RESEARCH ARTICLE Photosynthesis and growth response of maize (Zea mays L.) hybrids exposed to cadmium stress Tasneem Akhtar 1,2 & Muhammad Zia-ur-Rehman 1 & Asif Naeem 3 & Rab Nawaz 4 & Shafaqat Ali 5 & Ghulam Murtaza 1 & Muhammad Aamer Maqsood 1 & Muhammad Azhar 1 & Hinnan Khalid 1 & Muhammad Rizwan 5 Received: 11 October 2016 /Accepted: 11 December 2016 # Springer-Verlag Berlin Heidelberg 2016 Abstract Cadmium (Cd) is a biologically non-essential heavy metal while the cultivation of Cd-tolerant varieties/ hybrids (V) seems the most promising strategy for remedia- tion of Cd-contaminated soils. For this, 24-day-old seedlings of seven maize hybrids, DKC 65-25, DKC 61-25, DKC 919, 23-T-16, 32-B-33, 31-P-41, and Syn hybrid, were grown in hydroponic conditions for 21 additional days in various Cd concentrations (0, 5, 10, and 15 μM). Effects of variety, Cd, and their interaction were highly significant (p ≤ 0.05) for studied plant agronomic and physiological traits except the V × Cd interaction for leaf chlorophyll content, root-shoot length, and root dry weight. The Cd accumulation in root and shoot increased gradually with increasing Cd treatments while copper (Cu), zinc (Zn), and manganese (Mn) uptake was decreased in all hybrids. The reduction in root and shoot biomass and Cd uptake was lower in 32-B-33 and 23-T-16 compared to other hybrids. The highest accumulation of Cu, Zn, and Mn was observed in 32-B-33, DK C65-25, and 31-P- 41, respectively. The differential uptake and accumulation of Cd by maize hybrids may be useful in selection and breeding for Cd-tolerant genotypes. Keywords Cadmium . Chlorophyll contents . Gas exchange parameters . Growth . Micronutrients . Maize hybrids Introduction Accumulation of heavy metals in agricultural soils mainly results due to anthropogenic activities such as application of contaminated effluents, industrial waste, phosphate fertilizers, herbicides and pesticides, agrochemicals, and sewage sludge (Adrees et al. 2015; Rehman et al. 2015; Rizwan et al. 2016a). Coupled with these anthropogenic activities, volcanic erup- tion, forest fires, run off, and production of sea salt aerosols are among the various natural sources of heavy metal release into the environment (Nagajyoti et al. 2010). Among heavy metals, cadmium (Cd) is widely distributed in world soils both naturally as well as anthropogenically (Choppala et al. 2014; Du et al. 2014). Several studies have reported that Cd toxicity decreased the plant growth and biomass by generating reac- tive oxygen species at cellular and subcellular levels (Rizwan et al. 2016b, 2016c). The Cd toxicity also decreased the pho- tosynthetic pigments and gas exchange characteristics in a variety of plant species (Li et al. 2015; Lysenko et al. 2015; Tauqeer et al. 2016). Cd mainly enters into humans via food crops grown in Cd-contaminated soil (Rizwan et al. 2016a, 2016b). The Cd toxicity in humans has caused a number of disorders such as bone fracture, kidney failure, mental abnor- malities, hypertension, and various skin disorders (Song et al. 2015). Similarly, Cd is also toxic to animals, causing distur- bances in their metabolic activities along with various lethal diseases, which occur by grazing or engulfing the Cd- contaminated fodder and other crops (Wang et al. 2016a). Responsible editor: Elena Maestri * Muhammad Rizwan mrazi1532@yahoo.com 1 Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad, Pakistan 2 Department of Arid Land Agriculture, King Abdul Aziz University, Jeddah, Saudi Arabia 3 Soil Science Division, Nuclear Institute for Agriculture and Biology, Faisalabad, Pakistan 4 Department of Environmental Sciences, The University of Lahore, Lahore, Pakistan 5 Department of Environmental Science, Government College University Faisalabad, Faisalabad, Pakistan Environ Sci Pollut Res DOI 10.1007/s11356-016-8246-0