| Autor: |
Gesch, R. W, Vu, J. C. V, Boote, K. J, Hartwell Allen, L, Bowes, G |
| Předmět: |
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| Zdroj: |
New Phytologist; Apr2002, Vol. 154 Issue 1, p77-84, 8p, 2 Charts, 9 Graphs |
| Abstrakt: |
Summary • Photosynthetic acclimation of C3 plants to elevated atmospheric [CO2 ] is often attributed to soluble carbohydrate accumulation. We report the effects of modifying the carbohydrate source–sink balance on carbohydrate metabolism in mature leaves and partitioning in vegetative tissues of rice (Oryza sativa ). • Plants were grown under ambient atmospheric [CO2 ] in outdoor, sunlit, environment-controlled chambers. During late vegetative development treatments were changed to high or low [CO2 ]. • Within 1 d of changing to low [CO2 ], sucrose-phosphate synthase (SPS) activation was significantly reduced in mature leaves, while soluble invertase activity decreased. Plants switched to high [CO2 ] showed increases in SPS substrate-saturated and substrate-limited activities and a decline in invertase activity. The changes in SPS activity did not correlate with leaf sucrose pool size. By 9 d after the change from ambient to high [CO2 ], nonstructural carbohydrates in stems and leaf sheaths increased significantly; > 70% of this increase was due to sucrose accumulation, indicating that excess assimilate was being rapidly exported to vegetative sinks. • Results indicate that immediately following source–sink modification, regulatory adjustments in key enzymes controlling carbohydrate metabolism were linked to feedforward, rather than feedback, processes. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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