Antioxidant Enzyme Activities Are Upregulated in Response to Cadmium in Sensitive, But Not in Tolerant, Rice (Oryza sativa L.) Seedlings

鎘所誘導之抗氧化酵素活性變化：耐鎘與不耐鎘水稻幼苗之比較

郭美君(Mei-Chun Kuo) ； 高景輝(Ching-Huei Kao)

《Botanical Bulletin of Academia Sinica》 45卷4期 (2004/10) Pp. 291-299

https://doi.org/10.7016/BBAS.200410.0291

摘要

本研究探討鎘處理對水稻兩個品種過氧化氫與malondialdehyde(MDA)含量以及抗氧化酵素活性變化之影響。氯化鎘處理增加不耐鎘品種台中在來一號(TN1)葉片之過氧化氫與MDA含量以及增加抗氧化酵素[superoxide dismutase (SOD), ascorbate peroxidase, glutathione reductase, catalase與peroxidase (POX)]之活性，但不影響耐鎘品種台農67號(TNG67)葉片過氧化氫與MDA含量以及抗氧化酵素之活性。氯化鎘處理之TN1葉片，其MDA含量與SOD及POX活性之增加早於毒害之發生。以離層酸前處理TN1幼苗，增加TN1對鎘的耐性，同時降低鎘所誘導之MDA含量與SOD及POX活性之增加。以離層酸合成抑制劑(fluridone)與鎘同時處理TNG67幼苗，可降低TNG67對鎘之耐性，增加MDA含量與SOD及POX之活性。同時，此種fluridone處理TNG67幼苗之效應又可被離層酸處理所恢復。本研究之結果似乎說明，氯化鎘TN1幼苗，其葉片可表現氧化逆境，然而鎘處理TNG67幼苗，其葉片不會表現氧化逆境，同時也說明鎘處理後TN1幼苗葉片所表現之鎘毒害是經由氧化逆境所造成。

關鍵字

離層酸 ； 鎘 ； 水稻 ； 氧化逆境

並列摘要

Changes in H2O2 and malondialdehyde (MDA) contents and antioxidant enzyme activities in Cd-treated rice (Oryza sativa L.) seedlings of two cultivars were investigated. On treatment with CdCl2, increases in H2O2 and MDA contents and antioxidant enzyme activities [speroxide dismutase (SOD), ascorbate peroxidase, glutathione reductase, catalase, and peroxidase (POX)] were observed in the leaves of Cd-sensitive cultivar (cv. Taichung Native 1, TN1) but not in Cd-tolerant cultivar (cv. Tainung 67, TNG67). The increased content of MDA and activities of SOD and POX preceded the occurrence of toxicity in CdCl2-treated TN1 leaves. Pretreatment with abscisic acid (ABA) enhanced Cd tolerance and reduced Cd-induced increase in the content of MDA and increase in the activities of SOD and POX in TN1 leaves. Exogenous application of ABA biosynthesis inhibitor, fluridone, decreased Cd tolerance, increased the content of MDA, and increased the activities of SOD and POX in Cd-treated TNG67 leaves. Furthermore, fluridone's effects on toxicity, the content of MDA, and the activities of SOD and POX in Cd-treated TNG67 leaves were reversed by the application of ABA. In conclusion, the oxidative stress is differently expressed in TN1 and TNG67 rice seedlings in response to CdCl2. Results also suggest that CdCl2 causes an oxidative stress and CdCl2-induced toxicity is mediated through oxidative stress in TN1 leaves.

並列關鍵字

Abscisic acid ； Cadmium ； Oryza sativa L. ； Oxidative stress