Cadmium Phytoextraction Potential of Ricinus communis Significantly Increased with Exogenous Application of Growth Regulators and Macronutrients

ABSTRACT

Phytoremediation has emerged as promising technology for reclamation of metal-polluted sites. The present study was conducted with an aim to assess the hyperaccumulation potential of Ricinus communis for cadmium, with the application of exogenous substances, [nitrogen (N), phosphorus (P) and potassium (K)] and phytohormones [Gibberellic acid (GA₃) and Indole acetic acid (IAA)]. These were applied to increase plant biomass, improve phytoextraction of Cd and its accumulation in aerial parts, with generation of endogenous proline and phenols in R. communis, grown in soil contaminated with 100 mg Cd/Kg. Plant hormones were used only as foliar spray while growth regulators were applied to soil and also used as foliar spray. T4 (Cd+NPK _AS) significantly increased root length, T12 (GA3+ NPK _FS) highly increased stem length and leaf length as compared to control C1 (plant only Cd). FBM was highly increased by N alone or in combination with P, K, and GA₃ foliar sprayed in R. communis. Conclusively, it was found that NPK (foliar) in combination with GA₃ followed by N and IAA, significantly increased biomass, Cd concentration and accumulation in all the treated plants of R. communis. Cadmium bio-concentration values for R. communis were higher than unity (1) i.e. ± 2.54. Highest significant concentration of phenolic and proline in R. communis were recorded in combination treatments of GA₃ and NPK foliar spray while in other plants in NPK addition into soil treatment. Thus, R. communis has the natural potential as hyperaccumulator and further study is required for its industrial implementation in polluted soil.

KEYWORDS:

• Cadmium
• phytoextraction
• phytoaccumulation
• phytoremediation
• exogenous substances
• endogenous contents
• bio concentration factor
• hyperaccumulator plant

Acknowledgements

Higher Education Commission of Pakistan is highly acknowledged for financial support to complete this research work.

Disclosure statement

All the authors declare that no conflict of interest exists.

Additional information

Funding

This work was supported by the Higher Education Commission, Pakistan.