Role of exogenously applied triacontanol in amelioration of chromium stress in Pisum sativum by enhanced nutrition orchestration, growth and proline content

Abstract

Chromium (Cr) is one of the most phytotoxic elements. Its level in agricultural soil is rising alarmingly, mainly due to anthropogenic activities. Triacontanol (TRIA), a plant growth regulator, promotes a variety of metabolic processes that improve plant growth and development. Current study elucidates the metal stress attenuation potential of TRIA in Pisum sativum (pea) seedlings growing in Cr contaminated conditions. For this purpose, soil was contaminated with Cr (100 mg kg−1) by using K2Cr2O7. Three concentrations of TRIA (10, 20, and 30 μmol L−1) were used to prime P. sativum seeds, which subsequently grown in control and Cr-spiked soil. When exposed to Cr, P. sativum exhibited stunted growth, retarded photosynthetic activity, and chlorophyll pigment production. Growth suppression in Cr-treated plants was also ascribed to reduced mineral content (K+, Na+, Zn2+, and Mg2+), gas exchange characteristics, and reduced DPPH activity. Plants grown from TRIA-treated seeds exhibited increased growth, decreased loss of photosynthetic pigments, and reduced oxidative stress mediated by Cr through improving non-enzymatic antioxidants such as proline, phenolics, and carotenoids. Nevertheless, plants developed from seeds primed with 20 μmol L−1 TRIA showed enhanced growth, fresh and dry biomass, gas exchange characteristics, and improved uptake of mineral ions. According to the current study, seed priming with TRIA ameliorates Cr-toxicity and enables P. sativum cultivation in Cr-contaminated environment. TRIA1 and TRIA3 treatment also reduced Cr intake by 26.1 % and 16 % respectively in comparison to Cr- alone treatment. These results improve the understanding of the TRIA-related stress mitigation pathway in P. sativum crops. Additionally, a study about the potential of TRIA to reduce stress in other agronomic and horticultural crops will help to increase crop production.