Crassulacean acid metabolism

Steudle, E., Smith, J.A.C. Liittge, U. (1980). Water relations parameters of individual mesophyll cells of the crassulacean acid metabolism plant Kalanchoe diagre-montiana. Plant Physiology, 66, 1155-63. 

The example we will consider in more detail is that of inducible CAM (Crassulacean acid metabolism). CAM is a modification of photosynthesis... 

Hofner, R., Vazquez-Morena, L., Winter, K., Bohnert, H.J. Schmitt, J.M. (1987). Induction of Crassulacean acid metabolism in Mesembryanthemum crystallinum by high salinity mass increase and de novo synthesis of PEP-carboxylase. Plant Physiology, 83, 915-19. 

Hokum, J.A.M. Winter, K. (1982). Activity of enzymes of carbon metabolism during the induction of Crassulacean acid metabolism in Mesembryanthemum crystallinum L. Planta, 155, 8-16. 

Ting, I.P. (1985). Crassulacean Acid Metabolism. Annual Review of Plant Physiology, 36, 595-622. 

An intriguing stress-induced alteration in gene expression occurs in a succulent plant, Mesembryanthemum crystallinum, which switches its primary photosynthetic CO2 fixation pathway from C3 type to CAM (Crassulacean acid metabolism) type upon salt or drought stress (Winter, 1974 Chapter 8). Ostrem et al. (1987) have shown that the pathway switching involves an increase in the level of mRNA encoding phosphoenol-pyruvate carboxylase, a key enzyme in CAM photosynthesis. 

CAM plants Abbreviation for crassulacean acid metabolism plants. cambium The layer of cells between the phloem and the wood of a tree, cameo A small relief carving on a different colored background, made from either onyx or two-color layered glass. 

Vacuoles (70-78) are membrane-bound regions of the cell filled with cell sap. Vacuoles are surrounded by a tonoplast (vacuolar membranes) and are diverse with distinct functions. Most investigators believe that lysosomes and the plant vacuoles are the same. Vacuoles develop turgor pressure and maintain tissue rigidity. They are storage components for various metabolites such as reserve proteins in seeds and malic acid in crassulacean acid metabolism (CAM) plants. Vacuoles canremove toxic secondary products and are the sites of pigment deposition. 

Szarek, S.R. and Troughton, J.H. (1976). Carbon isotope ratios in crassulacean acid metabolism. Plant Physiology 58 367-370. 

CAM (Crassulacean Acid Metabolism) photosynthetic pathway A variant of the C4 pathway phosphoenolpyruvate fixes C02 in C4 compounds at night, and then, the fixed C02 is transferred to the ribulose bisphosphate of the Calvin cycle within the same cell during the day. Characteristic of most succulent plants, such as cacti. 

Figure 23-39 A proposed night-day cycle of crassulacean acid metabolism.

Winter, K., and Smith, J. A. C., eds. (1996) Crassulacean Acid Metabolism Biochemistry, Ecophysiology and Evolution, Springer, Berlin... 

Brulfert, J., Guerrier, D. Queiroz, O. (1982). Photoperiodism and crassulacean acid metabolism. Planta 154, 332-8. 

Chu, C., Dai, Z., Ku, M.S.B. Edwards, G.E. (1990). Induction of crassulacean acid metabolism in the facultative halophyte Mesem-bryanthemum crystallinum by abscisic acid. Plant Physiology 93, 1253-60. 

Cockbum, W. (1981). The evolutionary relationship between stomatal mechanism, crassulacean acid metabolism and C4 photosynthesis. Plant, Cell and Environment 4, 417-18. 

Cushman, J.C., Michalowski, C.B. Bohnert, H.J. (19906). Developmental control of crassulacean acid metabolism inducibility by salt stress in the common ice plant. Plant Physiology 94, 1137-42. 

Heun, A.-M., Gorham, J., Liittge, U. Wyn Jones, R.G. (1981). Changes in water-relation characteristics and levels of organic cytoplasmic solutes during salinity induced transition of M. crystallinum from Q-photosynthesis to crassulacean acid metabolism. Oecologia 50, 66-72. 

Kluge, M. Ting, I.P. (1978). Crassulacean acid metabolism - analysis of an ecological adaptation. Ecological Studies, Vol. 30. Heidelberg Springer-Verlag. 

Winter, K. (1982). Regulation of PEP Carboxylase in CAM plants. In Crassulacean Acid Metabolism, ed. I.P. Ting M. Gibbs, pp. 153-69. Rockville, MD American Society of Plant Physiologists. 

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