Chlorophyll as an indicator of the upper critical tissue concentration of cadmium in plants

Burton, K. W.; King, J. B.; Morgan, Edward A.

doi:10.1007/bf00464777

Cited by 31 publications

(21 citation statements)

References 8 publications

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“…Chlorophyll-a biosynthesis may be the most metal-sensitive enzyme system in plants ( Van Assche & Clijsters, 1990). It is directly degraded by Cd and other metals, causing chlorosis (Foy, Chaney & White, 1978), and was affected by lower Cd concentrations than those causing reduced root and shoot growth in wheat (Burton, King & Morgan, 1986). Chlorophyll-a content was successfully used to distinguish genotypic differences in the tolerances of Phalaris arutidinacea and Festuca arundinacea to various metals including Cd (Homer, Cotton & Fvans, 1980).…”

Section: Methodsmentioning

confidence: 99%

Induction of cadmium tolerance by acclimation transferred between ramets of the clonal fern Salvinia minima Baker

Outridge

Hutchinson

1991

New Phytologist

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SUMMARYChanges in the cadmium tolerance of 'daughter' ramets resulting from prior acclimation to Cd by 'parent' plants were examined in the clonal fern Salvinia minima Baker. In two experiments, parents were acclimated to 0, 10, 25 or 50^gCdl ', and subsequently produced daughter ramets in a Cd-free medium. Parent acclimation to 25 /ig Cd r' increased the daughter ramets' tolerance index by 13-17% (based on chlorophyll-a content), while 10//gCdl"' had no effect. Acclimation to 50/fg Cd T' produced 'carry-over' toxicity (i.e. reduced growth and chlorosis) in daughter ramets in Cd-free solution. Their tolerance index was 28 % higher than the control when tested with 15 /ig Cd T' in one experiment. In contrast, there was no such increase when they were tested with 25 /ig Cd 1 ' in a second experiment. This may be due to the higher Cd concentration in the latter test, combined with carry-over toxicity, overwhelming induced tolerance. 'Tolerant' daughter ramets, which maintained higher chlorophyll concentrations during Cd exposure than control ramets, also grew slower, a seeming contradiction. A possible explanation is that induced tolerance, involving protection of chlorophyll synthesis by phytochelatin binding with Cd, has an accompanying metabolic cost due to glutathione depletion. These data may be the first evidence of (a) induced metal tolerance in a vascular plant other than grasses, and (h) increased metal tolerance of daughter ramets due to acclimation of their parent clones. In patchily metalcontaminated habitats, the latter phenomenon may benefit rhizomatous clonal plants over non-integrated clones or annual plants. Daughter ramets connected to acclimated parents may be more likely to survive in other contaminated patches, increasing the possibility that the clone will grow into uncontaminated areas.

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Section: Methodsmentioning

confidence: 99%

Induction of cadmium tolerance by acclimation transferred between ramets of the clonal fern Salvinia minima Baker

Outridge

Hutchinson

1991

New Phytologist

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“…Metal concentrations used in these experiments were chosen from published work on critical metal concentrations in trees (Burton, King & Morgan, 1985;Turner & Dickinson, 1993) to represent a range from non-phytotoxic through to sub-lethal. The length of longest root, total number …”

