Cultivar variation in yield, metabolite translocation and partitioning of ~(14)CO_2 assimilated photosynthate into essential oil and curcumin of turmeric (Curcuma longa L.)

摘要

Cultivar variations have been investigated in Curcuma longa (viz. Rashmi, Krishna, Roma, CL-315, CEL-6, CL-70, CL-13 and CL-16) collected from various locations for photosynthetic capacity and ~(14)CO_2 incorporation into the primary metabolites (sugars, amino acids and organic acids) in relation to essential oil and curcumin accumulation. There are significant differences among C. longa cultivars in growth characteristics, viz. leaf area, leaf area ratio, leaf stem ratio and in photosynthetic characteristics, viz. CO_2 exchange rate and chlorophyll content. Total ~(14)CO_2 incorporation to ethanol soluble and insoluble fractions was maximum in cv. Krishna and was minimum in CL-16. In general assimilate partitioning to sugars was maximum followedby organic acids and amino acids in leaf, pseudostem, rhizome and roots. Maximum content of assimilated ~(14)C in oil was found in cv. CL-315 while in cv. Rashmi maximum content was in curcumin. Correlation analysis revealed significant positive association between ~(14)C content in curcumiu and leaves, rhizome and roots. The study emphasizes that the partitioning of photoassimilated metabolites into various plant parts depends on the biosynthetic capacity of the organs and their rate of secondary metabolite accumulation.