Different Growth and Physiological Responses to Cadmium of the Three Miscanthus Species

Abstract

Miscanthus has been proposed as a promising crop for phytoremediation due to its high biomass yield and remarkable adaptability to different environments. However, little is known about the resistance of Miscanthus spp. to cadmium (Cd). To determine any differences in resistance of Miscanthus to Cd, we examined plant growth, net photosynthetic rate (Pn), activities of anti-oxidant and C4 photosynthetic enzymes, concentrations of Cd in leaves and roots, and observed the chloroplast structure in three Miscanthus species treated with 0, 10, 50, 100 or 200 μM Cd in solutions. Miscanthus sinensis showed more sensitivity to Cd, including sharp decreases in growth, Pn, PEPC activity and damage to chloroplast structure, and the highest H2O2 and Cd concentrations in leaves and roots after Cd treatments. Miscanthus sacchariflorus showed higher resistance to Cd and better growth, had the highest Pn and phosphoenolpyruvate carboxylase (PEPC) activities and integrative chloroplast structure and the lowest hydrogen peroxide (H2O2) and leaf and root Cd concentrations. The results could play an important role in understanding the mechanisms of Cd tolerance in plants and in application of phytoremediation.

Assessment of the adaptive and phytoremediation potential of Miscanthus×giganteus grown in flotation tailings

“…In this real-field experiment, M.×giganteus was shown to be capable of developing and growing in flotation tailings loaded with heavy metals. By far the largest portions of accumulated Pb, Cu and Zn were retained in the roots, which corresponded to data reported for different Miscanthus species grown on metal polluted substrates [29,[44][45][46]. Such pronounced retention of metals by the roots is due to their effective immobilization, mostly within the cell walls of the cortex parenchyma cells, and efficiently prevented transport toward the stele and aerial parts by the Casparian strip [47,48].…”

Pyrenoidal sequestration of cadmium impairs carbon dioxide fixation in a microalga

“…However, the algal PEP carboxylase activity is mainly anaplerotic and not photosynthetic (Giordano, Norici, Forssen, Eriksson, & Raven, ). Although the impact of cadmium on PEPC activity is not established in C. reinhardtii , it has been shown that Cd inhibits PEPC activity in higher plants like Miscanthus species (Guo et al, ) and Zea mays (Wang, Zhao, Liu, Zhou, & Jin, ).…”

The Alleviation of Nutrient Deficiency Symptoms in Changbai Larch (Larix olgensis) Seedlings by the Application of Exogenous Organic Acids

“…For example, SOD activities of Avicennia marina (a common mangrove species in South China) were decreased by Pb stress [32] and the activities of SOD decreased in Cd-treated L. olgensis leaves, possibly due to the binding of Cd to the thiol groups of the enzymes [21]. Previous studies have shown that spraying SA and other organic acids on tobacco [33], rice (Oryza sativa) [34], or perennial ryegrass [35] plants increases SOD activity. Similar responses in SOD activity were observed in maize leaves at six and then days after 1.0 mmol•L −1 SA treatment, where the copper couple superoxide dismutase (Sod4) transcription increased [36].…”

“…Chlorophyll is highly sensitive to stress and indicates the resistance of plants to stressed environments [41]. Environmental stress may harm the chloroplast structure of plants, inhibiting chlorophyll synthesis [35]. Carotenoid, a cell endogenous antioxidant, also plays an important role in scavenging reactive oxygen species and preventing membrane lipid peroxidation [40].…”