Unravelling the mechanisms that improve photosynthetic performance of N2-fixing pea plants exposed to elevated [CO2]

Although the predicted enhanced photosynthetic rates of plants exposed to elevated [CO2] are expected to increase carbohydrate and plant growth, recent findings have shown a complex regulation of these processes. The aim of this study was to determine the effect of elevated [CO2] on pathways leading to the main forms of leaf C storage (starch) and export (sucrose) and the implications of this increased [CO2] on photosynthetic performance of exclusively N2 fixing plants. For this purpose, exclusively N2-fixing pea plants were exposed to elevated [CO2] (1000μmolmol-1 versus 360μmolmol-1 CO2). The data obtained highlighted that plants exposed to elevated [CO2] were capable of maintaining hexose levels (involved in Rubisco down regulation) at control levels with the consequent avoidance of photosynthetic acclimation. More specifically, in plants exposed to elevated [CO2] there was an increase in the activity of pathways involved in the main forms of leaf C storage (starch) and export (sucrose). Furthermore, the study highlighted that although starch content increased by up to 40% under elevated [CO2], there was also an increase in the proteins and compounds involved in starch degradation. Such a finding, together with an increase in the activity of proteins involved in sucrose synthesis revealed that these plants up-regulated the sucrose synthesis pathway in order to meet the large nodule photoassimilate requirements. As a consequence, the study highlighted the relevance of controlling the activity of pathways that determine leaf cellular carbohydrate availability and how this is linked with C-demanding organs such as nodules. © 2013 The Authors.

Bibliographic Details

Main Authors:	Aranjuelo, Iker, Cabrerizo, Pablo M., Aparicio-Tejo, Pedro María, Arrese-Igor, César
Format:	artículo biblioteca
Published:	Elsevier 2013
Subjects:	Elevated [CO2], Nodule, Sucrose, Photoassimilates, Starch, Pea,
Online Access:	http://hdl.handle.net/10261/97682
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