Subcellular and Chemical Mechanisms Affecting the Cultivar-Dependent Cd Accumulation of Water Spinach

In recent years, lots of studies have proved that Cd pollution can cause damage to plant growth and physiological metabolism (Shahid et al. 2017). Toxic effect of Cd is related to its accumulation from plant roots, where Cd ions are absorbed, enter into cells, and cause damage to cells (Belimov et al. 2003; Sebastian and Prasad 2014; Verbruggen et al. 2009). There are many researches on the distribution and chemical forms of Cd in hyperaccumulators and some crops (Guo et al. 2018; Liao et al. 2004; Wang et al. 2009; Weigel and Juger 1980; Xin et al. 2013; Xu et al. 1991). It has been reported that the biological activity of Cd in plants is associated with its subcellular distribution and chemical forms, both of them are closely related to the level of free Cd ions in plant cells and are not only species-specific but also cultivar-dependent. The different strategies of Cd distribution and chemical form adopt in plants influence the migration and accumulation of Cd (Wang et al. 2009; Zhang et al. 2009). The variation among different cultivars within the same species is a key factor involved in the mechanisms of the cultivar-dependent Cd accumulation and thus is valuable to be investigated (Martin et al. 2012; Qiu et al. 2011; Wang et al. 2007).