Open Access

ARTICLE

Effects of lead (Pb)-induced oxidative stress on morphological and physio-biochemical properties of rice

MURTAZA KHAN^1,*, TIBA NAZAR IBRAHIM AL AZZAWI², MUHAMMAD IMRAN³, ADIL HUSSAIN⁴, BONG-GYU MUN¹, ANJALI PANDE¹, BYUNG-WOOK YUN^1,*

1 Laboratory of Plant Functional Genomics, School of Applied Biosciences, Kyungpook National University, Daegu, 41566, South Korea
2 Ministry of Agriculture State Company for Agriculture Supplies, Baghdad, 10064, Iraq
3 Laboratory of Crop Physiology, School of Applied Biosciences, Kyungpook National University, Daegu, 41566, South Korea
4 Department of Entomology, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa, 23200, Pakistan

* Corresponding Author: Murtaza Khan. Email:

BIOCELL 2021, 45(5), 1413-1423. https://doi.org/10.32604/biocell.2021.015954

Received 26 January 2021; Accepted 15 April 2021; Issue published 12 July 2021

Abstract

In rice, high concentration of lead (Pb) can cause phyto-toxicity affecting several physiological functions. Cultivation of rice varieties that are resistant to Pb-induced oxidative stress is an important management strategy in Pb-contaminated soils. In the current study, we evaluated four different rice cultivars for their response to Pb-induced stress. Three japonica type cultivars X-Jigna, Ediget, and Furat, and one Indica type cultivar Amber 33 were grown in soil containing different Pb concentrations (0 mM, 0.6 mM, and 1.2 mM). The soil was treated with 0 mM or 0.6 mM or 1.2 mM Pb solution one month prior to rice seedling transplantation. Thereafter, four-week-old rice seedlings were transplanted into the treated soil and their responses were observed until maturity. The data revealed that a highest concentration of Pb (1.2 mM) induced significant reduction in agronomic traits such as plant height, number of tillers per plant, number of panicles per plant, and number of spikelets per panicle in all the rice cultivars. However, least reduction in the agronomic traits was observed in X-Jigna, whereas the highest reduction in the agronomic traits was observed in Ediget. Antioxidant activity of catalase (CAT), peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD), was evaluated along with the accumulation of superoxide ions (O₂^.-), protein, proline, chlorophyll, sucrose, glucose, and fructose contents in all the rice cultivars. A significant increase in antioxidant activity and in the accumulation of proline and sucrose contents with the least reduction in the chlorophyll and protein contents was observed in X-Jigna suggesting that X-Jigna is the most tolerant among all the rice cultivars tested against Pb-stress. On the other hand, non-significant and slightly significant increase in the antioxidant activity, less accumulation of proline and sucrose contents, and higher reduction in the chlorophyll and protein contents was observed in Ediget, which further suggest that Ediget is the most susceptible rice cultivar to Pb-stress. In addition, the other rice cultivars Furat and Amber 33, were found to be moderately tolerant to Pb-induced oxidative stress. In summary, our results suggest that tolerance to Pb-induced oxidative stress would be a result of a synergetic action of both enzymatic and non-enzymatic antioxidant systems, leading to a balanced redox status in rice.

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