Exogenous triacontanol provides tolerance against arsenic-induced toxicity by scavenging ROS and improving morphology and physiological activities of Mentha arvensis L.

Arsenic (As), recognized as a toxic metalloid globally, has posed a serious threat to soil, plants and aquatic resources. Arsenic restrain fundamental processes of plant grown under the As-contaminated soil which are the worst sufferers for their sustenance. Thus, various scientific strategies are being continuously employed for reducing the soil As. In this regard, use of well-known plant growth regulators (PGRs) like triacontanol (TRIA) shown great efficiency towards heavy metals stress tolerance. TRIA is a plant growth promoter that has been proved effective for growth and development of plants under diverse environmental conditions for many decades. The research work was carried out to examine the toxic effects of As on various morphological, physio-biochemical, yield and quality parameters of Mentha arvensis L. and amelioration of the As toxicity through exogenous application of TRIA. Mentha plants were supplemented with various treatments (i) 0 (control), (ii) TRIA (10 M), (iii) As (60 mg kg), (iv) As (80 mg kg), (v) TRIA (10 M) + As (60 mg kg), and (vi) TRIA (10 M) + As (80 mg kg). Several parameters studied during the present investigation were plant height, fresh and dry weights, herbage yield, chlorophyll and carotenoid content, carbonic anhydrase (CA) activity, several chlorophyll fluorescence parameters, superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), proline (PRO), HO content, TBARS content, electrolyte leakage (EL), essential oil content (EO) and yield and microscopic analyses as well as PCA analysis. Arsenic treatment exhibited deleterious effects on the overall growth, photosynthetic, and quality parameters of M. arvensis. However, the toxicity of As was mitigated by the leaf-applied TRIA to the plants, proved advantageous in combating the ROS generation.