
%0 Journal Article
%A Denton, Tricia M. 
%A Schmidt, Susanne 
%A Critchley, Christa 
%A Stewart, George R. 
%T Natural abundance of stable carbon and nitrogen isotopes in <emph type="2">Cannabis sativa</emph> reflects growth conditions
%J Functional Plant Biology
%D 2001/10/09
%V 28
%N 10
%P 1005-1012
%K Cannabis sativa L., forensic botany, stable isotopes, &#948;13C, &#948;15N.
%R https://doi.org/10.1071/PP01066
%U https://www.publish.csiro.au/paper/PP01066 
%X Stable carbon and nitrogen isotope signatures (&#948;13C and &#948;15N) of Cannabis sativa were assessed for their usefulness to trace seized Cannabis leaves to the country of origin and to source crops by determining how isotope signatures relate to plant growth conditions. The isotopic composition of Cannabis examined here covered nearly the entire range of values reported for terrestrial C3 plants. The &#948;13C values of Cannabis from Australia, Papua New Guinea and Thailand ranged from &#8211;36 to &#8211;25&#8240;, and &#948; 15N values ranged from &#8211;1.0 to 15.8&#8240;. The stable isotope content did not allow differentiation between Cannabis originating from the three countries, but &#948;13C values of plantation-grown Cannabis differed between well-watered plants (average &#948;13C of&#8211;30.0&#8240;) and plants that had received little irrigation (average &#948;13C of &#8211;26.4&#8240;). Cannabis grown under controlled conditions had &#948;13C values of &#8211;32.6 and &#8211;30.6&#8240; with high and low water supply, respectively. These results indicate that water availability determines leaf 13C in plants grown under similar conditions of light, temperature and air humidity. The &#948;13C values also distinguished between indoor- and outdoor-grown Cannabis; indoor-grown plants had overall more negative &#948;13C values (average &#8211;31.8&#8240;) than outdoor-grown plants (average &#8211;27.9&#8240;). Contributing to the strong 13C-depletion of indoor-grown plants may be high relative humidity, poor ventilation and recycling of 13C-depleted respired CO2. Mineral fertilizers had mostly lower &#948;15N values (&#8211;0.2 to 2.2&#8240;) than manure-based fertilizers (7.6 to 22.7&#8240;). It was possible to link &#948;15N values of fertilizers associated with a crop site to soil and plant &#948;15N values. The strong relationship between soil, fertilizer, and plant &#948;15N suggests that Cannabis &#948;15N is determined by the isotopic composition of the nitrogen source. The distinct d15N values measured in Cannabis crops make &#948;15N an excellent tool for matching seized Cannabiswith a source crop. A case study is presented that demonstrates how &#948;13C and &#948;15N values can be used as a forensic tool. 
