Crassulacean plants

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. 

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. 

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. 

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. 

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. 

Fahrendorf, T., Holtum, J. A. M., Muckerjee, U., and Latzko, E. 1987. Fructose 2,6-biphosphate. carbohydrate partitioning, and crassulacean acid metabolism. Plant Physiol. 84, 182-187. 

The central vacuole is a relatively simple aqueous phase that can act as a storage reservoir for metabolites or toxic products. For example, the nocturnal storage of organic acids, such as malic acid, takes place in the central vacuoles of Crassulacean acid metabolism plants (mentioned in Chapter 8, Section 8.5A), and certain secondary chemical products, such as phenolics, alkaloids, tannins, glucosides, and flavonoids (e.g., antho-cyanins), often accumulate in central vacuoles. Compared with the central vacuole, the cytoplasm is a more complex phase containing many colloids and membrane-bounded organelles. Because the central vacuole contains few colloidal or other interfaces, any matric pressure in it is... 

Figure 8-15. Carboxylase reactions and locations for the three photosynthetic pathways (a) C3, (b) C4, and (c) Crassulacean acid metabolism (CAM). The reactions for C3 and C4 plants occur during the daytime. The indicated decarboxylations of C4 acids occur in the cytosol of bundle sheath cells for C4 plants and the cytosol of mesophyll cells for CAM plants.

The electrical circuit in Figure 8-17 and Equations 8.30 and 8.31c developed from it are able to portray the CO2 compensation point, the light compensation point, as well as the general interrelations of the fluxes of CO2 for photosynthesis, photorespiration, and respiration in the light and in the dark. Our discussion and Figure 8-17 are for C3 plants—to apply an electrical circuit analog to C4 and Crassulacean acid metabolism (CAM)... 

Berger, M.G., Sprengart, M.L., Kusnan, M. and Fock, H.P. (1986) Ammonia fixation via glutamine synthetase and glutamate synthase in the crassulacean acid metabolism plant, Cissus quadrangularis. Plant Physiol., 81, 356-60. 

A few species of plants are capable of reducing carbon via either the C3 or Cl, pathway and are known as Crassulacean acid metabolism or CAM plants. As a result of tiieir photosynthetic flexibility, djeir 6 values most commonly range from approximately -12 to -27 %o (1<>). CAM plants are succulents, such as the cacti, and are seldom abundant or of economic importance. 

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