© 2017 PP House Phyto-toxic Efect of Heavy Metal (CdCl 2 ) on Seed Germinaton, Seedling Growth and Antoxidant Defence Metabolism in Wheat (Tritcum aestvum L.) Variety HUW-234 Anaytullah Siddique * and Anand Prakash Dubey Dept. of Plant Physiology, Insttute of Agricultural Sciences, RGSC, Banaras Hindu University, Varanasi, U.P. (221 005), India The experiments were conducted to assess the phytotoxic efect of heavy metal (CdCl 2 ). The responses of treatment efect comprises the variables germinaton %, length (cm), fresh weight and dry weight (mg) of shoot and root, root/shoot rato, seed vigour index (SVI), reducing sugar, non reducing sugar, total sugar (mg g -1 ), chlorophyll content (mg g -1 ), cadmium uptake (ppm g -1 ), proline content (µg g -1 ), relatve water content (RWC%) and superoxide dismutase (SOD, unit×10 2 g -1 f. weight min -1 ). CdCl 2 treated sets showed reducton in percent of seed germinaton, length (cm), fresh weight and dry weight (mg) of shoot and root, root/shoot rato, seed vigour index (SVI) with increasing the concentratons of CdCl 2 in comparison to control set. A reducton in breakdown of reducing sugar to non reducing sugar and total sugar is correlated with decline of amylase actvity along with increasing the concentratons of CdCl 2 in comparison to control one. The chlorophyll content was found in decreasing trend with increasing the concentratons of CdCl 2 in comparison to control. However, the uptake of cadmium was increased with increasing the concentratons up to 100 ppm CdCl 2 . The proline content and superoxide Dismutase (SOD) was found to be high in higher concentratons of CdCl 2 treated set and while the enhancement was started since inital concentraton CdCl 2 (i.e., 25 ppm). However, the least amount was recorded in control set. On the contrary, RWC% was found to be reduced with increasing the concentratons of CdCl 2 up to 100 ppm even though the maximum RWC% was measured in control set. 1. Introducton Wheat (Tritcum aestvum L.) belongs to family Gramineae and is one of the leading cereals of many countries in respect to growth, producton and consumpton of the world (Farooq et al., 2011a). India is the world’s second largest producer of wheat (Goncalves et al., 2011). Thus, it is important to study the toxicity of heavy metals on this crop. Metal contaminaton is always increasing by the actvites of human which interferes with the environment and makes adverse conditon for living organism. Some plant species have capacity to grow in the metal contaminated soil and accumulate high amount of heavy metals (hyper-accumulaton) as an eco-physiological adaptaton in Metalliferous soil. Among the contaminatons heavy metals Pb, Cd, Hg, As, Ni, and Se are emerging problems for all over worlds. (Ahmad and Ashraf, 2011; Ahmad et al., 2011a). Cadmium (Cd) is one of the most common toxic metals present in the environment that induces various toxic efects in plants even at low doses. Contaminaton of soil in cultvated felds with toxic heavy metals such as cadmium, copper, nickel and zinc has emerged as a new challenge to agriculture (Singh et al., 2007). Inital development of the plant, comprises various processes of seed germinaton (Dominguez and Cejudo, 2014) that culminates the metabolic transformatons that trigger the development of the embryonic axis, consequently, the emergence of radical (Oliveira et al., 2013). On the other hand, heavy metals are abiotc factors that may interfere in the development of seed germinaton. The presence of cadmium permanently in the soil contaminates water and impedes the absorpton of plant nutrients causing morphological, physiological, biochemical and structural changes in plants (Augusto et al., 2014). The immobilizaton of cadmium outside of the plant or inside of the root may be one of the frst barriers of the plant against toxicity to the heavy metal since cadmium levels are highest in roots rather than in leaves, with low transport level from the root to the aerial segment of the plant (Chaves and Souza, 2014). Although, several studies about Cd toxicity to the wheat have been reported but stll it is needed to explore Cd toxicity in wheat crop (Shaf et al., 2010; Rizwan et al., 2016). 2. Materials and Methods A lab experiment was conducted in the Department of Plant Heavy metal, CdCl 2 , wheat, SOD, SVI, RWC%, proline Keywords: Abstract Article History Manuscript No. AR1684 Received in 9 th September, 2016 Received in revised form 19 th February, 2017 Accepted in fnal form 19 th March, 2017 Anaytullah Siddique e-mail: anaytullahsiddique@gmail.com Corresponding Author 261 International Journal of Bio-resource and Stress Management 2017, 8(2):261-267 Doi: HTTPS://DOI.ORG/10.23910/IJBSM/2017.8.2.1684 Full Research