Abstract
The activities of two key enzymes of the glyoxylic-acid cycle, isocitrate lyase and malate synthase, can barely be detected in mature, presenescent primary leaves of barley (Hordeum vulgare L.) but are apparently induced in senescent leaf tissue. Upon incubation of leaf segments in permanent darkness, the activities appear and increase dramatically up to the sixth day and thereafter decline. The glyoxylic-acid cycle may thus be functional during foliar senescence. The main period of galactolipid loss is characterized by RQ values as low as 0.63, indicating that long-chain fatty acids produced from thylakoidal acyl-lipids may be utilized for gluconeogenesis involving corresponding glyoxisomal metabolic pathways. Foliar senescence may be characterized by a peroxisomeglyoxysome transition analogous to the glyoxisome-peroxisome transition in greening cotyledons of fat-storing seeds.
Abbreviations
- FW:
-
fresh weight
- MGDG:
-
monogalactosyl diacylglycerol
- RQ:
-
respiratory quotient
References
Beevers, H. (1979) Microbodies in higher plants. Annu. Rev. Plant Physiol. 30, 159–193
Fong, F., Heath, R.L. (1977) Age dependent changes in phospholipids and galactolipids in primary bean leaves (Phaseolus vulgaris). Phytochemistry 16, 215–217
Gerbling, H., Gerhardt, B. (1987) Activation of fatty acids by non-glyoxysomal peroxisomes. Planta 171, 386–392
Gerhardt, B. (1981) Enzyme activities of the β-oxidation pathway in spinach leaf peroxisomes. FEBS Lett. 126, 71–73
Gerhardt, B. (1983) Localization of β-oxidation enzymes in peroxisomes isolated from non fatty plant tissues. Planta 159, 238–246
Gerhardt, B. (1986) Basic metabolic function of the higher plant peroxisome. Physiol. Vég. 24, 397–410
Harwood, J.L., Jones, A.V.H.M., Thomas, H. (1982) Leaf senescence in a non-yellowing mutant of Festuca pratensis. III. Total acyl lipids of leaf tissue during senescence. Planta 156, 152–157
Hock, B., Beevers, H. (1966) Development and decline of the glyoxylate cycle enzymes in watermelon seedlings (Citrullus vulgaris Schrad.). Effects of dactinomycin and cycloheximide. Z. Pflanzenphysiol. 55, 405–414
James, W.O. (1953) Plant respiration. Clarendon Press, Oxford
Kindl, H. (1987) β-Oxidation of fatty acids by specific organelles. In: The biochemistry of plants, vol. 9: Lipids: structure and function, pp. 31–52, Stumpf, P.K., ed. Academic Press, New York San Francisco London
Koiwai, A., Matsuzaki, T., Suzuki, F., Kawashima, N. (1981) Changes in total and polar lipids and their fatty acid composition in tobacco leaves during growth and senescence. Plant Cell Physiol. 22, 1059–1065
Laurière, Ch. (1983) Enzymes and leaf senescence. Physiol. Vég. 21, 1159–1177
Matile, Ph., Ginsburg, S., Schellenberg, M., Thomas, H. (1987) Catabolites of chlorophyll in senescent leaves. J. Plant Physiol. 129, 219–228
Veierskov, B. (1987) Irradiance-dependent senescence of isolated leaves. Physiol. Plant. 71, 316–320
Yemm, E.W. (1935) Respiration of barley leaves. II. Carbohydrate concentration and CO2 production in starving leaves. Proc. R. Soc. London Ser. B. 117, 504–525
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Gut, H., Matile, P. Apparent induction of key enzymes of the glyoxylic acid cycle in senescent barley leaves. Planta 176, 548–550 (1988). https://doi.org/10.1007/BF00397663
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DOI: https://doi.org/10.1007/BF00397663