Seasonal dynamics and punctuated carbon sink reduction suggest photosynthetic capacity of boreal silver birch is reduced by the accumulation of hexose
© 2024 The Authors. New Phytologist © 2024 New Phytologist Foundation.
| Veröffentlicht in: | The New phytologist. - 1979. - 243(2024), 3 vom: 10. Juli, Seite 894-908 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2024
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| Zugriff auf das übergeordnete Werk: | The New phytologist |
| Schlagworte: | Journal Article fructose hexose leaf gas exchange nonstructural carbohydrates photosynthetic capacity silver birch Hexoses Water 059QF0KO0R mehr... |
| Zusammenfassung: | © 2024 The Authors. New Phytologist © 2024 New Phytologist Foundation. The 'assimilates inhibition hypothesis' posits that accumulation of nonstructural carbohydrates (NSCs) in leaves reduces leaf net photosynthetic rate, thus internally regulating photosynthesis. Experimental work provides equivocal support mostly under controlled conditions without identifying a particular NSC as involved in the regulation. We combined 3-yr in situ leaf gas exchange observations (natural dynamics) in the upper crown of mature Betula pendula simultaneously with measurements of concentrations of sucrose, hexoses (glucose and fructose), and starch, and similar measurements during several one-day shoot girdling (perturbation dynamics). Leaf water potential and water and nitrogen content were measured to account for their possible contribution to photosynthesis regulation. Leaf photosynthetic capacity (A/Ci) was temporally negatively correlated with NSC accumulation under both natural and perturbation states. For developed leaves, leaf hexose concentration explained A/Ci variation better than environmental variables (temperature history and daylength); the opposite was observed for developing leaves. The weaker correlations between NSCs and A/Ci in developing leaves may reflect their strong internal sink strength for carbohydrates. By contrast, the strong decline in photosynthetic capacity with NSCs accumulation in mature leaves, observed most clearly with hexose, and even more tightly with its constituents, provides support for the role of assimilates in regulating photosynthesis under natural conditions |
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| Beschreibung: | Date Completed 04.07.2024 Date Revised 04.07.2024 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1469-8137 |
| DOI: | 10.1111/nph.19883 |