Formation of photorespiratory glycollate and glyoxylate ín leaf discs of C3-C4 intermediates: reduced sensitivity to external bicarbonate

Title:

Formation of photorespiratory glycollate and glyoxylate ín leaf discs of C3-C4 intermediates: reduced sensitivity to external bicarbonate

Creator:

Tirumala Devi, M. and Raghavendra, A.S.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:81f43bac-4f1b-41f2-bf57-a3aeaab9cd0a
uuid:81f43bac-4f1b-41f2-bf57-a3aeaab9cd0a
urnnbn:urn:nbn:cz:aba007-000flm

Type:

model:internalpart and TEXT

Format:

print

Description:

Accumulation of glycollate or glyoxylate on irradiation of leaf discs in the presence of a-hydroxypyridinemethane sulfonate (a-HPMS) oř glycidate, respectively, was studied in C3-C4 intermediates of Altemanthera species (A. ficoides, A. tenellá) and Paríhenium hysíerophorus in comparison with the partem in C3 or C4 species. The levels of these two photorespiratory metabolites were reduced in the intermediates (< 75 % of that in C3) while being very low in the C4 species (about 10 % of that in C3). The inhibitory effect of bicarbonate on the glycollate or glyoxylate accumulation was pronounced in the C3 species (60 % inhibition), moderate in the intermediates (about 45 %), and very low (< 2 %) in the C4 plants. The negligible effect of bicarbonate on these photorespiratory metabolites in the C4 species is expected to be due to their C4 acid-based C02-concentrating mechanism. In the presence of 5 mM bicarbonate, the levels of glycollate and glyoxylate in the C3 species were similar to those in the C3-C4 intermediates. We speculate that a high intemal CO2 pool, possibly due to an efficient CO2 recycling/refixation mechanism, may be an additional reason besides the partial reduction in photorespiratory enžymic capacity for reduced levels of photorespiratory glycollate/glyoxylate in C3-C4 intermediates.Accumulation of glycollate or glyoxylate on irradiation of leaf discs in the presence of a-hydroxypyridinemethane sulfonate (a-HPMS) oř glycidate, respectively, was studied in C3-C4 intermediates of Altemanthera species (A. ficoides, A. tenellá) and Paríhenium hysíerophorus in comparison with the partem in C3 or C4 species. The levels of these two photorespiratory metabolites were reduced in the intermediates (< 75 % of that in C3) while being very low in the C4 species (about 10 % of that in C3). The inhibitory effect of bicarbonate on the glycollate or glyoxylate accumulation was pronounced in the C3 species (60 % inhibition), moderate in the intermediates (about 45 %), and very low (< 2 %) in the C4 plants. The negligible effect of bicarbonate on these photorespiratory metabolites in the C4 species is expected to be due to their C4 acid-based C02-concentrating mechanism. In the presence of 5 mM bicarbonate, the levels of glycollate and glyoxylate in the C3 species were similar to those in the C3-C4 intermediates. We speculate that a high intemal CO2 pool, possibly due to an efficient CO2 recycling/refixation mechanism, may be an additional reason besides the partial reduction in photorespiratory enžymic capacity for reduced levels of photorespiratory glycollate/glyoxylate in C3-C4 intermediates.

Language:

Multiple languages

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

455-463 and 137-145

Source:

Photosynthetica | 1994 Volume:30 | Number:3

Harvested from:

CDK

Metadata only:

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