Cadmium uptake in Elodea canadensis leaves and its interference with extra‐ and intra‐cellular pH

Abstract

This study investigated cadmium (Cd) uptake in Elodea canadensis shoots under different photosynthetic conditions, and its effects on internal (cytosolic) and external pH. The plants were grown under photosynthetic (light) or non-photosynthetic (dark or in the presence of a photosynthetic inhibitor) conditions in the presence or absence of CdCl2 (0.5 μm) in a medium with a starting pH of 5.0. The pH-sensitive dye BCECF-AM was used to monitor cytosolic pH changes in the leaves. Cadmium uptake in protoplasts and leaves was detected with a Cd-specific fluorescent dye, Leadmium Green AM, and with atomic absorption spectrophotometry. During cultivation for 3 days without Cd, shoots of E. canadensis increased the pH of the surrounding water, irrespective of the photosynthetic conditions. This medium alkalisation was higher in the presence of CdCl2 . Moreover, the presence of Cd also increased the cation exchange capacity of the shoots. The total Cd uptake by E. canadensis shoots was independent of photosynthetic conditions. Protoplasts from plants exposed to 0.5 μm CdCl2 for 3 days did not exhibit significant change in cytosolic [Cd(2+)] or pH. However, exposure to CdCl2 for 7 days resulted in increased cytosolic [Cd(2+) ] as well as pH. The results suggest that E. canadensis subjected to a low CdCl2 concentration initially sequesters Cd into the apoplasm, but under prolonged exposure, Cd is transported into the cytosol and subsequently alters cytosolic pH. In contrast, addition of 10-50 μm CdCl2 directly to protoplasts resulted in immediate uptake of Cd into the cytosol.

Salix matsudana Koidz Tolerance Mechanisms to Cadmium: Uptake and Accumulation, Subcellular Distribution, and Chemical Forms

“…They can bind strongly to SH-containing enzymes/proteins inside the cell. Obviously, Leadmium Green AM dye has higher affinity for Cd than internal proteins [28] and is not sensitive to other divalent ions Values followed by different letters differ significantly from each other (P <0.05, t-test). Means ±SE, n = 4.…”

Role of Ferrous Sulfate (FeSO4) in Resistance to Cadmium Stress in Two Rice (Oryza sativa L.) Genotypes

“…Excess Cd decreased the Fe, Mg, and P contents in numerous plant species, which may cause ions deficiency in plants. It is well known that Cd toxicity in crops depends on the bioavailability of Cd in soils and the concentration of elements, which can compete with Cd during plant uptake [88]. In general, O. sativa takes up Cd in the form of Cd 2+ from the soils.…”

Cadmium localization and its toxic effects on root tips of barley

“…Cadmium ions can bind strongly to SHcontaining enzymes/proteins inside the cell. Leadmium TM Green AM dye has higher affinity for cadmium than internal proteins (Javed et al, 2014) and is not sensitive to other divalent ions except for lead. The uptake of cadmium into root cells of barley using the Cd-sensitive dye Leadmium TM Green AM was investigated.…”