
%0 Journal Article
%A Araus, JL 
%A Buxo, R 
%T Changes in Carbon Isotope Discrimination in Grain Cereals From the North-Western Mediterranean Basin During the Past Seven Millenia
%J Functional Plant Biology
%D 1993/02/01
%V 20
%N 1
%P 117-128
%K 
%R https://doi.org/10.1071/PP9930117
%U https://www.publish.csiro.au/paper/PP9930117 
%X Carbon isotope discrimination (&#916;) was determined for kernels of six-row barley and durum wheat cultivated in the north-western Mediterranean basin during the last seven millennia. Samples from the Neolithic, Bronze, Iron and Middle Ages came from different archaeological sites in Catalonia. Samples for the period 1910-20 and 1990 were also analysed. There was a slight decrease (P=0.10, carbonisation-corrected values) in &#916; from the Neolithic to the Iron Age period and a much steeper decrease from the Middle Ages to 1910-20 (P<0.01). Since water-use efficiency and isotope discrimination are negatively correlated, from the pattern of change in &#916; it is suggested that there has been a progressive increase in the water-use efficiency (WUE) of these cereals. Since the Middle Ages this has coincided with increases in atmospheric CO2 concentration. Thus, for a given relative humidity and air temperature, the estimated WUE (measured as the ratio of CO2 assimilation to transpiration) from the Neolithic to the Middle Ages samples ranged between 65-70% of present time WUE values, whereas WUE for 1910-20 was about 86% of present values. 
