Production of reactive oxygen species, impairment of photosynthetic function and dynamic changes in mitochondria are early events in cadmium‐induced cell death in Arabidopsis thaliana

Abstract

Background information. Cadmium (Cd) is a highly toxic heavy metal that causes changes in plant metabolism through inhibiting photosynthesis and respiration. The effects of Cd on the morphology and function of the chloroplast and mitochondria, as well as on the production and localization of ROS (reactive oxygen species), were studied at the single-cell level in Arabidopsis.Results. The present study showed that the morphology of chloroplasts changed after Cd treatment, and the photochemical efficiency dramatically declined prior to obvious morphological distortion in the chloroplasts. A quick burst of ROS was detected after Cd treatment. The ROS appeared first in the mitochondria and subsequently in the chloroplast. Simultaneously, the mitochondria clumped irregularly around the chloroplasts or aggregated in the cytoplasm, and the movement of mitochondria was concomitantly blocked. Furthermore, the production of ROS was decreased after pre-treatment with ascorbic acid or catalase, which prevented inhibition of photosynthesis, organelle changes and subsequent protoplast death. Our results suggest that the distribution and mobility of mitochondria, the morphology of chloroplasts and the accumulation of ROS play important roles in Cd-induced cell death. The results are in good agreement with previous reports of many types of apoptotic-like cell death.Conclusion. The changes in the distribution and mobility of mitochondria, and morphology of chloroplasts, as well as the accumulation of ROS, play important roles in Cd-induced cell death.

Soil cadmium toxicity and nitrogen deposition differently affect growth and physiology in Toxicodendron vernicifluum seedlings

“…by LCd stress, which is consistent with previous observations (Kovácik et al 2006). However, in our study, the HCd induced increasing oxidative damage, as proposed also in previous studies (Lin et al 2007;Bi et al 2009). In addition, in the case of the HCd treatment, the combined LEN treatment increased the Cd content of leaves and shoot tissues.…”

“…The growth inhibition produced by Cd could be due to reductions of photosynthesis and chlorophyll content (Bi et al 2009), and it results in a decrease in biomass accumulation. When comparing N effect without Cd treatments in Table 1, total biomass was greater in LEN than in HEN, but no significant difference in leaf photosynthetic parameters was found.…”

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.…”

oiwa, a Female Gametophytic Mutant Impaired in a Mitochondrial Manganese-Superoxide Dismutase, Reveals Crucial Roles for Reactive Oxygen Species during Embryo Sac Development and Fertilization in Arabidopsis

“…5-(and 6)-Carboxy-29,79-dichlorodihydrofluorescein diacetate diffuses rapidly into the cells where it is hydrolyzed to 29,79-dichlorofluorescin (DCFH). Although it is generally accepted that DCFH is trapped in the cytosol where it is oxidized by a variety of ROS, preferentially hydrogen peroxide, to the highly fluorescent 29,79-dichlorofluorescein (DCF), colocalization of DCF fluorescence with mitochondria has also been reported (Zhang et al, 2009;Bi et al, 2012). As DCFH is rather insensitive to superoxide, DCF signal is generally correlated with peroxide levels (Royall and Ischiropoulos, 1993;Myhre et al, 2003).…”