Toxic Effects, Oxidative Stress and Ultrastructural Changes in Moss Taxithelium Nepalense (Schwaegr.) Broth. Under Chromium and Lead Phytotoxicity

Abstract

The effect of short-term Pb and Cr (0, 100 and 1000µM) stress in moss Taxithelium nepalense (Schwaegr.) Broth., the possible generation of oxidative stress, antioxidant metabolism and changes in the chloroplast and cell membrane ultrastructure were investigated. In moss cells, treatment of Pb and Cr for 12 and 24 h decreased the dry mass and total chlorophyll content with marked inhibition under Pb. Both Pb and Cr accumulated after 24 h of their treatment where highest accumulation of Pb was visible than that of Cr. The ultrastructural studies at 1000 µM of Pb and Cr showed distortion of the thylakoid, distortion of chloroplast membrane and changes in the chloroplast structure. Chloroplast distortion was highly visible under Pb than that of Cr. The distortion in the cell membrane was evident at high concentration of Pb, while under Cr, minor changes were visible as compared to controls. Both Pb and Cr significantly increased the production of ROS like H 2 O 2 and O − 2 radical with marked production after 24 h under Pb than that of Cr. The alteration in metabolism of activated oxygen in moss cells was evidenced by the increase in the lipid peroxidation in moss cells, with pronounced effect after 24 h than that of 12 h after Pb and Cr treatment. The SOD activity showed an increasing trend followed by decrease in CAT, POX and GR activity after 12 and 24 h. Both ascorbate and glutathione showed higher accumulation under Pb followed by Cr. The results showed that at high concentration of metals, oxidative stress could be induced in moss cells characterized by the generation of ROS and initiation lipid peroxidation that inhibited the major antioxidant metabolism. Both physiological and ultrastructural studies suggested the possible induction of oxidative stress in Taxithelium nepalense (Schwaegr.) Broth. under Pb and Cr toxicity.

Bioaccumulation and oxidative stress impact of Pb, Ni, Cu, and Cr heavy metals in two bryophyte species, Pleurochaete squarrosa and Timmiella barbuloides

“…Increase of ascorbate was induced in both moss species against ROS-generating metals Cu and Cr. Our data are in accordance with reports presenting Cu-and Crinduced ascorbate increase in alleviation of oxidative stress for mosses (Choudhury and Panda, 2005). In response to Cu and Cr, the GSH/GSSG ratio exhibits a trend similar to ascorbate.…”

“…Cu treatment induced SOD activity in P. squarrosa, but not in T. barbuloides. Increase in SOD activity was shown in moss species Fontinalis antipyretica under Cu exposure (Dazy et al, 2009) and in Taxithelium nepalense under Cr exposure (Choudhury and Panda, 2005). The opposite results of SOD activity in response to Cu and Cr between the two species could be due to possible differences in the redox status of cells.…”

Ultrastructural and Photosynthetic Response of Populus 107 Leaves to Cadmium Stress

“…Pietrini et al found that the peculiar Cd accumulation in small necrotic areas close to the main vein in willow and poplar clones is associated with [42]. Choudhury and Panda [43] and Bi et al [44] indicated that the alterations observed in the ultrastructure of the chloroplasts in leaves of plants exposed to Cd might be due to an increase in the production of reactive oxygen species (ROS), which in high concentration in the cellular environment can cause oxidative damage to cellular structure and function. The ultrastructural effects found in Populus 107 exposed to Cd, even at high concentrations and prolonged periods, are mainly confined to the chloroplasts structure.…”

Influence of heavy metals ions on growth and physiological and biochemical reactions of sand and water cultures of moss Drepanocladus aduncus (Hedw.) Warnst.

“…Проникаючи у клітини, іони важких металів негативно впливають на фізіологічні процеси і життєдіяльність рослин [27]. Результати аналізу інтенсивності люмінесценції хлорофілу у листках піщаних і водних культур моху D. аduncus в умовах інтоксикації Рb 2+ і Cd 2+ засвідчили її зниження, порівняно з контролем (рис.…”