Response of barley plants to Fe deficiency and Cd contamination as affected by S starvation

Abstract

Both Fe deficiency and Cd exposure induce rapid changes in the S nutritional requirement of plants. The aim of this work was to characterize the strategies adopted by plants to cope with both Fe deficiency (release of phytosiderophores) and Cd contamination [production of glutathione (GSH) and phytochelatins] when grown under conditions of limited S supply. Experiments were performed in hydroponics, using barley plants grown under S sufficiency (1.2 mM sulphate) and S deficiency (0 mM sulphate), with or without Fe(III)-EDTA at 0.08 mM for 11 d and subsequently exposed to 0.05 mM Cd for 24 h or 72 h. In S-sufficient plants, Fe deficiency enhanced both root and shoot Cd concentrations and increased GSH and phytochelatin levels. In S-deficient plants, Fe starvation caused a slight increase in Cd concentration, but this change was accompanied neither by an increase in GSH nor by an accumulation of phytochelatins. Release of phytosiderophores, only detectable in Fe-deficient plants, was strongly decreased by S deficiency and further reduced after Cd treatment. In roots Cd exposure increased the expression of the high affinity sulphate transporter gene (HvST1) regardless of the S supply, and the expression of the Fe deficiency-responsive genes, HvYS1 and HvIDS2, irrespective of Fe supply. In conclusion, adequate S availability is necessary to cope with Fe deficiency and Cd toxicity in barley plants. Moreover, it appears that in Fe-deficient plants grown in the presence of Cd with limited S supply, sulphur may be preferentially employed in the pathway for biosynthesis of phytosiderophores, rather than for phytochelatin production.

Ethylene Potentiates Sulfur-Mediated Reversal of Cadmium Inhibited Photosynthetic Responses in Mustard

“…Application of S or ethylene minimized H 2 O 2 and TBARS content, but the decrease was more prominent when ethylene and S were applied together to Cd grown plants ( Table 1 ) apparently because of enhanced S-assimilation capacity of plants. This finding is in agreement with the earlier studies in which S reduced oxidative stress in B. campestris (Anjum et al, 2008), Triticum aestivum (Gaafar et al, 2012), H. vulgare (Astolfi et al, 2012), and A. thaliana (Bashir et al, 2013) under Cd stress. Role of ethylene has been found to reduce oxidative stress in B. juncea (Masood et al, 2012b; Asgher et al, 2014; Khan and Khan, 2014).…”

Fe modulates Cd-induced oxidative stress and the expression of stress responsive proteins in the nodules of Vigna radiata

“…1b). These results were consistent with previous results of barley roots under S and Fe deficiency in relation to Cd-exposure (Astolfi et al 2012). Cd-exposure reduced significantly leaf, root length, chlorophyll content of host plant, also decreased the number and biomass of nodules (Table 1).…”

Heavy metal toxicity in rice and soybean plants cultivated in contaminated soil

“…Cadmium is also responsible for absorption sites in the plasma membrane with Fe, causing Fe deficiency symptoms (Gallego et al, 1996;Siedlecka & Krupa, 1999; Astolfi et al, 2012). High Mn concentrations may reduce Fe absorption and induce deficiency.…”