RESUMO
Experimental spinach plants grown in soil with (5, 10 and 20 ppm) arsenic (As) contamination were sampled in 21 days after As(V) contamination. Levels of As in spinach samples (from 0.31 ± 0.06 µg g-1 to 302.69 ± 11.83 µg g-1) were higher in roots and lower in leaves, which indicates a low ability of spinach to translocate As into leaves. Species of arsenic, As(III) and As(V), were represented in favor of the As (III) specie in contaminated variants, suggesting enzymatic arsenate reduction. In relation to predominant As accumulation in roots, changes in malondialdehyde levels were observed mainly in roots, where they decreased significantly with growing As contamination (from 11.97 ± 0.54 µg g-1 in control to 2.35 ± 0.43 µg g-1 in 20 ppm As). Higher values in roots than in leaves were observed in the case of 5-methylcytosine (5-mC). Despite that, a change in 5-mC by As contamination was further deepened in leaves (from 0.20 to 14.10%). In roots of spinach, expression of the CDC25 gene increased by the highest As contamination compared to the control. In the case of total phenolic content, total flavonoid content, total phenolic acids content and total antioxidant capacity were higher levels in leaves in all values, unlike the roots.
RESUMO
Arsenic represents a serious health threat in localities with a high arsenic-polluted environment and can easily get into the human food chain through agronomy production in areas affected by arsenic contamination. Onion plants that were grown in controlled conditions in arsenic-contaminated soil (5, 10, and 20 ppm) were harvested 21 days after contamination. Arsenic levels (from 0.43 ± 0.03 µg g-1 to 1761.11 ± 101.84 µg g-1) in the onion samples were high in the roots and low in the bulbs and leaves, which is probably caused by a reduced ability of the onions to transport arsenic from roots to bulbs and leaves. Arsenic species As(V) and As(III) in As(V)-contaminated soil samples were represented strongly in favor of the As(III) species. This indicates the presence of arsenate reductase. Levels of 5-methylcytosine (5-mC) (from 5.41 ± 0.28% to 21.17 ± 1.33%) in the onion samples were also higher in the roots than in the bulbs and leaves. Microscopic sections of the roots were examined, and the most damage was found in the 10 ppm As variant. Photosynthetic parameters pointed to a significant decrease in photosynthetic apparatus activity and the deterioration of the physiological state of plants as arsenic content increased in the soil.
RESUMO
Heavy metal stress is one of the major abiotic stresses that cause environmental pollution in recent decades. An elevated concentration of these heavy metals is highly toxic to plant. Chromium (Cr) is one of the heavy metals whose concentration in the environment is still increasing alarmingly. It is harmful for plant growth and achene yield. To check out the growth and protein alternation towards pollutants, two sunflower varieties (RA-713 and AHO-33) were subjected to different chromium concentrations (control, 200 ppm, 400 ppm) by soil application. This study has elaborated that 400 ppm Cr resulted in a reduction of various growth parameters. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to enhance the understanding of plant proteomic modulation under Cr stress. Different protein bands like 48 and 49, 26 kDa have newly appeared, and three 60, 47, and 42 kDa, and two protein bands 49 and 13 kDa were up-regulated in seeds of RA-713 and AHO-33, respectively. Some proteins (52, 16 kDa) are down-regulated in leaf tissues of both varieties. Only 6 and 81 kDa protein showed up-regulation and 154 kDa down-regulation behavior in the shoot in response to stress. The finding s of study might support the selection of tolerant genotype under Cr contamination and the discovery of new protein biomarkers that can use as monitoring tools in heavy metal stress biology.
