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Abstract Detail


Dong, Yanwen [1], Lapointe, Line [2], Gérant, Dominique [3].

Role of the alternative respiration in maintaining the source-sink balance in a spring ephemeral, Erythronium americanum.

The relationship between the activity of the sources and of the sinks within a plant is tightly regulated. When growth is sink limited, the plant must either reduce the activity of the sources or increase the use of C to maintain a balance between C fixation and C use. Many spring geophytes present better growth in cold than in warmer temperatures. Previous studies suggested that growth at low temperatures reduces the imbalance between the activity of the source and of the sink in these species, leading to longer leaf life duration and higher accumulation of biomass in the perennial organ. We posit that the alternative respiration is stimulated at low temperature in these species, either in the leaves as a way to reduce the amount of C exported to the bulb and/or in the bulb as a way to increase sink strength and maintain C import to the bulb for a longer period of time. We assessed the relative contribution of the aerobic respiration and of the non-phosphorylating alternative pathway as a function of growth temperature in both leaves and bulb of Erythronium americanum, a spring ephemeral. Plants were grown at three temperature regimes, 18/14°C, 12/8°C and 8/6°C (day/night), and the respiratory rates were measured at both growth temperature and a common temperature (12/8°C) in order to take into account the fact that respiration is known to increase with temperature and that the solubility of oxygen decreases with an increase in temperature. Both the activity and the capacity of the alternative pathway of respiration were enhanced in the leaves of plants grown at 8/6 °C throughout the growing season, and its participation reached 40% of the total respiratory rates, despite lower rate of photosynthesis than at warmer growing temperatures. In the bulb, the activity of the alternative pathway did not exhibit a consistent pattern in response to growth temperature. . It thus appears that C export to the bulb is strongly reduced at low temperature, through a combination of reduced photosynthetic rates and increased leaf respiratory rates. The alternative pathway of respiration would allow the plant to “burn” sugars, limiting feedback inhibition on photosynthesis which otherwise leads to early leaf senescence.

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Related Links:

1 - Université Laval, Département de biologie / Centre d'étude de la forêt, 1045, avenue de la Médecine, Pavillon Vachon, Bureau 3047-E, Québec, QC, G1V 0A6, Canada
2 - Universite Laval, Dept De Biologie, Pavillon Vachon, Québec, QC, G1V 0A6, Canada
3 - Université de Lorraine / INRA, Unite Mixte de Recherches 1137 Ecologie et Ecophysiologie Forestières, Faculté des Sciences et Techniques, entrée 1B, 4ème étage, Bd des Aiguillettes, VANDOEUVRE-Lès-NANCY, Lorraine, 54500, France

Erythronium americanum
source–sink relationship
alternative respiration.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PEP001
Abstract ID:163
Candidate for Awards:Physiological Section Best poster presentation,CSPB President's Award for Best Student Presentation

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