Effects of elevated CO2 on vitamin E concentrations in grains of two wheat cultivars – A FACE study

Sabine Tausz-Posch¹, Violace A. Putri¹, Saman Seneweera¹, Robert Norton^1,2, Glenn Fitzgerald³ and Michael Tausz⁴
 

¹ Department of Agriculture and Food Systems, The University of Melbourne, Private Bag 260, Horsham VIC 3401, Australia, Email sposch@unimelb.edu.au
² International Plant Nutrition Institute, 54 Florence St, Horsham VIC 3401, Australia
³ Victorian Department of Primary Industries, Private Bag 260, Horsham VIC 3401, Australia
⁴ Department of Forest and Ecosystem Science, The University of Melbourne, Water St, Creswick VIC 3363, Australia
 

Abstract

Vitamin E is essential for the human diet. Wheat (Triticum aestivum L.), as a basic food staple for the human diet, supplies not only significant amounts of dietary carbohydrates and proteins, but is also abundant in structurally related vitamin E compounds called tocols. While it has been shown that rising atmospheric CO₂ [CO₂] decreases protein as well as macro- and micro nutrients in wheat grains, possible effects of elevated [CO₂] (e[CO₂]) on tocols have received little attention. This study compares the tocols (α−, γ−, δ−tocopherols and α−, β−, γ−tocotrienol) of two wheat cultivars (Janz and Zebu) under two CO₂ levels (ambient a[CO₂] ~390 ppm, e[CO₂] ~550 ppm) in order to study intra-specific variability of responses to e[CO₂]. Plants were grown within the Australian Grains Free Air Carbon Dioxide Enrichment (AGFACE) facility, Horsham (Victoria). Tocols of grains were analysed three weeks before and at maturity. Tocol concentrations were not affected by CO₂ treatment. Cultivar specific differences were only found for tocotrienols but not for tocopherols with Zebu having significantly greater α−, β−, γ−tocotrienol concentrations than Janz. Also, tocol concentrations decreased from early to late sampling date, except for α-tocotrienol, which increased, and γ-tocopherol, which did not change between sampling dates. Based on these findings our data suggest that rising CO₂ concentrations do not impact tocol concentrations in wheat grains, which has positive implications for the food quality of a future climate.
 

Key Words

Triticum aestivum, vitamin E, elevated CO₂, climate change, Free Air Carbon Dioxide Enrichment (FACE)

http://www.regional.org.au/au/asa/2012/climate-change/8092_tausz.htm