Wild oat and climate change: The effect of CO2concentration, temperature, and water deficit on the growth and development of wild oat in monoculture

Abstract

Seed from six Australian near-isogenic lines of wild oat were germinated and grown in controlled-environment growth chambers under either ambient CO2 (357 parts per million by volume [ppmv]) or elevated CO2 (480 ppmv) at 20/16 C or 23/19 C. Three soil moisture treatments—−0.01 MPa (field capacity), −0.10 MPa, or −1.00 MPa—were imposed. Wild oat lines grown under elevated CO2 had higher seed production and greater plant dry weights, although the response of these variates involved a complex of interactions with temperature, soil moisture, and line. Plant height varied with wild oat line, and plants grown at 20/16 C were taller than those grown at 23/19 C. At 23/19 C, time taken to mature was reduced for some wild oat lines, and elevated CO2 reduced the time taken to maturity for some lines at 20/16 C. There was no significant difference in the level of dormancy developed in freshly harvested caryopses between the two CO2 treatments, but an effect was present in seed that had been after-ripened for 193 d. These results indicate that the main climate change variables ([CO2], soil moisture, and increased temperature) directly influence the growth and development of wild oat and are likely to affect the population dynamics of this species.