Changes in leaf growth, net photosynthetic rate (PN), incorporation pattern of photosynthetically fixed 14CO2 in leaves 1-4 from top, roots, and rhizome, and in essential oil and curcumin contents were studied in turmeric plants grown in nutrient solution at boron (B) concentrations of 0 and 0.5 g m-3. B deficiency resulted in decrease in leaf area, fresh and dry mass, chlorophyll (Chl) content, and PN and total 14CO2 incorporated at all leaf positions, the maximum effect being in young growing leaves. The incorporation of 14CO2 declined with leaf position being maximal in the youngest leaf. B deficiency resulted in reduced accumulation of sugars, amino acids, and organic acids at all leaf positions. Translocation of the metabolites towards rhizome and roots decreased. In rhizome, the amount of amino acids increased but content of organic acids did not show any change, whereas in roots there was decrease in contents of these metabolites as a result of B deficiency. Photoassimilate partitioning to essential oil in leaf and to curcumin in rhizome decreased. Although the curcumin content of rhizome increased due to B deficiency, the overall rhizome yield and curcumin yield decreased. The influence of B deficiency on leaf area, fresh and dry masses, CO2 exchange rate, oil content, and rhizome and curcumin yields can be ascribed to reduced photosynthate formation and translocation. and Deeksha Dixit, N. K. Srivastava, S. Sharma.
Changes in growth parameters and 14CO2 and [U-14C]-sucrose incorporation into the primary metabolic pools and essential oil were investigated in leaves and stems of M. spicata treated with etherel and gibberellic acid (GA). Compared to the control, GA and etherel treatments induced significant phenotypic changes and a decrease in chlorophyll content, CO2 exchange rate, and stomatal conductance. Treatment with etherel led to increased total incorporation of 14CO2 into the leaves wheras total incorporation from 14C sucrose was decreased. When 14CO2 was fed, the incorporation into the ethanol soluble fraction, sugars, organic acids, and essential oil was significantly higher in etherel treated leaves than in the control. However, [U-14C]-sucrose feeding led to decreased label incorporation in the ethanol-soluble fraction, sugars, organic acids, and essential oils compared to the control. When 14CO2 was fed to GA treated leaves, label incorporation in ethanol-insoluble fraction, sugars, and oils was significantly higher than in the control. In contrast, when [U-14C]-sucrose was fed the incorporation in the ethanol soluble fraction, sugars, organic acids, and oil was significantly lower than in the control. Hence the hormone treatment induces a differential utilization of precursors for oil biosynthesis and accumulation and differences in partitioning of label between leaf and stem. Etherel and GA influence the partitioning of primary photosynthetic metabolites and thus modify plant growth and essential oil accumulation. and Preety Singh ... [et al.].