Impact of organic amendments and soil textural class on growth performance and heavy metals uptake in Canna indica.

Phytoremediation offers an eco-friendly and sustainable alternative to conventional remediation technologies; however, the influence of soil organic matter (SOM) and soil texture (ST) on phytostabilization efficiency of ornamental metallophytes remains insufficiently understood. This study evaluates the individual effects of SOM and ST on the growth performance and heavy-metals (Pb, Cd, and Cr(VI)) uptake of Canna indica under multi-metal contamination. Two controlled pot experiments conducted over four months using artificially contaminated soils to study the influence of SOM and ST. Results revealed that SOM significantly enhanced plant growth attributes. At 4% SOM, root length, shoot length, and bulb diameter increased by 63.47%, 53.9%, and 90.6%, respectively, compared to the control. Conversely, metal concentrations in roots and shoots declined with increasing SOM, with Pb, Cd, and Cr(VI) in roots decreasing by 29.8%, 50.65%, and 48.97%, respectively, due to organic complexation and reduced metal bioavailability. Among textural classes, loamy soil exhibited superior growth performance and the lowest metal accumulation due to balanced porosity, higher nutrient retention, and enhanced metal immobilisation. Bio-concentration and translocation factors indicated that C. indica predominantly functions through a phytostabilization mechanism. These findings demonstrate that optimizing SOM amendment and ST can significantly improve phytostabilization efficiency, offering a low-cost and environmentally sustainable strategy for managing multi-metal contaminated soils.