Section: Short Term Cu Pre-treatmentmentioning

confidence: 99%

Acclimation of Salix to metal stress

1997

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SUMMARYNine different clones of six species of Salix (Salix cordata Muhlenb. non Michaux, 5. fragilis L., S. caprea L., S. cinerea h., S. burjatica Nazarov. and 5. viminalis L.) and one hybrid (S. x calodendron Wimm.) were exposed to heavy metals in solution culture in an attempt to increase innate metal resistance. Resistance was estimated using comparative root measurements, and metal uptake was also studied. The first experiment entailed pretreatments with background nutrient solution, or 0-25 and 050 mg Cu 1"^ amendments, and re-exposure to each of the same concentrations. In a second experiment clones were exposed to sub-toxic concentrations of single metals (0-15 mg Cu 1"', O-lSmgCdl"' or 2-5mgZnl'') and dual-combination treatments (0-075mgCu|-'-l-0-O75mgCdl-', O'O75 mg Cu 1"'+ 1 25 mg Zn I"' or 0'075 mg Cd 1"'+ 1-25 mg Zn 1" = )' with concentrations gradually raised 10-fold over 128 d. Plants tested in the first experiment, following pre-exposure to Cu, were no more resistant to subsequent exposure to this metal. In the second experiment, gradual cumulati^ e doses resulted in reduced phytotoxicity and increased resistance, most notably to Cd. There appeared to be an inverse relationship between metal uptake and resistance. Copper uptake was restricted to the roots, whereas Cd and Zn were more evenly distributed throughout the plant. Exposure to dual combinations of metals resulted in several interaction effects on uptake: increased root-bound Cu in all combinations, and the increase in uptake of both Cd and Zn into the root tissues when supplied with Cu. The implications of these results for the use of willows in phytoremediation programmes are discussed.

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“…Apart from retardation of plant growth, the most apparent symptom of Cd toxicity is chlorosis of the leaves. The latter phenomenon seems to be very closely related to the toxic action of Cd since the upper critical tissue concentration of Cd, above which yield is impaired, can be determined accurately by measuring the shoot chlorophyll level (Burton et al 1986). …”

Section: Introductionmentioning

confidence: 99%

Leaf chlorosis in oilseed rape plants ( Brassica napus ) grown on cadmium-polluted soil: causes and consequences for photosynthesis and growth

Baryla

Carrier

Franck

et al. 2001

Planta

337

178

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Brassica napus L. (oilseed rape) was grown from seeds on a reconstituted soil contaminated with cadmium (100 mg Cd kg-1 dry soil), resulting in a marked chlorosis of the leaves which was investigated using a combination of biochemical, biophysical and physiological methods. Spectroscopic and chromatographic analyses of the photosynthetic pigments indicated that chlorosis was not due to a direct interaction of Cd with the chlorophyll biosynthesis pathway. In addition, mineral deficiency and oxidative stress were apparently not involved in the pigment loss. Leaf chlorosis was attributable to a marked decrease in the chloroplast density caused by a reduction in the number of chloroplasts per cell and a change in cell size, suggesting that Cd interfered with chloroplast replication and cell division. Relatively little Cd was found in the chloroplasts and the properties of the photosynthetic apparatus (electron transport, protein composition, chlorophyll antenna size, chloroplast ultrastructure) were not affected appreciably in plants grown on Cd-polluted soil. Depth profiling of photosynthetic pigments by phase-resolved photoacoustic spectroscopy revealed that the Cd-induced decrease in pigment content was very pronounced at the leaf surface (stomatal guard cells) compared to the leaf interior (mesophyll). This observation was consistent with light transmission and fluorescence microscopy analyses, which revealed that stomata density in the epidermis was noticeably reduced in Cd-exposed leaves. Concomitantly, the stomatal conductance estimated from gas-exchange measurements was strongly reduced with Cd. When plants were grown in a high-CO2 atmosphere (4,000 microliters CO2 l-1), the inhibitory effect of Cd on growth was not cancelled, suggesting that the reduced availability of CO2 at the chloroplast level associated with the low stomatal conductance was not the main component of Cd toxicity in oilseed rape.

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Chlorophyll as an indicator of the upper critical tissue concentration of cadmium in plants

Cited by 31 publications

References 8 publications

Induction of cadmium tolerance by acclimation transferred between ramets of the clonal fern Salvinia minima Baker

Induction of cadmium tolerance by acclimation transferred between ramets of the clonal fern Salvinia minima Baker

Acclimation of Salix to metal stress

Leaf chlorosis in oilseed rape plants ( Brassica napus ) grown on cadmium-polluted soil: causes and consequences for photosynthesis and growth

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