Variability in cadmium stress tolerance among four maize genotypes: Impacts on plant physiology, root morphology, and chloroplast microstructure

Cadmium (Cd) is detrimental to both plants and humans. Maize (Zea mays L.) genotypes exhibit variations in Cd accumulations. This study examined variations in Cd accumulation and tolerance among four maize genotypes with contrasting root morphology. The four maize genotypes were cultivated in a semi-hydroponic system with three Cd concentrations (0, 10, 20 μmol L-1). The effects of Cd on plant growth and physiology were assessed 39 days after transplanting. Results showed that root characteristics were positively correlated with root Cd accumulation and the bioconcentration factor under Cd20 treatment. Genotypes Shengrui999 and Zhengdan958 exhibited higher total Cd content than Xundan29 and Zhongke11 under Cd20 conditions. Cd toxicity led to membrane degradation of chloroplast mesophyll cells, loosening and swelling of grana lamella, and reduced starch reserves. The greater tolerance of Shengrui999 and Zhengdan958 was contributed to factors such as root biomass, shallower root depth, higher Cd content, accumulation of osmolyte such as soluble protein, antioxidant activities such as catalase (CAT), and the presence of phytohormone gibberellic acid. The study establishes a link between root morphology, Cd accumulation, and tolerance in maize plants, as demonstrated by the higher Cd accumulation and shallower root system in Cd-tolerant genotypes. This research provides a foundation for breeding maize cultivars better suited for adaptation to moderate Cd-contaminated environments.

Monitoring of surrogate zoonotic parasites of Anisakidae and Echinobothrium deeghai as bioindicators by application of energy dispersive X-ray microanalysis (EDXMA)

The unique characteristic of quickly altered but stable response by helminth parasites against metals and elements in a variety of aquatic ecosystems because of pollution conditions merit these as significant markers of fish health as well as of marine and freshwater ecosystems. Biomagnification of toxicants released in aquatic reservoirs by human mediated processes incorporating mining in coastal zones, industrial and agricultural inputs contributed to damaging consequences of human health due particularly to human consumption of edible fish and other biota that are exposed to contaminants in aquatic ecosystems. The metals and elements analysed could be arranged in decreasing order of concentration were found to be, P > Ca > Cd > Mn > Hg > Pb > As > Zn > S > Fe > Al > Cr > Mg > Cl. The association between Echinobothrium deeghai and Rotundocollarette capoori demonstrated surrogate relationship to drain in highly toxic heavy metals like Hg, Cr, As, Cd, from the ambience in the micro-environment of cestodes and nematodes and thus acted as benefactors for the life of the brackish water oceanodromous fish.

Carotid plaque instability is not related to quantity but to elemental composition of calcification

BACKGROUND AND AIMS

Recent studies highlighted the role of calcification processes in the clinical progression of chronic cardiovascular diseases. In this study we investigated the relationship between the chemical composition of calcification and atherosclerotic plaque stability in carotid arteries.

METHODS AND RESULTS

To this end, we characterized the calcification on 229 carotid plaques, by morphology, immunohistochemistry, transmission electron microscopy and energy dispersive X-ray microanalysis. Plaques were classified into two categories: unstable and stable. No significant differences were found in the incidence of the various risk factors between patients with and without carotid calcification, with the exception of diabetes. The energy dispersive X-ray microanalysis allowed us to identify two types of calcium salts in the atheromatous plaques, hydroxyapatite (HA) and calcium oxalate (CO). Our results showed that calcification is a common finding in carotid plaques, being present in 77.3% of cases, and the amount of calcium is not a factor of vulnerability. Noteworthy, we observed an association between HA calcification and unstable plaques. On the contrary, CO calcifications were mainly detected in stable plaques.

CONCLUSIONS

The presence of different types of calcification in atheromatous plaques may open new perspectives in understanding the molecular mechanisms of atheroma formation and plaque instability.

Cadmium (Cd) Localization in Tissues of Cotton (Gossypium hirsutum L.), and Its Phytoremediation Potential for Cd-Contaminated Soils

Phytoremediation using economically valuable, large biomass, non-edible plants is a promising method for metal-contaminated soils. This study investigated cotton's tolerance for Cd and remediation potential through analyzing Cd bioaccumulation and localization in plant organs under different soil Cd levels. Results showed cotton presents good tolerance when soil Cd concentration ≤20.26 mg kg(-1). Cotton had good Cd accumulation ability under low soil Cd levels (<1.26 mg kg(-1)), with a TF value (the ratio of Cd concentration in stem to root) above 1. Energy dispersive X-ray microanalysis indicated cotton leaf transpiration played a key role in extracting soil Cd, while roots and stems were the main compartments of Cd storage. Cd complexation to other organic constituents in root and stem cell sap could be a primary detoxifying strategy. Therefore, cotton is a potential candidate for phytoremediation of Cd-contaminated soils.