Auxin-mediated growth of rice in cadmium-contaminated soil

Authors : Hussna FAROOQ, Hafiz Naeem ASGHAR, Muhammad Yahya KHAN, Muhammad SALEEM, Zahir Ahmad ZAHIR

Pages : 272-276

Doi:10.3906/tar-1405-54

View : 10 | Download : 6

Publication Date : 2015-04-01

Article Type : Research Paper

Abstract :Pollution from heavy metals is a global problem that is very dangerous to the environment. Among the heavy metals, cadmium is receiving more and more attention because it is one of the most ecotoxic, making it very harmful for biological activity in soil, biodiversity, plant metabolism, and human and animal health. Phytohormones, produced by plants, control or regulate germination, growth, metabolism, or other physiological activities, and they can alleviate the toxic effects of heavy metals on plant growth. Auxin is the most abundant natural growth hormone, controlling apical dominance, tropism, elongation of shoots, and initiation of roots in plants. However, cadmium stress causes the degradation of indigenous auxin. To cope with this, auxin may be applied exogenously. To evaluate the role of auxin in cadmium -contaminated soil, different levels of the auxin precursor L-TRP were applied to plants growing in contaminated soil. Rice seedlings were dipped in a L-TRP solution for 2 h and transplanted into potted soil contaminated with 30 mg kg1 cadmium. The results showed that the exogenous application of L-TRP improved the growth and yield of treated plants both in normal and contaminated soil. The data of different parameters showed that L-TRP enhanced plant height insert ignore into journalissuearticles values(12.54%);, the number of tillers insert ignore into journalissuearticles values(25.53%);, the number of panicles insert ignore into journalissuearticles values(19.04%);, the 1000 grain weight insert ignore into journalissuearticles values(19.28%);, and the paddy yield insert ignore into journalissuearticles values(11.78%); in cadmium-contaminated soil, as compared to plants grown in the absence of L-TRP with the same level of contamination. L-TRP increased the uptake of cadmium in rice straw while decreasing the translocation of cadmium towards grains, as compared to plants grown in contaminated soil without L-TRP. This experiment revealed the possibility of using L-TRP to improve plant growth and soil health in contaminated soil.
Keywords : Contamination, heavy metals, L tryptophan, plant growth regulators