Interactive effect of elevated CO₂, drought and weed competition on carbon isotope discrimination (Δ¹³ C) in wheat (Triticum aestivum) leaves

Abstract

An experiment was conducted in open top chambers (OTCs) during 2006–07 to study the carbon isotope discrimination (Δ¹³C) in wheat (Triticum aestivum L. emend Fiori & Paol.) leaves in response to elevated CO₂, drought and competition by weeds (Phalaris minor, Chenopodium album and Avena fatua). It was observed that drought and weed competition had decreased the Δ whereas, elevated CO₂ had increased the Δ and partially ameliorated the negative effects of drought and weeds on Δ. However, the Δ in wheat was not much influenced by stress but, by elevated CO₂ when it was in association with P. minor suggesting the variability in Δ due to variation in competition by different weeds.