Unveiling the Synergistic Effects of Auxin and Compost Interaction for Enhancing Cauliflower Growth in Nickel-Contaminated Soil

Abstract

Nickel (Ni) is widely distributed in the environment due to activities of living organisms especially human beings, natural resources, weathering of rocks, eruptions of a volcano, and abiotic factors like wind-blown dust, and metallurgical, chemical and food industries processes. Human and growth of plants can be affected due to excessive amount of nickel. Different approaches such as (physical, chemical, and biological) are used to remove nickel from the soil but as compared to other methods biological techniques are advantageous due to their environment-friendly nature and cost effectiveness. Therefore, the use of plant growth regulator and compost plays an important role in growth and yield promotion of various plants in nickel contaminated soil.   Hence a pot trial was carried out to evaluate the cumulative use of auxin and compost on growth and uptake of nickel by cauliflower. Auxin was applied by dipping the nursery of cauliflower into auxin solution (10^-4 and 10^-5 M) before transplantation into pots. However, nickel sulphate was added to spike the soil artificially and maintained the nickel concentration @60 mg kg^-1. The experimental units were arranged by completely randomized design (CRD) and each treatment was replicated thrice. Various growth and yield parameters including Ni concentration in root, shoot and fruit were collected to evaluate the effect of compost and auxin. The pot experiment revealed that the use of combined application of auxin as a plant growth regulator and compost enhanced the growth and yield of cauliflower in nickel-contaminated soil. However, their cumulative application reduces the Ni uptake as compared to their control and minimum Ni concentration was observed in fruit.