Plant growth promoting bacteria enhances photosynthesis, nodulation and root system architecture in lentil under lead toxicity

Abstract

The usage of plant growth-promoting bacteria (PGPB) in mitigation of harmful effects of lead (Pb) toxicity in plants and bioremediation of it from soils is a sustainable, effective and low-cost strategy. The experiment was laid out to investigate the role of PGPB on morphological and physiological growth, root system architecture and nodulation of lentil under Pb stress. The experiment was conducted according to completely randomized factorial design with four replications at the laboratory of the Field Crops Department, Siirt University, Siirt in 2022. The four Pb levels and three bacterial inoculations were used in the experiment. Plant height, seedling fresh weight, root fresh weight, seedling dry weight, root dry weight, total chlorophyll content, taproot length, number of lateral roots, total root length and number of nodule varied between 15.7-25.9 cm, 0.123-0.235 g, 0.019-0.092 g, 0.0104-0.0326 g, 0.0076-0.0146 g, 27.9-47.2%, 8.9-19.2 cm, 4.00-14.67, 17.6-44.8 cm and 1.37-10.63, respectively. Bio-priming with PGPB containing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity increased dry matter accumulation up to 56.1% and 22.9% in shoots and roots, respectively. Chlorophyll content enhanced up to 17.9% compared with control application. Besides, root system architecture and nodule formation were improved by bio-priming both under stress and non-stress conditions. Bio-priming with PGPB may be a sustainable solution to mitigate oxidative stress and promote plant growth and yield in lentil under Pb-contaminated soils.