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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.


Change in green leaf N concentrations due to (A) increased atmospheric CO2 concentration (756 p.p.m.) compared with ambient atmospheric CO2 concentration (405 p.p.m.), (B) increased clipping frequency, (C) higher night-time warming compared with ambient air temperatures (+2.0/+4.4 °C above ambient, day/night) and (D) continuous warming above ambient (+3.0 °C), as affected by harvest period. The dashed lines indicate the average response to elevated atmospheric CO2 levels (A), increased clipping frequency (B), high night-time warming (C) and continuous warming (D). Data presented are least square means and SEM based on a full model. Different letters indicate statistically significant differences between harvest periods at P < 0.05 using Student's t LSD test.
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PLV094F1: Change in green leaf N concentrations due to (A) increased atmospheric CO2 concentration (756 p.p.m.) compared with ambient atmospheric CO2 concentration (405 p.p.m.), (B) increased clipping frequency, (C) higher night-time warming compared with ambient air temperatures (+2.0/+4.4 °C above ambient, day/night) and (D) continuous warming above ambient (+3.0 °C), as affected by harvest period. The dashed lines indicate the average response to elevated atmospheric CO2 levels (A), increased clipping frequency (B), high night-time warming (C) and continuous warming (D). Data presented are least square means and SEM based on a full model. Different letters indicate statistically significant differences between harvest periods at P < 0.05 using Student's t LSD test.

Mentions: Across treatments and harvests, harvested green leaf tissue N concentrations were decreased by 15.6 % under elevated atmospheric CO2 concentration (Fig. 1A) and increased by 32.0 % by frequent clipping (Fig. 1B). The influence of elevated CO2 and clipping frequency on leaf N concentration varied with harvest period (Fig. 1, Table 1, see Supporting Information—Tables S1–S3 for tissue C and N concentrations and C : N ratios on each harvest date). The decline in leaf tissue N concentration due to elevated CO2 was stronger in spring and summer (November–May and September–March) than during the winter (Fig. 1A, ), while the effect of clipping frequency was stronger in the winter and fall (May–December, March–May) than in the spring and summer (Fig. 1B, Pharvest date × clipping < 0.001).Table 1.


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)

Change in green leaf N concentrations due to (A) increased atmospheric CO2 concentration (756 p.p.m.) compared with ambient atmospheric CO2 concentration (405 p.p.m.), (B) increased clipping frequency, (C) higher night-time warming compared with ambient air temperatures (+2.0/+4.4 °C above ambient, day/night) and (D) continuous warming above ambient (+3.0 °C), as affected by harvest period. The dashed lines indicate the average response to elevated atmospheric CO2 levels (A), increased clipping frequency (B), high night-time warming (C) and continuous warming (D). Data presented are least square means and SEM based on a full model. Different letters indicate statistically significant differences between harvest periods 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

PLV094F1: Change in green leaf N concentrations due to (A) increased atmospheric CO2 concentration (756 p.p.m.) compared with ambient atmospheric CO2 concentration (405 p.p.m.), (B) increased clipping frequency, (C) higher night-time warming compared with ambient air temperatures (+2.0/+4.4 °C above ambient, day/night) and (D) continuous warming above ambient (+3.0 °C), as affected by harvest period. The dashed lines indicate the average response to elevated atmospheric CO2 levels (A), increased clipping frequency (B), high night-time warming (C) and continuous warming (D). Data presented are least square means and SEM based on a full model. Different letters indicate statistically significant differences between harvest periods at P < 0.05 using Student's t LSD test.
Mentions: Across treatments and harvests, harvested green leaf tissue N concentrations were decreased by 15.6 % under elevated atmospheric CO2 concentration (Fig. 1A) and increased by 32.0 % by frequent clipping (Fig. 1B). The influence of elevated CO2 and clipping frequency on leaf N concentration varied with harvest period (Fig. 1, Table 1, see Supporting Information—Tables S1–S3 for tissue C and N concentrations and C : N ratios on each harvest date). The decline in leaf tissue N concentration due to elevated CO2 was stronger in spring and summer (November–May and September–March) than during the winter (Fig. 1A, ), while the effect of clipping frequency was stronger in the winter and fall (May–December, March–May) than in the spring and summer (Fig. 1B, Pharvest date × clipping < 0.001).Table 1.

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.