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Effects of elevated temperature and CO2 on aboveground-belowground systems: a case study with plants, their mutualistic bacteria and root/shoot herbivores.

Ryalls JM, Riegler M, Moore BD, Lopaticki G, Johnson SN - Front Plant Sci (2013)

Bottom Line: Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT) and elevated atmospheric carbon dioxide (eCO2) are untested.Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively.The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

View Article: PubMed Central - PubMed

Affiliation: Hawkesbury Institute for the Environment, University of Western Sydney Richmond, NSW, Australia.

ABSTRACT
Interactions between above- and belowground herbivores have been prominent in the field of aboveground-belowground ecology from the outset, although little is known about how climate change affects these organisms when they share the same plant. Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT) and elevated atmospheric carbon dioxide (eCO2) are untested. We investigated how eT and eCO2 affected larval development of the lucerne weevil (Sitona discoideus) and colonization by the pea aphid (Acyrthosiphon pisum), on three cultivars of a common host plant, lucerne (Medicago sativa). Sitona discoideus larvae feed on root nodules housing N2-fixing rhizobial bacteria, allowing us to test the effects of eT and eCO2 across trophic levels. Moreover, we assessed the influence of these factors on plant growth. eT increased plant growth rate initially (6, 8 and 10 weeks after sowing), with cultivar "Sequel" achieving the greatest height. Inoculation with aphids, however, reduced plant growth at week 14. eT severely reduced root nodulation by 43%, whereas eCO2 promoted nodulation by 56%, but only at ambient temperatures. Weevil presence increased net root biomass and nodulation, by 31 and 45%, respectively, showing an overcompensatory plant growth response. Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively. Contrary to expectations, aphid colonization was unaffected by eT or eCO2, but there was a near-significant 10% reduction in colonization rates on plants with weevils present belowground. The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

No MeSH data available.


Related in: MedlinePlus

Effects of temperature and cultivar (Hunter River, H; Sequel, S and Trifecta, T) on plant growth (height) 10 weeks after sowing. Mean values (± standard errors) of significant treatment factors (temperature and cultivar) in the final model shown.
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Figure 1: Effects of temperature and cultivar (Hunter River, H; Sequel, S and Trifecta, T) on plant growth (height) 10 weeks after sowing. Mean values (± standard errors) of significant treatment factors (temperature and cultivar) in the final model shown.

Mentions: Plant height was significantly greater at higher temperatures at week 6 (F1,468 = 59.03; P < 0.001), week 8 (F1,468 = 40.11; P < 0.001) and week 10 (F1,468 = 8.56; P = 0.004), whereas CO2 did not affect plant height in these weeks (see Figure 1 for significant effects at week 10). In addition, there were significant differences in height between cultivars in these same weeks (F2,468 = 14.52, P < 0.001; F2,468 = 9.03; P < 0.001; F2,468 = 9.45; P < 0.001), with Sequel being significantly bigger than the other two cultivars overall (Table 1). At week 14, aphids reduced plant height (t1,195 = -2.637; P = 0.008) and there was a significant interaction between CO2 and temperature (F2,468 = 8.21; P = 0.004) whereby eCO2 increased plant growth at 26°C (from 57.5 ± 4.2 mm at aCO2 to 66.4 ± 4.2 mm at eCO2) but not at 30°C. The presence of weevils also interacted with temperature effects (F2,468 = 6.94; P = 0.009), with weevils decreasing overall plant height at 26°C (from 66.9 ± 4.4 mm without weevils to 58.1 ± 3.9 mm with weevils) but not at 30°C (see Figure 2 for all significant treatment factors).


Effects of elevated temperature and CO2 on aboveground-belowground systems: a case study with plants, their mutualistic bacteria and root/shoot herbivores.

Ryalls JM, Riegler M, Moore BD, Lopaticki G, Johnson SN - Front Plant Sci (2013)

Effects of temperature and cultivar (Hunter River, H; Sequel, S and Trifecta, T) on plant growth (height) 10 weeks after sowing. Mean values (± standard errors) of significant treatment factors (temperature and cultivar) in the final model shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3822287&req=5

Figure 1: Effects of temperature and cultivar (Hunter River, H; Sequel, S and Trifecta, T) on plant growth (height) 10 weeks after sowing. Mean values (± standard errors) of significant treatment factors (temperature and cultivar) in the final model shown.
Mentions: Plant height was significantly greater at higher temperatures at week 6 (F1,468 = 59.03; P < 0.001), week 8 (F1,468 = 40.11; P < 0.001) and week 10 (F1,468 = 8.56; P = 0.004), whereas CO2 did not affect plant height in these weeks (see Figure 1 for significant effects at week 10). In addition, there were significant differences in height between cultivars in these same weeks (F2,468 = 14.52, P < 0.001; F2,468 = 9.03; P < 0.001; F2,468 = 9.45; P < 0.001), with Sequel being significantly bigger than the other two cultivars overall (Table 1). At week 14, aphids reduced plant height (t1,195 = -2.637; P = 0.008) and there was a significant interaction between CO2 and temperature (F2,468 = 8.21; P = 0.004) whereby eCO2 increased plant growth at 26°C (from 57.5 ± 4.2 mm at aCO2 to 66.4 ± 4.2 mm at eCO2) but not at 30°C. The presence of weevils also interacted with temperature effects (F2,468 = 6.94; P = 0.009), with weevils decreasing overall plant height at 26°C (from 66.9 ± 4.4 mm without weevils to 58.1 ± 3.9 mm with weevils) but not at 30°C (see Figure 2 for all significant treatment factors).

Bottom Line: Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT) and elevated atmospheric carbon dioxide (eCO2) are untested.Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively.The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

View Article: PubMed Central - PubMed

Affiliation: Hawkesbury Institute for the Environment, University of Western Sydney Richmond, NSW, Australia.

ABSTRACT
Interactions between above- and belowground herbivores have been prominent in the field of aboveground-belowground ecology from the outset, although little is known about how climate change affects these organisms when they share the same plant. Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT) and elevated atmospheric carbon dioxide (eCO2) are untested. We investigated how eT and eCO2 affected larval development of the lucerne weevil (Sitona discoideus) and colonization by the pea aphid (Acyrthosiphon pisum), on three cultivars of a common host plant, lucerne (Medicago sativa). Sitona discoideus larvae feed on root nodules housing N2-fixing rhizobial bacteria, allowing us to test the effects of eT and eCO2 across trophic levels. Moreover, we assessed the influence of these factors on plant growth. eT increased plant growth rate initially (6, 8 and 10 weeks after sowing), with cultivar "Sequel" achieving the greatest height. Inoculation with aphids, however, reduced plant growth at week 14. eT severely reduced root nodulation by 43%, whereas eCO2 promoted nodulation by 56%, but only at ambient temperatures. Weevil presence increased net root biomass and nodulation, by 31 and 45%, respectively, showing an overcompensatory plant growth response. Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively. Contrary to expectations, aphid colonization was unaffected by eT or eCO2, but there was a near-significant 10% reduction in colonization rates on plants with weevils present belowground. The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

No MeSH data available.


Related in: MedlinePlus