Carbon dioxide assimilation and photosystem II deficiency in bundle sheath strands isolated from C4 plants

Usuda, H. and Kanai, R. and Miyachi, S. (1975) Carbon dioxide assimilation and photosystem II deficiency in bundle sheath strands isolated from C4 plants. Plant & Cell Physiology, 16. pp. 485-494.

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Abstract

The activities of Hill reaction and photosynthetic 14CO2 fixation in bundle sheath strands enzymatically isolated from millet (Panicum miliaceum) were 3–15 times as high as those observed in corn (Zea mays). In both preparations, 3-phosphoglycerate was the initial 14CO2 fixation product and the radioactivity was incorporated into sucrose and insoluble compounds (glucose-polymers) during the later period. After 20 sec of photosynthetic 14CO2 fixation, the percent of 14C incorporated into sugar phosphates in millet was about 3 times as high as that in corn, while in corn, the percent of 14C in 3-phosphoglycerate was higher than that observed in millet throughout the experimental period. When 14C-phosphoglycerate was added to the isolated bundle sheath strands, the rates of transfer of the radioactivity to dihydroxyacetone phosphate and sugar diphosphates in millet were significantly higher than those in corn. These results indicate that in the bundle sheath strands isolated from corn in which photosystem II activity is deficient, the reductive pentose cycle is impaired at the reduction step of 3-phosphoglycerate to glyceraldehyde phosphate due to the limited supply of NADPH through the photoelectron transport system. In contrast, the bundle sheath strands isolated from millet which have adequate photosystem II activity can carry out normal photosynthetic CO2 fixation.

Item Type: Article
Author Affiliation: Institute of Appled MIcrobiology, University of Tokyo, Bunkyo-ku, Tokyo
Subjects: Atmosperic Science > Climatology
Plant Protection
Divisions: General
Depositing User: Mr B Krishnamurthy
Date Deposited: 19 Mar 2012 11:10
Last Modified: 19 Mar 2012 11:10
Official URL: http://pcp.oxfordjournals.org/content/16/3/485.abs...
URI: http://eprints.icrisat.ac.in/id/eprint/3982

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