Glycolate synthesis in a C_3, C_4 and intermediate photosynthetic plant type

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概要

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• Excised leaves of a C_3-photosynthetic type, Hordeum vulgare, a C_4-type, Panicum miliaceum, and an intermediate-type, Panicum milioides, were allowed to take up through their cut ends a 1 mM solution of butyl hydroxybutynoate (BHB), an irreversible in-activator of glycolate oxidase. After 30 to 60 min in BHB, extractable glyc,olate oxidase activity could not be detected in the distal quarter of the leaf blades. Following this pretreatment, recovery of ^<14>C-glycolate from ^<14>CO_2 incorporated in a 10 min period was nearly maximal for each of the three plant types. Labeled glycolate was 51% of the total ^<14>CO_2 incorporated for the C_3-species, 36% for the intermediate-species, and 27% for the C_4-species. Increased labeling of glycolate was compensated for primarily by de-creased labeling of the neutral and basic fractions for the C_3 and intermediate-type species. In the C_4-type, label decreased primarily in the neutral and insoluble fractions, but increased in the basic fraction. A lower rate of glycolate synthesis is indicative of a lower rate of photorespiration and consistent with a lower O_2/CO_2 ratio present in the bundle-sheath cells of C_4-plants. We conclude that both decreased glycolate synthesis and the refixation of photorespiratory-released CO_2 are important in maintaining a lower rate of photorespiration in C_4-plants compared to C_3 plants. Intermediate glycolate synthesis in Panicum milioides is consistent with its intermediate level of O_2 inhibition of photosynthesis and intermediate rate of photorespiration.

• 日本植物生理学会の論文

著者

• Edwards G.e.

  Department Of Botany Washington State University:institute Of Biological Chemistry Washington State

• Schrader L.e.

  Department Of Agronomy University Of Wisconsin

• Servaites J.C.

  Department of Agronomy, University of Wisconsin

• Servaites J.c.

  Department Of Agronomy University Of Wisconsin

関連論文

• Distribution of enzymes related to C_3 and C_4 pathway of photosynthesis between mesophyll and bundle sheath cells of Panicum hians and Panicum milioides
• Photosynthetic Characteristics of C_3-C_4 Intermediate Flaveria Species II. : Kinetic Properties of Phosphoenolpyruvate Carboxylase from C_3-C_4 and C_3-C_4 Intermediate Species
• Differences in cold lability of pyruvate,Pi dikinase among C_4 species
• Photosynthetic efficiency of Panicum hians and Panicum milioides in relation to C_3 and C_4 plants
• Glycolate synthesis in a C_3, C_4 and intermediate photosynthetic plant type
• Use of inhibitors to distinguish between C_4 acid decarboxylation mechanisms in bundle sheath cells of C_4 plants

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