.2021 published: Print Citation Status PubMed-not-MEDLINE |
| ISSN: | 1469-8137 |
| DOI: | 10.1111/j.1469-8137.2004.01170.x |