Báo cáo lâm nghiệp: " Factors modulating superoxide dismutase activity in needles of spruce trees (Picea abies L.)"

Chia sẻ: Nguyễn Minh Thắng | Ngày: | Loại File: PDF | Số trang:4

Thêm vào BST

Báo xấu

52
lượt xem 1
download

Download Vui lòng tải xuống để xem tài liệu đầy đủ

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Factors modulating superoxide dismutase activity in needles of spruce trees (Picea abies L.)...

Chủ đề:

Bình luận(0) Đăng nhập để gửi bình luận!

Lưu

Nội dung Text: Báo cáo lâm nghiệp: " Factors modulating superoxide dismutase activity in needles of spruce trees (Picea abies L.)"

Factors modulating superoxide dismutase activity in needles of spruce trees (Picea abies L.) 2 B. Krings A. Polle’ 1 Rennenberg H. 1 Umweltforschung, Kreuzeckbahnstr. 19, Fraunhofer /nstitut für Atm. D-8100 Garmisch-Partenkir- chen, and 2 Botanisches Institut der Universitat zu Koln, Gyrhofstr. 15, D-5000 Kbin 41, F.R.G. the field. Extracts of spruce needles were pre- Introduction pared as described elsewhere (Polle et al., 1989). After dialysis, the activity of superoxide Superoxide dismutases (SOD) are consid- dismutase was determined according to the ered to be a major enzymic defense method of Misra and Fridovich (1972). This assay is based on the autooxidation of epine- against oxygen toxicity in cells (Fridovich, phrine to adrenochrome at pH 10.2. 0! serves 1986). These enzymes contain either as the chain-propagating species in this reac- Cu/Zn, Mn or Fe in their catalytic center tion. SOD competes for 0 thus inhibiting , 2 (Fridovich, 1986). Most abundant in plants adrenochrome formation. By definition, 1 unit of Cu/Zn-SODs which characterized SOD is the amount of extract that inhibits the are are maximal rate of adrenochrome formation by by a broad pH-optimum between pH 7 and 50%. pH 10 and an inhibition by cyanide and H (Fridovich, 1986). SODs detoxify 0 2 superoxide radicals originating from phy- siological functions, such as photosynthe- Results sis under excess light energy (Robinson, 1988), as well as different environmental herbicides and air stress factors, such To determine SOD activity, we adapted as pollutants (0 S0 N0 (Rabinowitch ,,) 322 extraction and assaying procedures (after and Fridovich, 1983; Fridovich, 1986). Misra and Fridovich, 1972) to extracts Since it is generally assumed that air pollu- from spruce needles (Polle et al., 1989). tion is one of the major reasons for forest Fig. 1 shows a typical calibration curve for decline in Central Europe, we compared spruce SOD. Increasing amounts of SOD activity in needles of healthy and in- spruce extract exhibited increasing inhibi- jured spruce trees growing in the field. tion of adrenochrome formation with a saturation level of 80%. In comparison with spruce extract, a commercially avail- able SOD preparation from horseradish Materials and Methods reached a saturation level of 90% in this assay system (not shown). The failure to Experiments were performed with needles from obtain complete inhibition was attributed Norway spruce trees (Picea abies L.) growing in
to alternative oxidative In needles from healthy trees, SOD ac- pathways (Misra in the youngest needles and Fridovich, 1972; Fridovich, 1986). highest tivity was and then declined by about 25% in 4 yr possibly caused by interactions with other old needles. In needles from injured trees, components present in crude dialyzed an enhanced level of SOD activity was spruce extracts. maintained through the 4 needle genera- In the presence of cyanide (20 pM tions studied. NaCN), the inhibition of adrenochrome for- mation was completely blocked (not shown). This observation indicates that predominately Cu/Zn-containing SOD- Discussion species contributed to the activity deter- mined with the epinephrine assay. Enhanced activity of superoxide dismu- It has been reported for other plants that tase in younger leaves has previously the activity of SOD is dependent upon the been reported in several plant species developmental stage of the tissue ana- (Rabinowitch a.nd Fridovich, 1983) and lyzed (Rabinowitch and Fridovich, 1983). was accompanied by an enhanced toler- However, data on developmentally deter- ance against SO (Tanaka and Sugahara, mined changes in SOD activity in needles 1980). Furthermore, higher SOD activities of conifers have not been published. found in conifer needles after were ozone Therefore, the activity of SOD was analyz- fumigation (Castillo et al., 1987) or if the ed in 4 subsequent generations of needles trees were growing in S0 -polluted 2 of healthy trees and compared with the regions (Huttunen and Heiska, 1988). We activity in needles of injured trees with observed in healthy needles of spruce 50% loss of needles. in the field that SOD activity growing trees
showed a maximum in the youngest gering mechanisms, such as, perhaps, air needles and then declined. In young pollution, play a major role in the regula- needles of severely injured trees, the SOD tion of SOD activity. activity was slightly enhanced as com- pared to SOD activity in needles from healthy trees. This high level of SOD Acknowledgments activity was maintained in the 4 needle generations analyzed. This result sug- We thank Beate Huber and Monika Braun for gests, that among other factors, SOD ac- expert technical assistance and acknowledge tivity in young needles is determined by financial support from the Bundesminister fur intrinsic developmental factors, while in Forschung und Technologie under contract no. older needles, external environmental trig- 0339019B7.
assay for superoxide dis- References and phrine simple a mutase. J. BioL Cibem. 247, 3170-3175 Polle A., Krings B. & Rennenberg H. (1989) Superoxide dismutase activity in needles of Castillo F.J., Miller P.R. & Greppin H. (1987) Norwegian spruce; trees (Picea abies L.). Plant Waldsterben Part IV. Extracellular biochemical 6 Physiol. 90, 1310-1316 markers of photochemical oxidant air pollution damage to Norway spruce. Experientia 43, 111- Rabinowitch H.D. & Fridovich 1. (1983) Super- 1155 oxide radicals, superoxide dismutases and oxy- gen toxicity in plants. Photochem. Photobiol. Fridovich 1. (1986) Superoxide dismutases. 37, 679-690 Adv. Enzymol. 58, 61-97 Robinson J.M. (1988) Does 0 photoreduction 2 Huttunen S. & Heiska E. (1988) Superoxide dis- within chloroplasts in vivo? Physiol. occur mutase activity in Scots pine (Pinus sylvestris Plant. 72, 666-680 L.) and Norway spruce (Picea abies L.) needles Tanaka K. & Sugahara K. (1980) Role of super- in northern Finland. Eur. J. For. Pathol. 18, 343- oxide dismutase in defense against S0 toxicity 2 350 and an increase in superoxide dismutase activi- Misra H.P. & Fridovich 1. (1972) The role of ty with S0 fumigation. Plant Cell Physiol. 21, 2 anion in the autooxidation of epine- superoxide 601-611