Antioxidant Enzymes Regulate Reactive Oxygen Species during Pod Elongation in Pisum sativum and Brassica chinensis

Abstract

Previous research has focused on the involvement of reactive oxygen species (ROS) in cell wall loosening and cell extension in plant vegetative growth, but few studies have investigated ROS functions specifically in plant reproductive organs. In this study, ROS levels and antioxidant enzyme activities were assessed in Pisum sativum and Brassica chinensis pods at five developmental stages. In juvenile pods, the high levels of O2 .− and.OH indicates that they had functions in cell wall loosening and cell elongation. In later developmental stages, high levels of.OH were also related to increases in cell wall thickness in lignified tissues. Throughout pod development, most of the O2 .− was detected on plasma membranes of parenchyma cells and outer epidermis cells of the mesocarp, while most of the H2O2 was detected on plasma membranes of most cells throughout the mesocarp. This suggests that these sites are presumably the locations of ROS generation. The antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) apparently contributed to ROS accumulation in pod wall tissues. Furthermore, specifically SOD and POD were found to be associated with pod growth through the regulation of ROS generation and transformation. Throughout pod development, O2 .− decreases were associated with increased SOD activity, while changes in H2O2 accumulation were associated with changes in CAT and POD activities. Additionally, high POD activity may contribute to the generation of.OH in the early development of pods. It is concluded that the ROS are produced in different sites of plasma membranes with the regulation of antioxidant enzymes, and that substantial ROS generation and accumulation are evident in cell elongation and cell wall loosening in pod wall cells.

Micropilar and embryonic events during hydration of Melanoxylon brauna Schott seeds

“…Considering that the production of ROS occurs during seed formation due to the synthesis metabolism (Liu et al, 2014), catalase activity would act to reduce the level of these substances during germination so they do not cause damage to the cells, but keeping them in a concentration that would act in the wall flexibility. Thus, hydration occurring in phase I would be possible by the Fenton reaction.…”

Signaling pathway in development of Camellia oleifera nurse seedling grafting union

“…Germin-like proteins can bind carbohydrates such as cellulose to participate in cell wall modification, and, on the other hand, can prevent cell growth through negative (Dunwell et al 2008;Caliskan et al 2004), which can be cleared by SOD and CAT (Liu et al 2014a). Therefore, reducing SOD and CAT activities result in H 2 O 2 increase, which can decrease OSBP activity to reduce cells proliferation and can increase ABA level to activate the MAPK signaling pathway for cells differentiation (Wang et al 2005).…”

Effects of Thallium Stress on Photosynthesis, Chlorophyll Fluorescence Parameters and Antioxidant Enzymes Activities of Coix Lacryma-jobi

“…3). In general, antioxidant enzymes are the common means in plants to regulate the ROS produced during metabolic processes [27]. Authors One possible reason is that Tl stress reduces the capacity of C. lacryma-jobi to assimilate carbon, thereby triggering an increase in photosynthetic electron flux to molecular oxygen, resulting in increased production of superoxide, namely hydrogen peroxide [28].…”