Cadmium-induced changes in antioxidant enzyme activities in rice (Oryza sativa L. cv. Dongjin)

Abstract

We studied how the relationship between cadmium (Cd) toxicity and oxidative stress influenced the Brm~th, photo.. synthetic efficiency, lipid peroxidation, and activity of ntimddative enzymes in the roots and leaves of rice (Oryza sat/va L Don~in). Plants were exposed to Cd for 21 d. Both seedling growth and photosynthetic efficiency decreased 8radu-ally with increasin 8 cadmium concentrations. Upid peroxi~ increased slowly in both roots and leaves, causing oxidative stress. However, each tissue type responded differentJy to Cd concentrations with regard to the induction/ inhibition of antioxidative enzymes. The acti~/of superoxide dismutase (SOD) increased in both roots and leaves. Ascorbate peroxidase (APX) activity increased in leaves treated with up to 0~5 I~l Cd, then decreased 8radually at higher concentrations. In contrast, APX activity in roots increased and remained constant between 0.25 and 25 pM Cd. Enhanced peroxidase (POD) activity was recorded for treatments with up to 25 ~ Cd, 8radually decreasing at higher concentrations in the leaves but remaining unchan~d in the roots. Catalase (CAT) activity increased in the roots, but decreased in the leaves, whereas the activity of 81utathione reductase (GR) was enhanced in both roots and leaves, where it remained elevated at higher Cd concentrations. These results susBest that.rice seedlinss tend to cope with free radicals bqmerated by Cd throush coordinated, enhanced activities of the antioxidative enzymes involved in detoxification.

Oxidative stress and phytochelatin characterisation in bread wheat exposed to cadmium excess

“…1). Decrease in growth and in FW or DW was also reported in Cd-treated plants of wheat, barley (Hordeum vulgare L.) and rice (Oryza sativa L.) [2,36,38,43]. Particularly in wheat plants, addition of Cd to the nutrient solution decreased shoot and root weight and length, with a growth inhibition varying between roots and shoots and among genotypes [47].…”

“…Both increase and decrease in the activity of many antioxidant enzymes has been observed in Cd-treated plants [2,13,26,33], suggesting that the antioxidant systems, beside being involved in detoxification process, could be sensitive targets of Cd toxicity.…”

Responses of Photosynthetic Efficiency and Ascorbate Peroxidase Induced by Salt Stress in Rice (Oryza sativa L.)

“…We previously showed that reduction in Fv/Fm ratio (Fig. 1A), was related to oxidative stress [1,32], but which was not related to chilling and drought stresses (Fig. 1B).…”

Changes of Essential Mineral Elements Contents in Response to Cu<sup>2+</sup> Treatment in <i>Sagittaria sagittifolia</i>

“…In addition to causing accumulation of toxic metals, heavy metal stress can also affect the absorption of essential mineral elements in plants, and different kinds of heavy metals exert different effects on absorption of mineral elements in different plants [11]. This study found that the Cu 2+ treatment not only inhibited the absorption of P, K, Ca, Mg by S. sagittifolia roots to different degrees (Figure 1), but also made P, K and Mg transport to leaves excessively, which eventually caused contents of P, K and Mg in leaves higher than those in the roots, while Ca content in leaves was lower than that in roots (Figure 2).…”