A stress-induced oxidative burst in Eucheuma platycladum (Rhodophyta) |
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Authors: | Jonas Collén Marianne Pedersén C H Bornman |
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Institution: | Collén, J. and Pedersén, M. 1994. A stress-induced oxidative burst in Eucheuma platycladumt;(Rhodophyta). –Physiol. Plant. 92: 417–422. |
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Abstract: | A hurst of hydrogen peroxide has been found in the red macroalga Eucheuma platycladwn Schmitz as a response to mechanical stress. After exposure of pieces of thalli (2 cm) broken from the plant and stirred with a magnetic bar an oxidative burst was registered, as measured by luminol dependent chemiluminescence (LDC). The burst was totally inhibited by cataluse (EC 1.11.1.6). showing the generation of H2:O2; Ten g of seaweed in 300 ml sea water caused a maximal medium concentration of LDC corresponding to 7 u .M H2O2; The burst decayed after about 30 min. The decay is probably caused by increased catalase aciivity of the sea water. due to leakage of catalasc from the seaweed. Addition of NaN3 caused a dramatic increase in LDC. probably due to inhibition of catalase. Similar bursts of active oxygen, involving active oxygen species such as O2, H2O2 and OH. have been reported as pan of the hypcrsensitive reaction in some higher plants, e.g. tobacco. potato and soybean. Exposure of plants or cell suspension cultures to some pathogenic bacteria, fungi, inorganic elicitors or physical damage causes an oxidalive burst that is often followed by necrosis. The production ot active oxygen is thought to he a first defence against invading pathogens. We assume that the oxidative burst from E. platycladum is of a defensive nature, providing a protection against grazers and pathogenic organisms. To our knowledge this is the first repoil of an oxidalive burst from seaweeds. |
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Keywords: | Chemical defence Eucheuma H2O2 hypersensitive reaction oxidative burst |
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