Nitrogen supply improved plant growth and Cd translocation in maize at the silking and physiological maturity under moderate Cd stress

Tingting An; Yujie Wu; Bingcheng Xu; Suiqi Zhang; Xiping Deng; Yi Zhang; Kadambot Hm Siddique; Yinglong Chen

doi:10.1016/j.ecoenv.2021.113137

Nitrogen supply improved plant growth and Cd translocation in maize at the silking and physiological maturity under moderate Cd stress

Ecotoxicol Environ Saf. 2022 Jan 15:230:113137. doi: 10.1016/j.ecoenv.2021.113137. Epub 2021 Dec 31.

Authors

Tingting An¹, Yujie Wu¹, Bingcheng Xu², Suiqi Zhang², Xiping Deng², Yi Zhang³, Kadambot Hm Siddique⁴, Yinglong Chen⁵

Affiliations

¹ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China; College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China.
² State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China.
³ College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address: zhangyi.1978@163.com.
⁴ The UWA Institute of Agriculture, & School of Agriculture and Environment, The University of Western Australia, Perth 6009, Australia.
⁵ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China; The UWA Institute of Agriculture, & School of Agriculture and Environment, The University of Western Australia, Perth 6009, Australia. Electronic address: yinglong.chen@uwa.edu.au.

PMID: 34979312
DOI: 10.1016/j.ecoenv.2021.113137

Abstract

Soil cadmium (Cd) contamination is a serious problem on agricultural land. Adequate nitrogen (N) may help ameliorate plant fitness under Cd stress. This study examined the role of N application in improving maize tolerance to Cd stress. Two maize genotypes, Zhongke11 (larger root system) and Shengrui999 (smaller root system), were grown in a loessal soil amended with Cd (Cd0, no added Cd; Cd1, 20 mg kg^-1 soil as CdCl₂·2.5 H₂O) and N (N0, no added N; N1, 100 mg kg^-1 soil as urea) under greenhouse, and plants were assessed at silking and maturity stages. Maize plants exhibited moderate Cd stress with significantly reduced grain yield, especially under low N (N1). Roots accumulated more Cd than above-ground parts. Grain Cd concentration was the least (0.05-0.06 μg g^-1) among all organs which is below the safety threshold. Leaf Cd concentrations (0.24-1.18 mg kg^-1) were also under the toxicity threshold. Nitrogen addition significantly improved plant growth, chlorophyll content, photosynthesis traits, and tissue Cd contents, and reduced Cd concentration in soil compared to N0 treatment. Nitrogen promoted Cd bioconcentration and translocation factors in stem and leaves. Cadmium stress reduced N fertilizer agronomic efficiency at maturity. At maturity, root Cd content was positively correlated with root N and calcium accumulation, and stem Cd content was positively correlated with stem N content (both P ≤ 0.05). Genotypes with different root system size differed in response to Cd toxicity and / or N deficit. The small-rooted genotype Shengrui999 was more tolerant to moderate Cd stress than the large-rooted Zhongke11. Addition of N ameliorated Cd stress in both maize genotypes by improving plant growth performance, and regulating Cd translocations among plant organs.

Keywords: Amelioration; Cd accumulation and distribution; Cd stress; Genotypic variation; Maize; Nitrogen supply; Root system size.