Deuterium heterogeneity in starch and cellulose nitrate of cam and C3 plants

Starch and cellulose were extracted and nitrated from well illuminated photosynthetic tissues of seven C3 species and nine CAM species. Results show that (i) δD values of cellulose nitrate from CAM species are on average 73%ο higher than cellulose nitrate of C3 plants; (ii) δD values of nitrated cellulose from C3 and CAM species are significantly higher than their respective nitrated starch and (iii) the lower the δD value of starch the higher the difference between δD of nitrated cellulose and starch, with CAM plants showing a greater enrichment. These results confirm the model that deuterium enrichment occurs during carbohydrate metabolism in the cytoplasm, and are consistent with the hypothesis that deuterium enrichment of the cytoplasmic carbohydrate pool occurs to a greater extent in CAM plants.