Contrasting effects of accumulation and tolerance characteristics in Arabidopsis thaliana under Cr(III) and Cr(VI) stress

In this study, for the first time we investigated Cr(III) and Cr(VI) stress-induced physiological and biochemical responses in Arabidopsis thaliana . The capacity of A. thalian to accumulate Cr is closely related to the valence of chromium. Cr(VI) was more toxic than Cr(III) as indicated by chromium accumulation and growth inhibition. When the concentration of chromium is greater than 200μM, the root length and biomass of A. thaliana are reduced. But interestingly, Cr(III) at 200μM increased the root length and biomass of A. thaliana compared to the control. The transmission electron microscope shows that Cr(VI) can cause the chloroplasts damaged and the chlorophyll reduced more than Cr(III). The chloroplasts were filled the starch grains. An increase of lipid peroxidation in A. thaliana roots caused by Cr was measured, and this effect increases as the increasing Cr. It indicated that A. thaliana suffers from Cr-induced oxidative stress which resulted cell death in roots. To fight against oxidative stress, Ascorbate peroxidase and Glutathione reductase were activated by Cr in antioxidant defense. The inhibition of growth, the accumulation of chromium, the responses of antioxidant systems, and the ultra-morphological changes indicate that Cr(VI) was more toxic than Cr(III) .

A study on chromium accumulation in Labeo rohita in the river Yamuna ecosystem in Mathura-Agra region in Uttar Pradesh, India

The present study revealed the chromium toxicity and its health measures in L. rohita from the Yamuna river at Mathura- Agra region. Samples were taken in triplicate from both sites i.e. Vrindavan (Bihar ghat) and Agra (Renuka Ghat). The study was carried out on Four different organs (i.e. gills, muscles, liver, and kidney) of the fish sample. The sampling was done from Oct 2018 to January 2020. Chromium concentration in different organs of the fish was analyzed by Atomic absorption spectrophotometer(AAS). The average Cr concentration in gills was highest (9.64 mg/l) at the Mathura site followed byAgra sites (7.78 mg/l) for the month of April 2019. The concentration of Cr was highest in samples taken in the month of April 2019 and it was lowest in October 2018. The significantly high Cr concentration values were observed in the Mathura region than the Agra region for both seasons. In all samples, Cr concentration was above the standards stated by WHO except in the Kidney. In the present study, the bioaccumulation factor showed the chromium concentration in the tissues followed the order of gill > liver > muscle > kidney. HPI, MQI, and Pearson’s correlation coefficient analysis were also done in which HPI was observed very high and there was a positive correlation between all the samples. Keywords: Chromium, BCF, HPI, MQI, AAS, Fish Organs

The Effect of Some Soil Amendments (Manure and Biochar) on the Bioaccumulation Capacity of Hexavalent Chromium by Two Species of (Salicornia Persica) and (Salicornia Perspolitana) From Contaminated Soil

Heavy metals are among the most dangerous contaminants in the environment. Application of organic compounds and plant species with the ability to accumulate and stabilize heavy metal in their organs is the best option for remediation of these elements in the soil. Therefore, this study aimed to investigate the effects of manure and biochar on the accumulation of heavy metals by Salicornia species. Two species of Salicornia ,including S. persica and S. perspolitana, were cultivated outdoor in experimental pots. The effects of experimental treatments ,including hexavalent chromium concentrations, manure ,and biochar on the two studied species, were investigated. The results indicated a significant effect (P < 0.05) of biochar on the accumulation of heavy metals by two species ,S. persicaand S. perspolitana, so that chromium concentrations in the roots and shoots were 258 and 5.41 mg/kg, respectively. Also, chromium accumulations under manure treatments in the roots and shoots were 334.34 and 9.79 mg/kg, respectively. Plant dry weight and height for both species in manure treatment were higher than control and biochar treatments. S. persica showed higher growth than S. perspolitana species. The content of photosynthetic pigments in both S.persica and S. perspolitana species under biochar treatment was higher than control and manure treatments. In general, one can conclude that the accumulation of chromium in S. perspolitana was higher than in S. persica ,and the application of biochar and manure amendments could stabilize chromium in soil and reduce chromium accumulation in both S. persica and S. perspolitana species.