Báo cáo lâm nghiệp: "Light-quality and -quantity effects on monoterpene-mediated photo-bleaching of conifer needles"

Chia sẻ: Nguyễn Minh Thắng | Ngày: | Loại File: PDF | Số trang:3

Thêm vào BST

Báo xấu

60
lượt xem 5
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: Light-quality and -quantity effects on monoterpene-mediated photo-bleaching of conifer needles...

Chủ đề:

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

Lưu

Nội dung Text: Báo cáo lâm nghiệp: "Light-quality and -quantity effects on monoterpene-mediated photo-bleaching of conifer needles"

Light-quality and -quantity effects on monoterpene-medi- ated photo-bleaching of conifer needles J. Franzen K. Gross M. Bonzon 23 1 E. 1 Wagner Institutes of I Biology 11 and2 University of Freiburg i.Br., F.R.G., and Silviculture, 3 Institute of Plant Physiology University of Geneva (CH), Switzerland monoterpene-mediated changes of mem- Introduction branes. The result is a photooxidative bleaching of the chloroplast pigments. In earlier publications (Wagner et aL, In simulation experiments, we demon- 1987; Gross et al., 1988) we showed that strated such monoterpene effects (Gross monoterpenes, the characteristic products et al., 1988): fumigation of spruce (Picea of secondary metabolism in conifers, abies (L.) Karst.) seedlings and young could play a role in forest decline. plants with P-pinene resulted in a monoter- Monoterpenes are synthesized in leuco- pene concentration- and photofluency- plasts at the basis of needles and are dependent destruction of chloroplast pig- transported into resin ducts where they ments resembling the phenomenon of are kept strictly separated from the cyto- ’montane yellowing’. With the experiments plasm (Carde et al., 1980; Gleizes et al, presented here, we investigate the influen- 1983). In a working hypothesis (Wagner of light quality on monoterpene-medi- ce et al., 1987), we suggested that changes ated photo-bleaching of chloroplast pig- in membrane structure by air pollutants ments and on the levels of a-tocopherol. could liberate the monoterpenes from their storage compartments. In a kind of auto- catalytic fashion, the thus liberated mono- terpenes can induce further changes in Materials and Methods membrane structure which can influence the membrane-bound electron transport. In the various fumigation experiments, 3 mo old The inhibition of respiration and photosyn- spruce seedlings were incubated in glass ves- sels with 100 pl of /3-pinene per I of air. This thesis by the monoterpene /3-pinene had concentration of monoterpene is comparable to been demonstrated earlier (Douce et al., the levels stored in needles (see Sch6nwitz et 1978; Pauly et al., 1981The inhibition of al., 1987). In parallel to each fumigation experi- photosynthesis depends upon light inten- ment, a non-fumigated control was analyzed. sity and probably results from an overpro- Prior to the experimental treatments, the duction of oxygen free radicals due to seedlings had been cultivated in groups of 50
3:1 mixture of quartzsand and vermiculite adaptation (for review see Voskresenz- on a irrigated with tap water. Cultivation took place in kaya, 1988). glass vessels in continuous white light (16 W/ The incubators were placed for 48 h in ). 2 M In white light/dark cycles, chlorophyll b the various light environments in continuous and carotenoids were increased over the light or in 12:12 h cycles of light and dark at dark controls, while blue, red and far-red 298°K. After fumigation, 5 seedlings were com- light conditionsalso led to higher levels of bined for each sample and analyzed for their chlorophyll a. The increase in red light pigment content and a-tocopherol levels. Pigment determination was carried out in was less than in blue or in far-red light (cf. acetone according to Lichtenthaler (1987). To- Kasemir and Mohr, 1981).High intensity copherol was extracted in n-hexane and quanti- white light given in light/dark cycles did not fied by HPLC on a Lichrosorb Si 60.5 !column favor pigment accumulation, possibly indi- with n-hexane and 3% ethylacetate. cative of light ’stress’ (Wild, 1988), since seedlings were grown at lower light inten- sity prior to the experimental treatment. Results and Discussion Photodestruction of pigments primarily affected chlorophyll a. Accumulation of The results are summarized in Table I. b depended strongly upon chlorophyll The data on the non-fumigated seedlings membrane biogenesis. Grana develop- show - a light-dependent accumulation of ment in conifers was also stimulated by pigments, a well-known physiological far-red light (Tyskiewicz et al., 1979). Light
