Limits...
Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees.

Silva LC, Salamanca-Jimenez A, Doane TA, Horwath WR - Sci Rep (2015)

Bottom Line: Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration.Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees.Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.

View Article: PubMed Central - PubMed

Affiliation: Department of Land Air and Water Resources. University of California, Davis, CA-95616.

ABSTRACT
The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases ((13)CO2 and (15)NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the (13)CO2 pulse, assimilation and transport of the (15)NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.

No MeSH data available.


Related in: MedlinePlus

Total nitrogen concentration in leaves, stems and roots tissue, determined at the end of phase I.Horizontal lines within the boxes represent median values. The ends of the box represent the 75th and 25th quantiles and whiskers span the entire dataset including outliers. A full factorial analysis of main effects and interactions is presented in Supp Table 1. Letters show significant differences determined using Tukey HSD tests across treatments within each plant compartment (P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4543970&req=5

f2: Total nitrogen concentration in leaves, stems and roots tissue, determined at the end of phase I.Horizontal lines within the boxes represent median values. The ends of the box represent the 75th and 25th quantiles and whiskers span the entire dataset including outliers. A full factorial analysis of main effects and interactions is presented in Supp Table 1. Letters show significant differences determined using Tukey HSD tests across treatments within each plant compartment (P < 0.05).

Mentions: Differences in nitrogen content as a result of growth history provide further context for the observed differences in uptake of a pulse of isotopically labelled gas. As mentioned above, stimulation of growth by elevated CO2 was most clearly manifested as differences in aboveground biomass, maximized under NH4+ fertilization; at the same time, the foliar nitrogen concentrations of plants in this treatment (E-NH4+) were significantly greater than those of plants receiving NO3− (Fig. 2 and Supp Table 1). Plants grown under elevated CO2 generally had lower foliar nitrogen concentrations than those grown under ambient conditions, with the lowest levels of foliar nitrogen observed in the E-NO3− treatment (Fig. 2), which is consistent with a CO2-induced inhibition of NO3− assimilation into organic compounds shown in previous experiments8. Furthermore, differences in total aboveground biomass mirrored changes in nitrogen concentration in the plant tissue (Figs 1 and 2). This is diagnostic of nitrogen limitation637, an effect that was strongest under NO3− fertilization, despite the application of equal amounts of nitrogen during growth in all treatments.


Carbon dioxide level and form of soil nitrogen regulate assimilation of atmospheric ammonia in young trees.

Silva LC, Salamanca-Jimenez A, Doane TA, Horwath WR - Sci Rep (2015)

Total nitrogen concentration in leaves, stems and roots tissue, determined at the end of phase I.Horizontal lines within the boxes represent median values. The ends of the box represent the 75th and 25th quantiles and whiskers span the entire dataset including outliers. A full factorial analysis of main effects and interactions is presented in Supp Table 1. Letters show significant differences determined using Tukey HSD tests across treatments within each plant compartment (P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543970&req=5

f2: Total nitrogen concentration in leaves, stems and roots tissue, determined at the end of phase I.Horizontal lines within the boxes represent median values. The ends of the box represent the 75th and 25th quantiles and whiskers span the entire dataset including outliers. A full factorial analysis of main effects and interactions is presented in Supp Table 1. Letters show significant differences determined using Tukey HSD tests across treatments within each plant compartment (P < 0.05).
Mentions: Differences in nitrogen content as a result of growth history provide further context for the observed differences in uptake of a pulse of isotopically labelled gas. As mentioned above, stimulation of growth by elevated CO2 was most clearly manifested as differences in aboveground biomass, maximized under NH4+ fertilization; at the same time, the foliar nitrogen concentrations of plants in this treatment (E-NH4+) were significantly greater than those of plants receiving NO3− (Fig. 2 and Supp Table 1). Plants grown under elevated CO2 generally had lower foliar nitrogen concentrations than those grown under ambient conditions, with the lowest levels of foliar nitrogen observed in the E-NO3− treatment (Fig. 2), which is consistent with a CO2-induced inhibition of NO3− assimilation into organic compounds shown in previous experiments8. Furthermore, differences in total aboveground biomass mirrored changes in nitrogen concentration in the plant tissue (Figs 1 and 2). This is diagnostic of nitrogen limitation637, an effect that was strongest under NO3− fertilization, despite the application of equal amounts of nitrogen during growth in all treatments.

Bottom Line: Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration.Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees.Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.

View Article: PubMed Central - PubMed

Affiliation: Department of Land Air and Water Resources. University of California, Davis, CA-95616.

ABSTRACT
The influence of carbon dioxide (CO2) and soil fertility on the physiological performance of plants has been extensively studied, but their combined effect is notoriously difficult to predict. Using Coffea arabica as a model tree species, we observed an additive effect on growth, by which aboveground productivity was highest under elevated CO2 and ammonium fertilization, while nitrate fertilization favored greater belowground biomass allocation regardless of CO2 concentration. A pulse of labelled gases ((13)CO2 and (15)NH3) was administered to these trees as a means to determine the legacy effect of CO2 level and soil nitrogen form on foliar gas uptake and translocation. Surprisingly, trees with the largest aboveground biomass assimilated significantly less NH3 than the smaller trees. This was partly explained by declines in stomatal conductance in plants grown under elevated CO2. However, unlike the (13)CO2 pulse, assimilation and transport of the (15)NH3 pulse to shoots and roots varied as a function of interactions between stomatal conductance and direct plant response to the form of soil nitrogen, observed as differences in tissue nitrogen content and biomass allocation. Nitrogen form is therefore an intrinsic component of physiological responses to atmospheric change, including assimilation of gaseous nitrogen as influenced by plant growth history.

No MeSH data available.


Related in: MedlinePlus