Determination of nitrogen depth distributions in cereals using the 14N(d,p0)15N reaction

Nitrogen and protein contents are correlated in agricultural products and therefore determination of nitrogen might be used for plant breeding purposes. The Kjeldahl method is time-consuming and destructive and new methods which are faster and nondestructive are searched for. It is also of great interest to extract information on the distribution of nitrogen in single seeds. In rice for example the most important part of the protein content is removed by polishing the seeds. (d,p) reactions have been used in 14N (Esub(d)=6 MeV) to determine the content and recently the depth distribution of nitrogen in single kernels of seed. The time needed to determine the total nitrogen content and the depth distribution with reasonable statistical accuracy is 1-5 seconds and 10-30 seconds respectively. With the deuteron energy used the analyzed depth was 250 μm and the depth resolution about 10 μm throughout the layer. A comparison, concerning total nitrogen, of this method with the Kjeldahl method was made on individual peas and beans. The results were found to be strongly correlated. The technique to obtain depth distributions of nitrogen was used on high- and low-lysine varieties of barley for which large differences in nitrogen depth distributions were found. (Auth.)