Partitioning of photosynthetically fixed ~(14)CO_2 into oil and curcumin accumulation in Curcuma longa grown under iron deficiency

摘要

Changes in leaf growth, photosynthetic efficiency, and incorporation pattern of photosynthetically fixed ~(14)CO_2 in leaves 1 and 2 from plant apex, in roots, and rhizome induced in Curcuma by growing in a solution culture at Fe concentration of 0 and 5.6 g m~(-3) were studied. ~(14)C was incorporated into primary, metabolites (sugars, amino acids, and organic acids) and secondary metabolites (essential oil and curcumin). Fe deficiency resulted in a decrease in leaf area, its fresh and dry mass, chlorophyll (Chl) content, and CO_2 exchange rate at all leaf positions. The rate of ~(14)CO_2 fixation declined with leaf position, maximum being in the youngest leaf. Fe deficiency resulted in higher accumulation of sugars, amino acids, and organic acids in leaves at both positions. This is due to poor translocation of metabolites. Roots and rhizomes of Fedeficient plants had lower concentrations of total photosynthate, sugars, and amino acids whereas organic acid concentration was higher in rhizomes. ~(14)CO_2 incorporation in essential oil was lower in the youngest leaf, as well as incorporation in curcumin content in rhizome. Fe deficiency influenced leaf area, its fresh and dry masses, CO_2 exchange rate, and oil and curcumin accumulation by affecting translocation of assimilated photosynthates.