Genomic basis for stimulated respiration by plants growing under elevated carbon dioxide

Abstract

Photosynthetic and respiratory exchanges of CO2 by plants with the atmosphere are significantly larger than anthropogenic CO2 emissions, and these fluxes will change as growing conditions are altered by climate change. Understanding feedbacks in CO2 exchange is important to predicting future atmospheric [CO2] and climate change. At the tissue and plant scale, respiration is a key determinant of growth and yield. Although the stimulation of C 3 photosynthesis by growth at elevated [CO2] can be predicted with confidence, the nature of changes in respiration is less certain. This is largely because the mechanism of the respiratory response is insufficiently understood. Molecular, biochemical and physiological changes in the carbon metabolism of soybean in a free-air CO 2 enrichment experiment were investigated over 2 growing seasons. climate change ͉ elevated CO2 ͉ free air CO2 enrichment ͉ metabolic ͉ soybean T he rate at which atmospheric CO 2 concentration ([CO 2 ]) is rising and driving climate change is the net consequence of anthropogenic carbon emissions plus ecosystem processes that release or remove carbon from the atmosphere. Carbon emission to the atmosphere from fossil fuel burning, cement production and land use change has risen to Ϸ10 PgCy Ϫ1 (1). Dark respiration from plants in terrestrial ecosystems is a much larger flux, emitting 50-60 PgCy Ϫ1 (2). The change in plant respiration that will occur by the middle to end of this century in direct response to rising [CO 2 ] has long been of interest and uncertainty (3, 4). Changes in respiration will combine with the well characterized stimulation of C 3 photosynthesis by elevated [CO 2 ] to impact the net primary productivity of ecosystems and their capacity to act as sources or sinks of carbon. Key synthesis papers have variously concluded that elevated [CO 2 ] will cause plant respiration to increase as much as 11%, decrease as much as 18%, or not change (5-8). This uncertainty corresponds to an increase or decrease in carbon release to the atmosphere similar in size to current anthropogenic carbon emissions. The primary reason for uncertainty is that the mechanisms of plant respiratory responses to elevated [CO 2 ] have not been resolved (3,(5)(6)(7)(8). This knowledge gap also restricts our understanding at the tissue and whole-plant scales of how elevated [CO 2 ] impacts growth and crop yield. Our research tested the hypothesis that plants respond to the greater carbon supply resulting from long-term growth at elevated [CO 2 ] through acclimation for increased metabolic capacity and greater respiratory flux. Results and DiscussionThe mechanisms by which field-grown plants respond to growth at elevated [CO 2 ] were investigated in this study by combining genomic analysis with biochemical and physiological phenotyping of soybean in a free-air CO 2 enrichment (FACE) experiment. Soybean was grown over its entire lifecycle in 4 plots at ambient [CO 2 ] (Ϸ380 mol⅐mol Ϫ1 ) and 4 plots at elevated [CO 2 ] (Ϸ550 mol⅐mol Ϫ1 ). This model system featured: (i...

Role of internal atmosphere on fruit ripening and storability—a review

“…7. Interactions of some of the volatiles like; C 2 H 4 , O 2 , CO 2 , SA/MeSA, JAs and NO on various components of respiratory metabolism was reported by Millar and Day (1996), Fan et al (1997), Yang et al (1998), Ederli et al (2006), Leakey et al (2009) and Wang et al (2010). This shows that different volatiles and gases can affect the status of respiration which in turn is closely linked with the potential shelf-life of plant parts (including fruits) after their harvest (Kader 1987;Kader and Saltveit 2003b;Varoquaux and Ozdemir 2005;Paul and Srivastava 2006;Paul et al 2010b).…”

Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress

“…Similarly, large number of studies on genome-wide expression profiling of plants grown under high [CO 2 ] have been carried out Leakey et al, 2009;Cseke et al, 2009;Wei et al, 2013). Ribeiro et al (2013) showed that high [CO 2 ] promote plant growth via a complex transcriptional network.…”

Response of leaf dark respiration of winter wheat to changes in CO2 concentration and temperature

“…However, previous studies have focused mainly on the impact of changes in atmospheric CO 2 concentration (hereafter expressed as [CO 2 ]), moisture, and temperature on crop photosynthesis [2][3][4][5][6] and agricultural ecosystem soil respiration [7][8][9][10]. Studies on the response of crop respiration to changes in [CO 2 ], moisture and temperature are still inadequate [11,12]. This restricts accurate assessment of crop respiration and affects accurate simulation of product yield.…”

“…This restricts accurate assessment of crop respiration and affects accurate simulation of product yield. Although studies of the impacts of [CO 2 ] enrichment on respiration of soybean and rice have been carried out through experiments employing free-air carbon dioxide concentration enrichment (FACE) and open top chambers (OTC), the study results show great divergence [12][13][14][15] and quantitative evaluation of the relationships of dark respiration has not been established yet.…”