Increased root herbivory under elevated atmospheric carbon dioxide concentrations is reversed by silicon‐based plant defences

Frew, Adam and Allsopp, Peter G. and Gherlenda, Andrew G. and Johnson, Scott N. (2017) Increased root herbivory under elevated atmospheric carbon dioxide concentrations is reversed by silicon‐based plant defences. Journal of Applied Ecology, 54 (5). pp. 1310-1319. ISSN 0021-8901

Abstract

Predicted increases in atmospheric concentrations of CO2 may alter the susceptibility of many plants to insect herbivores due to changes in plant nutrition and defences. Silicon plays a critical role in plant defence against herbivores, so increasing such silicon‐based defences in plants may help remediate situations where plants become more susceptible to herbivores. Sugar cane (Saccharum spp. hybrid) was subjected to fully factorial treatment combinations of ambient (aCO2) or elevated (eCO2) atmospheric CO2 concentrations; ambient silicon or silicon supplementation; insect‐free or subject to root herbivory by greyback canegrub (Dermolepida albohirtum). A glasshouse study was used to determine how these factors affected rates of photosynthesis, growth, chemistry (concentrations of silicon, carbon, nitrogen and non‐structural carbohydrates). Changes in canegrub mass were determined in the glasshouse pot study, together with more detailed assessment of how eCO2 and silicon supplementation affected performance and feeding behaviour (relative growth rate and relative consumption) in a 24‐h feeding efficiency assay. Elevated CO2 and silicon supplementation increased rates of photosynthesis (+32% and 14%, respectively) and sugar cane biomass (+45% and 69%, respectively). Silicon supplementation increased silicon concentrations in both leaves and roots by 54% and 75%, respectively. eCO2 caused root C : N to increase by 12%. Canegrub performance and consumption increased under eCO2; relative growth rate (RGR) increased by 116% and consumed 57% more root material (suggestive of compensatory feeding). Silicon application reversed these effects, with large decreases in mass change, RGR and root consumption (65% less root mass consumed). Synthesis and applications. Our results suggest future atmospheric carbon dioxide concentrations could lead to increased crop damage by a below‐ground herbivore. Increasing bioavailable silicon in soil stimulated silicon‐based defences which dramatically decreased herbivory and herbivore performance. Our findings suggest future pest management strategies could benefit from characterising deficiencies in bioavailable silicon in agricultural soils and targeted application of silicon fertilisers. Moreover, future breeding programmes should exploit variation in silicon uptake between cultivars to enhance silicon uptake in new crop varieties. Silicon‐based plant defence proved to be highly beneficial for remediating the negative effects of atmospheric change on sugar cane susceptibility to herbivory and could be applicable in other crops.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 13 Nov 2019 02:47
Last Modified: 26 Nov 2019 03:24
Uncontrolled Keywords: atmospheric concentrations of CO2; below‐ground herbivory; climate change ;crop damage; insect herbivore; pest management; plant defence; silicon; sugar cane
Fields of Research : 06 Biological Sciences > 0602 Ecology > 060299 Ecology not elsewhere classified
05 Environmental Sciences > 0503 Soil Sciences > 050303 Soil Biology
06 Biological Sciences > 0607 Plant Biology > 060799 Plant Biology not elsewhere classified
05 Environmental Sciences > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change
Socio-Economic Objective: D Environment > 96 Environment > 9604 Control of Pests, Diseases and Exotic Species > 960499 Control of Pests, Diseases and Exotic Species not elsewhere classified
Identification Number or DOI: 10.1111/1365-2664.12822
URI: http://eprints.usq.edu.au/id/eprint/37287

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