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Effects of elevated atmospheric CO2 concentrations, clipping regimen and differential day/night atmospheric warming on tissue nitrogen concentrations of a perennial pasture grass.

Volder A, Gifford RM, Evans JR - AoB Plants (2015)

Bottom Line: Both warming treatments increased leaf N concentrations under ambient CO2 concentrations, but did not significantly alter leaf N concentrations under elevated CO2 concentrations.Nitrogen resorption from leaves was decreased under elevated CO2 conditions as well as by more frequent clipping.Overall, the effects of CO2, warming and clipping treatments on aboveground tissue N concentrations were much greater than on belowground tissue.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California - Davis, Davis, CA, USA avolder@ucdavis.edu.

No MeSH data available.


Effect of warming treatment, Amb = ambient temperature, HN = +2.2/+4.0 °C (day/night warming), CW = +3.0 °C continuous warming and atmospheric CO2 concentration (ambient, 405 p.p.m., and elevated, 756 p.p.m.) on (A) green leaf N concentration and (B) green leaf C : N ratio. Data presented are least square means and SEM averaged across harvests and clipping frequencies. Different letters indicate statistically significant differences at P <0.05 using Student's t LSD test.
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PLV094F2: Effect of warming treatment, Amb = ambient temperature, HN = +2.2/+4.0 °C (day/night warming), CW = +3.0 °C continuous warming and atmospheric CO2 concentration (ambient, 405 p.p.m., and elevated, 756 p.p.m.) on (A) green leaf N concentration and (B) green leaf C : N ratio. Data presented are least square means and SEM averaged across harvests and clipping frequencies. Different letters indicate statistically significant differences at P <0.05 using Student's t LSD test.

Mentions: Warming was without any overall effect on green leaf N concentration when averaged across all the other treatments and harvest times (Table 1). However, there were strong interactive effects of warming with CO2 and harvest period. Averaged across CO2 treatments, both warming treatments greatly increased leaf N concentration in the second summer (Pharvest × warm < 0.001, December–March 2003, Fig. 1C and D). In contrast, continuous warming decreased leaf N concentration in comparison with ambient temperatures in the winter (May–September 2002, Fig. 1C). When averaged across all dates and clipping frequencies, warming significantly increased leaf N concentrations under ambient CO2, but under elevated CO2, leaf N concentration was not affected by warming (Fig. 2A). The negative effect of increased atmospheric CO2 concentration on leaf N concentration was substantially enhanced by both warming treatments, from 7.6 % decrease under ambient temperature to 17.5 and 21.4 % decrease under continuous and high night-time warming .Figure 2.


Effects of elevated atmospheric CO2 concentrations, clipping regimen and differential day/night atmospheric warming on tissue nitrogen concentrations of a perennial pasture grass.

Volder A, Gifford RM, Evans JR - AoB Plants (2015)

Effect of warming treatment, Amb = ambient temperature, HN = +2.2/+4.0 °C (day/night warming), CW = +3.0 °C continuous warming and atmospheric CO2 concentration (ambient, 405 p.p.m., and elevated, 756 p.p.m.) on (A) green leaf N concentration and (B) green leaf C : N ratio. Data presented are least square means and SEM averaged across harvests and clipping frequencies. Different letters indicate statistically significant differences at P <0.05 using Student's t LSD test.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591745&req=5

PLV094F2: Effect of warming treatment, Amb = ambient temperature, HN = +2.2/+4.0 °C (day/night warming), CW = +3.0 °C continuous warming and atmospheric CO2 concentration (ambient, 405 p.p.m., and elevated, 756 p.p.m.) on (A) green leaf N concentration and (B) green leaf C : N ratio. Data presented are least square means and SEM averaged across harvests and clipping frequencies. Different letters indicate statistically significant differences at P <0.05 using Student's t LSD test.
Mentions: Warming was without any overall effect on green leaf N concentration when averaged across all the other treatments and harvest times (Table 1). However, there were strong interactive effects of warming with CO2 and harvest period. Averaged across CO2 treatments, both warming treatments greatly increased leaf N concentration in the second summer (Pharvest × warm < 0.001, December–March 2003, Fig. 1C and D). In contrast, continuous warming decreased leaf N concentration in comparison with ambient temperatures in the winter (May–September 2002, Fig. 1C). When averaged across all dates and clipping frequencies, warming significantly increased leaf N concentrations under ambient CO2, but under elevated CO2, leaf N concentration was not affected by warming (Fig. 2A). The negative effect of increased atmospheric CO2 concentration on leaf N concentration was substantially enhanced by both warming treatments, from 7.6 % decrease under ambient temperature to 17.5 and 21.4 % decrease under continuous and high night-time warming .Figure 2.

Bottom Line: Both warming treatments increased leaf N concentrations under ambient CO2 concentrations, but did not significantly alter leaf N concentrations under elevated CO2 concentrations.Nitrogen resorption from leaves was decreased under elevated CO2 conditions as well as by more frequent clipping.Overall, the effects of CO2, warming and clipping treatments on aboveground tissue N concentrations were much greater than on belowground tissue.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California - Davis, Davis, CA, USA avolder@ucdavis.edu.

No MeSH data available.