title: Timing of foliar Zn application plays a vital role in minimizing Cd accumulation in wheat.
abstract: Due to chemical and biochemical similarities between cadmium (Cd) and zinc (Zn), application of Zn may minimize Cd uptake by plants and ameliorate its toxicity. However, there is poor understanding of the comparative effectiveness of the foliar Zn application at different growth stages on Cd toxicity and accumulation in wheat. The present study was carried out to compare the effectiveness of foliarly applied Zn at different stages of plant growth to minimize Cd accumulation in wheat grains. Wheat (cv AARI-2011) was grown at three levels of soil Cd (0, 2.5, and 5.0 mg kg(-1)). Foliar application of Zn was carried out at either tillering, jointing, booting, heading, or grain filling stage using 0.05 % w/v aqueous solution of ZnSO4 · 7H2O. Increasing soil Cd had a negative effect on growth and yield attributes, including tiller production, root length and dry weight, plant height, 100-grain weight and grain and straw yield. Zinc foliar spray increased grain yield by increasing tiller production; importantly, an application at booting was more effective than at other stages. Foliarly applied Zn decreased Cd concentration in the roots, straw, and grain. Similar to grain yield, the largest decrease (74 %) in Cd concentration was associated with Zn foliar spray at booting. Grain yield was negatively related to grain Cd concentration which in turn showed a negative relationship with Zn concentration in leaves and grains. It is concluded that the booting stage is the suitable time for foliar application of Zn to (i) effectively minimize a Cd-induced loss in grain yield and (ii) decrease grain Cd concentration.
authors.affiliation: Department of Environmental Health, College of Applied Medical Sciences, University of Dammam, Dammam, Kingdom of Saudi Arabia. smferoz@uod.edu.sa.
authors.lastname: Saifullah
authors.affiliation: Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan.
authors.forename: Hina
authors.initials: H
authors.lastname: Javed
authors.affiliation: Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan.|Soil Science Division, Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, 38000, Pakistan.
authors.forename: Asif
authors.initials: A
authors.lastname: Naeem
authors.affiliation: School of Earth and Environment, University of Western Australia, 35 Sterling Highway, Crawley, WA, 6009, Australia.
authors.forename: Zed
authors.initials: Z
authors.lastname: Rengel
authors.affiliation: Department of Environmental Health, College of Applied Medical Sciences, University of Dammam, Dammam, Kingdom of Saudi Arabia.
authors.forename: Saad
authors.initials: S
authors.lastname: Dahlawi
mesh_terms: D002104:Cadmium / Q000032:analysis; D002523:Edible Grain / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism*; D018517:Plant Roots / Q000737:chemistry; D012987:Soil; D012989:Soil Pollutants / Q000378:metabolism*; D014908:Triticum / Q000254:growth & development / Q000502:physiology*; D015032:Zinc / Q000032:analysis / Q000378:metabolism*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D015032:Zinc
keywords: Cadmium translocation; Grain Cd; Grain Zn; Wheat; Zinc foliar spray