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Raven JA, Handley LL, Macfarlane JJ, McInroy S, McKenzie L, Richards JH, Samuelsson G. The role of CO 2 uptake by roots and CAM in acquisition of inorganic C by plants of the isoetid life-form: a review, with new data on Eriocaulon decangulare L. THE NEW PHYTOLOGIST 1988; 108:125-148. [PMID: 33874162 DOI: 10.1111/j.1469-8137.1988.tb03690.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The isoetid life-form was originally defined on morphological grounds; subsequent physiological investigations showed that all of the isoetids examined took up a large fraction of the inorganic C fixed in their leaves from the root medium under natural conditions, and that some of them carried out much of their assimilation of inorganic C via a CAM-like mechanism. Root-dominated uptake of inorganic C appeared to be unique to, and ubiquitous in, the isoetids. I However, a large capacity for CAM-like metabolism in submerged vascular plants is not universal in isoetids, nor is it restricted to this life-form, being also found in Crassulaa aquatica. The work described here shows that submerged specimens of the North American Eriocaulon decangulare have a high fraction of their dry weight in the root system, a trait characteristic of isoetids but uncommon in other submerged vascular plants. E. decangulare has vesicular-arbuscular mycorrhizas, as do other flowering plant isoetids hut not, generally, submerged Isoetes spp. Under conditions of natural supply of inorganic C, E. decangulare, like other isoetids, takes up most of its inorganic C through its roots. Uptake of inorganic C by both roots and shoots involves CO2 rather than HCO3 : photosynthesis at high external pH values does not exceed the rate of uncatalysed HCO3 - to CO2 conversion in the medium and there is no detectable extracellular carbonic anhydrase activity. Measurements of titratable acidity and of malate content of leaves sampled at dawn and at dusk showed that E. decangulare, growing and tested under either emersed or submersed conditions, did not exhibit CAM-like behaviour. CAM was also absent from three non-isoetid aquatic macrophytes (Amphibolic antarctica, Eeklonia radiata and Vallisneria spiralis) which were examined. E. decangulare thus resembles all other isoetids tested in acquiring much of its inorganic C via the root system. E. decangulare also resembles most of the isoetids which are not members of the Isoetaceae (e.g.) E. septangulare, Lobelia dortmanna and Subularia aquatica) but differs from submerged Isoetaceae and Littorella uniflora in lacking CAM. The ecological significance of uptake of CO2 via the roots and, where it occurs, of CAM in isoetids may be related to either inorganic C or, via improved N use efficiency, inorganic C as a limiting resource. The isoetid life-forms has evolved independently in at last five different families of vascular plants; it probably derived fairly immediately from terrestrial or amphibious ancestors with a similar rosette form. Emergent Isoetaceae with acquisition of CO2 via roots and CAM probably evolved from submerged isoetids. CONTENTS Summary 123 I. Introduction 126 II. Material and Methods 127 III. Results and Discussion 129 IV. Conclusions 142 Acknowledgements 142 References 143.
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Affiliation(s)
- John A Raven
- Department of Biological Sciences, Florida International University, Tamiami Campus, Miami, Florida 33176, U.S.A
- Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, Scotland, U.K
| | - Linda L Handley
- Department of Biological Sciences, Florida International University, Tamiami Campus, Miami, Florida 33176, U.S.A
- Drinking Water Research Center, Florida International University, Tamiami Campus, Miami, Florida 33176, U.S.A
- Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, Scotland, U.K
| | - Jeffrey J Macfarlane
- Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, Scotland, U.K
- Roseworthy Agricultural College, Roseworthy, S.A. 5371, Australia†
| | - Shona McInroy
- Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, Scotland, U.K
| | - Lewis McKenzie
- Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, Scotland, U.K
| | - Jennifer H Richards
- Department of Biological Sciences, Florida International University, Tamiami Campus, Miami, Florida 33176, U.S.A
| | - Goran Samuelsson
- Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, Scotland, U.K
- Department of Plant Physiology, University of Umea, S-91087 Umea, Sweden‡
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Winter K, Edwards GE, Holtum JA. Nocturnal Accumulation of Malic Acid Occurs in Mesophyll Tissue without Proton Transport to Epidermal Tissue in the Inducible Crassulacean Acid Metabolism Plant Mesembryanthemum crystallinum: EVIDENCE AGAINST A PREVIOUS HYPOTHESIS. PLANT PHYSIOLOGY 1981; 68:355-7. [PMID: 16661916 PMCID: PMC427490 DOI: 10.1104/pp.68.2.355] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The inducible Crassulacean acid metabolism plant, Mesembryanthemum crystallinum, accumulates malic acid, i.e. equivalent amounts of malate anions and protons in the mesophyll cells at night. Levels of malate and titratable acidity are low in the epidermal tissue and do not change significantly during the day/night cycle. This result is in contrast to a recent report (Bloom 1979 Plant Physiol 64: 919-923) that the synthesis of malic acid during dark CO(2) fixation is associated with an equivalent exchange of inorganic cations from epidermal tissue with protons in the mesophyll cells.
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Affiliation(s)
- K Winter
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
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Heun AM, Gorham J, L�ttge U, WynJones RG. Changes of water-relation characteristics and levels of organic cytoplasmic solutes during salinity induced transition of Mesembryanthemum crystallinum from C3-photosynthesis to crassulacean acid metabolism. Oecologia 1981; 50:66-72. [DOI: 10.1007/bf00378795] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/1981] [Indexed: 11/30/2022]
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Winter K. Carbon Dioxide and Water Vapor Exchange in the Crassulacean Acid Metabolism Plant Kalanchoë pinnáta during a Prolonged Light Period: METABOLIC AND STOMATAL CONTROL OF CARBON METABOLISM. PLANT PHYSIOLOGY 1980; 66:917-21. [PMID: 16661552 PMCID: PMC440752 DOI: 10.1104/pp.66.5.917] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Net CO(2) and water vapor exchange were studied in the Crassulacean acid metabolism plant Kalanchoë pinnáta during a normal 12-hour light/12-hour dark cycle and during a prolonged light period. Leaf temperature and leaf-air vapor pressure difference were kept constant at 20 C and 9 to 10 millibar. There was a 25% increase in the rate of CO(2) fixation during the first 6 hours prolonged light without change in stomatal conductance. This was associated with a decrease in the intracellular partial pressure of CO(2), a decrease in the stimulation of net CO(2) uptake by 2% O(2), and a decrease in the CO(2) compensation point from 45 to 0 microbar. In the normal light period after deacidification, leaves showed a normal light dependence of CO(2) uptake but, in prolonged light, CO(2) uptake was scarcely light-dependent. The increase in titratable acidity in prolonged light was similar to that in the dark.The results suggest a change from C(3) photosynthetic CO(2) fixation in the second part of the 12-hour light period to a mixed metabolism in prolonged light with both ribulose bisphosphate carboxylase and phosphoenolpyruvate carboxylase as primary carboxylating enzymes.
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Affiliation(s)
- K Winter
- Department of Environmental Biology, Research School of Biological Sciences, Australian National University, P.O. Box 475, Canberra City, A.C.T. 2601, Australia
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