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. 1993 Dec;103(4):1089–1096. doi: 10.1104/pp.103.4.1089

Effect of Severe Water Stress on Aspects of Crassulacean Acid Metabolism in Xerosicyos.

B Bastide 1, D Sipes 1, J Hann 1, I P Ting 1
PMCID: PMC159093  PMID: 12232003

Abstract

Xerosicyos danguyi H.Humb. (Cucurbitaceae) is a Crassulacean acid metabolism (CAM) species native to Madagascar. Previously, it was shown that when grown under good water conditions, it is a typical CAM plant, but when water stressed, it shifts to a dampened form of CAM, termed CAM-idling, in which stomata are closed day and night but with a continued, low diurnal organic acid fluctuation. We have now studied the kinetics of some metabolic features of the shift from CAM to CAM-idling under severe water stress and the recovery upon rewatering. When water is withheld, there is a steady decrease in relative water content (RWC), reaching about 50%, at which point the water potential decreases precipitously from about -2 or -3 bars to -12 bars. Abscisic acid (ABA) increases sharply at about 75% RWC. Stomata close, which limits CO2 uptake, and there is a dampened diurnal organic acid fluctuation typical of CAM-idling. Throughout an extended stress period to 50% RWC, there is no change in chlorophyll, protein, and ribulose bisphosphate carboxylase activity compared with the well-watered plants. Despite the fact that the tissue was already in CAM, the stress is accompanied by an increase in phosphoenolpyruvate carboxylase (PEPc) mRNA, extractable PEPc activity, and PEPc protein (such that the specific activity remained approximately constant) and a decrease in the apparent Km(PEP). It is not known if the changes in Km(PEP) in response to drought are related to or are separate from the increases in PEPc protein and mRNA. The changes in Km(PEP) could be in response to the decreased endogenous levels of organic acids, but evidently are not an assay artifact. The increases in PEPc protein and mRNA appear to be related to the water-stress treatment and may result from the increased concentration of ABA or the decreased levels of endogenous organic acids. When rewatered, the metabolism quickly returns to the well-watered control typical of CAM.

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Selected References

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  1. Arnon D. I. COPPER ENZYMES IN ISOLATED CHLOROPLASTS. POLYPHENOLOXIDASE IN BETA VULGARIS. Plant Physiol. 1949 Jan;24(1):1–15. doi: 10.1104/pp.24.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bandarian V., Poehner W. J., Grover S. D. Metabolite activation of crassulacean Acid metabolism and c(4) phosphoenolpyruvate carboxylase. Plant Physiol. 1992 Nov;100(3):1411–1416. doi: 10.1104/pp.100.3.1411. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
  4. Bray E. A., Beachy R. N. Regulation by ABA of beta-Conglycinin Expression in Cultured Developing Soybean Cotyledons. Plant Physiol. 1985 Nov;79(3):746–750. doi: 10.1104/pp.79.3.746. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Chu C., Dai Z., Ku M. S., Edwards G. E. Induction of Crassulacean Acid Metabolism in the Facultative Halophyte Mesembryanthemum crystallinum by Abscisic Acid. Plant Physiol. 1990 Jul;93(3):1253–1260. doi: 10.1104/pp.93.3.1253. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Guralnick L. J., Ting I. P. Physiological Changes in Portulacaria afra (L.) Jacq. during a Summer Drought and Rewatering. Plant Physiol. 1987 Oct;85(2):481–486. doi: 10.1104/pp.85.2.481. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Huerta A. J., Ting I. P. Effects of Various Levels of CO(2) on the Induction of Crassulacean Acid Metabolism in Portulacaria afra (L.) Jacq. Plant Physiol. 1988 Sep;88(1):183–188. doi: 10.1104/pp.88.1.183. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Jiao J. A., Chollet R. Posttranslational regulation of phosphoenolpyruvate carboxylase in c(4) and crassulacean Acid metabolism plants. Plant Physiol. 1991 Apr;95(4):981–985. doi: 10.1104/pp.95.4.981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Lorimer G. H., Badger M. R., Andrews T. J. D-Ribulose-1,5-bisphosphate carboxylase-oxygenase. Improved methods for the activation and assay of catalytic activities. Anal Biochem. 1977 Mar;78(1):66–75. doi: 10.1016/0003-2697(77)90009-4. [DOI] [PubMed] [Google Scholar]
  10. Patel A., Ting I. P. Relationship between Respiration and CAM-Cycling in Peperomia camptotricha. Plant Physiol. 1987 Jul;84(3):640–642. doi: 10.1104/pp.84.3.640. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Rayder L., Ting I. P. Shifts in the Carbon Metabolism of Xerosicyos danguyi H. Humb. (Cucurbitaceae) Brought About by Water Stress : I. General Characteristics. Plant Physiol. 1983 Jul;72(3):606–610. doi: 10.1104/pp.72.3.606. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Rayder L., Ting I. P. Shifts in the Carbon Metabolism of Xerosicyos danguyi H. Humb. (Cucurbitaceae) Brought About by Water Stress : II. Enzymology. Plant Physiol. 1983 Jul;72(3):611–615. doi: 10.1104/pp.72.3.611. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Szarek S. R., Johnson H. B., Ting I. P. Drought Adaptation in Opuntia basilaris: Significance of Recycling Carbon through Crassulacean Acid Metabolism. Plant Physiol. 1973 Dec;52(6):539–541. doi: 10.1104/pp.52.6.539. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Winter K. Day/Night Changes in the Sensitivity of Phosphoenolpyruvate Carboxylase to Malate during Crassulacean Acid Metabolism. Plant Physiol. 1980 May;65(5):792–796. doi: 10.1104/pp.65.5.792. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Wu M. X., Wedding R. T. Regulation of phosphoenolpyruvate carboxylase from Crassula by interconversion of oligomeric forms. Arch Biochem Biophys. 1985 Aug 1;240(2):655–662. doi: 10.1016/0003-9861(85)90073-6. [DOI] [PubMed] [Google Scholar]

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