Comparative study of Cd uptake and tolerance of two Italian ryegrass (Lolium multiflorum) cultivars.

Zhigang Fang,Qingsheng Cai,Laiqing Lou,Lei Yang,Zhubing Hu,Yufeng Wang,Zhenglan Tai

doi:10.7717/peerj.3621

Abstract

Cadmium (Cd) is one of the most toxic heavy metals and is difficult to be removed from contaminated soil and water. Italian ryegrass (Lolium multiflorum), as an energy crop, exhibits a valuable potential to develop Cd polluted sites due to its use as a biofuel rather than as food and forage. Previously, via a screening for Cd-tolerant ryegrass, the two most extreme cultivars (IdyII and Harukaze) with high and low Cd tolerance during seed germination, respectively, were selected. However, the underlying mechanism for Cd tolerance was not well investigated. In this study, we comparatively investigated the growth, physiological responses, and Cd uptake and translocation of IdyII and Harukaze when the seedlings were exposed to a Cd (0–100 μM) solution for 12 days. As expected, excess Cd inhibited seedling growth and was accompanied by an accumulation of malondialdehyde (MDA) and reduced photosynthetic pigments in both cultivars. The effects of Cd on the uptake and translocation of other nutrient elements (Zn, Fe, Mn and Mg) were dependent on Cd concentrations, cultivars, plant tissues and elements. Compared with Harukaze, IdyII exhibited better performance with less MDA and higher pigment content. Furthermore, IdyII was less efficient in Cd uptake and translocation compared to Harukaze, which might be explained by the higher non-protein thiols content in its roots. Taken together, our data indicate that IdyII is more tolerant than Harukaze, which partially resulted from the differences in Cd uptake and translocation.

Highlights

Heavy metal contamination in agricultural soil and water introduced by human activities poses a serious environment issue (Bonfranceschi, Flocco & Donati, 2009; Mwamba et al, 2016; Toth et al, 2016)
In view of the difficulty of a cleanup of Cd-contaminated soil by physical or chemical means, planting energy crops became a viable alternative for exploiting heavy metal contaminated land (Shi & Cai, 2009; How to cite this article Fang et al (2017), Comparative study of Cd uptake and tolerance of two Italian ryegrass (Lolium multiflorum) cultivars
The biomass, Cd uptake, translocation, accumulation, and physiology parameters of two Italian ryegrass cultivars were significantly affected by Cd treatments

Summary

Introduction

Heavy metal contamination in agricultural soil and water introduced by human activities poses a serious environment issue (Bonfranceschi, Flocco & Donati, 2009; Mwamba et al, 2016; Toth et al, 2016). Cadmium (Cd), known as a highly toxic and non-biodegradable pollutant, is taken up by plant roots and translocated to other parts (Nocito et al, 2011), threatening human health via food contamination and ecosystem safety (Agami & Mohamed, 2013). In view of the difficulty of a cleanup of Cd-contaminated soil by physical or chemical means, planting energy crops became a viable alternative for exploiting heavy metal contaminated land (Shi & Cai, 2009; How to cite this article Fang et al (2017), Comparative study of Cd uptake and tolerance of two Italian ryegrass (Lolium multiflorum) cultivars. Increasing efforts have been devoted to isolating a tolerant cultivar and dissecting the mechanisms underlying their tolerance

Methods

Results

Conclusion