首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Glycolate synthesis in a C3 C4 and intermediate photosynthetic plant type
Authors:Servaites  J C; Schrader  L E; Edwards  G E
Institution:1Department of Agronomy, University of Wisconsin Madison, Wisconsin 53706, U.S.A.
2Department of Horticulture, University of Wisconsin Madison, Wisconsin 53706, U.S.A.
Abstract:Excised leaves of a C3-photosynthetic type, Hordeum vulgare,a C4-type, Panicum miliaceum, and an intermediate-type, Panicummilioides, were allowed to take up through their cut ends a1 mM solution of butyl hydroxybutynoate (BHB), an irreversibleinactivator of glycolate oxidase. After 30 to 60 min in BHB,extractable glycolate oxidase activity could not be detectedin the distal quarter of the leaf blades. Following this pretreatment,recovery of 14C-glycolate from 14CO2 incorporated in a 10 minperiod was nearly maximal for each of the three plant types.Labeled glycolate was 51% of the total 14CO2 incorporated forthe C3-species, 36% for the intermediate-species, and 27% forthe C4-species Increased labeling of glycolate was compensatedfor primarily by decreased labeling of the neutral and basicfractions for the C3 and intermediate-type species. In the C4-type,label decreased primarily in the neutral and insoluble fractions,but increased in the basic fraction. A lower rate of glycolatesynthesis is indicative of a lower rate of photorespirationand consistent with a lower O2/CO2 ratio present in the bundle-sheathcells of C4-plants. We conclude that both decreased glycolatesynthesis and the refixation of photorespiratory-released CO2are important in maintaining a lower rate of photorespirationin C4-plants compared to C3 plants. Intermediate glycolate synthesisin Panicum milioldes is consistent with its intermediate levelof O2 inhibition of photosynthesis and intermediate rate ofphotorespiration. (Received May 6, 1978; )
Keywords:
本文献已被 Oxford 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号