Alterations in δ¹³C values of seedling cellulose associated with respiration during germination

δ¹³C values of heterotrophically synthesized cellulose of roots from germinating seeds treated with a respiratory uncoupler were compared with those produced by untreated seed. Seeds or grains having starch as their principal storage substrate synthesized cellulose enriched in ¹³C relative to their substrate. Those having lipids as their principal storage substrate synthesized cellulose depleted in ¹³C relative to their substrate. The respiratory uncoupler decreased respiration and caused lower ¹³C abundance in synthesized cellulose relative to the controls for starch-storing seeds. Decreased respiration, however, caused an increase in ¹³C of synthesized cellulose from lipid-storing seeds. The observed isotopic enrichment of cellulose with increase in respiration in the starch-storing seeds is consistent with the hypothesis that stems and roots of plants are isotopically enriched relative to leaves because of respiration.