THE SUBSTRATE UTILIZATION AND CONCENTRATION OF C-14 PHOTOSYNTHATES INCITRONELLA UNDER FE DEFICIENCY

Changes in the utilization pattern of primary substrate, viz. [U-C-14] acetate, (CO2)-C-14 and [U-C-14] saccharose, and the contents of C-14 fixation products in photosynthetic metabolites (sugars, amino acids, and organic acids) were determined in Fe-deficient citronella in rela tion to the essential oil accumulation. There was an overall decrease in photosynthetic efficiency of the Fe-deficient plants as evidenced b y lower levels of incorporation into the sugar fraction and essential oil after (CO2)-C-14 had been supplied. When acetate and saccharose we re fed to the Fe-deficient plants, despite a higher incorporation of l abel into sugars, amino acids, and organic acids, there was a lower in corporation of these metabolites into essential oils than in control p lants. Thus, the availability of precursors and the translocation to a site of synthesis/accumulation, severely affected by Fe deficiency, i s equally important for the essential oil biosynthesis in citronella.