quality-dependent differences in chloro- References phyll b accumulation might result from differences in membrane biogenesis also Carde J.P., Bernard-Dagan C. & Gleizes M. dependent upon light quality. Earlier (1980) Membrane systems involved in synthe- screening experiments indicated an in- sis and transport of monoterpene hydrocarbons in pine leaves. In: Biogenesis and Function of crease in pigment content of chloroplasts Plant Lipids. (Mazliak P., Benveniste P., Costes after sublethal treatments with P-pinene in C. & Douce R., eds.), Biochemical Press, white light/dark cycles. Amsterdam, pp. 441-444 Depending upon light-quality, -quantity Douce R., Neuburger M., Bligny R. & Pauly G. (1978) Effects of /!pinene on the oxidative prop- and light/dark cycles, the fumigation with erties of purified intact plant mitochondria. In: /3-pinene modified pigment and a-tocophe- Plant Mitochondria. (Ducet G. & Lance C., eds.), rol levels (Table I). Fumigation with j3-pi- 4 Biochemical Press, Amsterdam, pp. 207-214 led to increase in chl b and in nene car an Gleizes M., Pauly G., Carde J.P., Marpeau A. & (D), (wUD), (rUD) and (bUD). However, in Bernard-Dagan C. (1983) Monoterpene hydro- (wL), (WUD) and (BL), P-pinene strongly carbon biosynthesis by isolated leucoplasts of reduced pigment levels. The increase of Citrofortunella mitis. Planta 159, 373-381 pigment content with P-pinene fumigation Gross K., Vollbrecht P., Franzen, J., Dietz J. & Wagner E. (1988) Untersuchungen zum mecha- might indicate the triggering of anti-oxidant nismus der neuartigen waldschäden: hemmung defense mechanisms. Reduction in pig- der photosynthese und vergilbung von fichten- ment content with j3-pinene fumigation keimlingen und -jungpflanzen durch begasung occurred under conditions of light ’stress’. mit P.pinen. Allg. Forst Jagdz. 159, 45-49 As shown earlier (Gross et al., 1988), this Kasemir H. & Mohr H. (1981) The involvement effect correlated positively with the j3- of phytochrome in controlling chlorophyll and 5- aminolevulinate formation in a gymnosperm pinene concentration. Fumigation with j3- seedling (Pinus sylvestris). Planta 152, 369 pinene reduced the level of a tocopherol Lichtenthaler H.K. (1987) Chlorophylls and in the dark controls (D). Low intensity of carotenoids: pigments of photosynthetic bio- white light (wL), red light (rUD, RL) and membranes. Methods Enzymol. 148, 350-382 far-red light (fr/D) increased a-tocopherol Pauly G., Douce R. & Carde J.P. (1981) Effects levels. Under conditions of j3-pinene- of /3-pinene on spinach chloroplast photosyn- mediated reduction of pigment contents, thesis. 1. PflanzenphysioL 104, 199-206 a-tocopherol levels were also strongly Sch6nwitz R., Merk L. & Ziegler A. (1987) Natu- reduced (wL, WUD). These results in- rally occurring monoterpenoids in needles of dicate differential modulation of a-toco- Picea abies L. Karst. Trees 1, 88-93 pherol synthesis and turnover by different Tyszkiewicz E., Nicolic D., Popovic R. & Saric photoreceptor systems and require further M. (1979) Photophosphorylation and ultrastruc- tural development in Pinus nigra chloroplasts, detailed investigations. grown under different spectral composition of light. Physiol. Plant. 46, 324-329 Voskresenzkaya N.P. (1988) Photoregulatory Acknowledgments reactions and activity of the photosynthetic apparatus. Sov. Plant Physiol. 34, 538-550 This work was supported by the Bundesmini- Wagner E., Vollbrecht P., Janistyn B., Gross K. sterium fOr Forschung und Technologie (con- & Woerth J. (1987) Monoterpen-vermittelte tract no. 0339214A4) and F. Hoffmann-La zerst6rung des photosyntheseapparates von Roche & Co. The responsibility for the contents umen. g waldb Allg. Forstz. 42, 705-708 rests with the authors. We are indebted to Mrs. Wild A. (1988) Licht als streBfaktor bei B. Rossi for her technical help with the determi- umen. g waldb Naturwiss. Rundsch. 41, 93-96 nation of tocopherol.