Alleviating Role of Gibberellic Acid in Enhancing Plant Growth and Stimulating Phenolic Compounds in Carrot (Daucus carota L.) under Lead Stress

Muhammad Awais Ghani,Muyassar H Abualreesh,Rukhsanda Aziz,Muhammad Azam,Basharat Ali,Muhammad Mehran Abbas,Aishah Alatawi,Saleem Bahzad,Anam Noor,Rashad Waseem Khan Qadri,Shafaqat Ali,Muhammad Hamzah Saleem

doi:10.3390/su132112329

Abstract

Toxicity of heavy-metals in soil is a major constraint for the production of carrots (Daucus carota L.). Different plant growth regulators are being used to overcome this problem. It has been found that plant growth regulators induce stress tolerance in plants. In this study, the role of exogenously applied plant growth regulator, gibberellic acid (GA3) was examined in soil grown two carrot cultivars under four different levels of lead (0, 50, 100, and 150 mg/kg) with one level of gibberellic acid (50 ppm). Results showed that Pb stress retarded the plant growth and reduced chlorophyll contents in the leaves of both carrot cultivars. A significant decrease was observed in photosynthetic attributes by Pb addition alone. However, exogenously applied GA3 ameliorated the plant growth and chlorophyll contents in the leaves of both carrot cultivars under Pb stressed conditions. Moreover, GA3 also decreased the uptake of Pb concentration in carrot leaves and roots. In addition, GA3 significantly regulated the phenolic compounds concentration in both carrot cultivars under Pb stress. In this study, cultivar T-29 was found to be more tolerant to Pb stress, however, cultivar Mevarick experienced higher damage regarding plant growth under Pb stress.

Highlights

IntroductionExcessive use and accumulation of toxic and dangerous industrial materials destroy our soil, air and water
Treatment of GA3 alone had a significant result on root length, but under Pb stress its amelioration effect was greater at the 100 mg/kg Pb as compared to other treatments
Pb stress only with various amounts decreased the plant height of both cultivars; more reduction occurred in Maverick at 50 mg/kg Pb (Table 2)

Summary

Introduction

Excessive use and accumulation of toxic and dangerous industrial materials destroy our soil, air and water. Among these hazards and toxic materials, different types of heavy metals which can be found everywhere in nature, cause critical harmful impacts on living beings [1]. Heavy metal contamination is causing annoying situations because their presence is harmful to savage life, humans, plants and mostly vegetables [2]. Heavy metals enter into different parts of the plant (via foliar adsorption, specific elements deposition in leaves and root uptake), and contamination of these metals can alter the plant structure [3]. Heavy metals enter into different parts of the plant (via foliar adsorption, specific elements deposition in leaves and root uptake), and contamination of these metals can alter the plant structure [3]. 4.0/).

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