Premium
LIMITATIONS OF PHOTOSYNTHESIS IN DIFFERENT REGIONS OF THE ZEA MAYS LEAF
Author(s) -
MIRANDA VALENTINE,
BAKER NEIL R.,
LONG STEPHEN P.
Publication year - 1981
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1981.tb07481.x
Subject(s) - photosynthesis , c4 photosynthesis , rubisco , biology , botany , phosphoenolpyruvate carboxylase , pyruvate carboxylase , ribulose , chlorophyll , carboxylation , chlorophyll fluorescence , assimilation (phonology) , biochemistry , enzyme , linguistics , philosophy , catalysis
S ummary The progressive development of the photosynthetic apparatus occurring along the length of the Zea mays leaf offers a convenient system with which to examine the limitations to photosynthetic CO 2 assimilation during biogenesis of a C 4 leaf. Changes in light‐induced O 2 evolution and CO 2 assimilation, chlorophyll content, activity of PEP‐carboxylase, NADP‐malic enzyme and the ‘R5P system’ (consisting of d ‐ribose‐5‐phosphate‐keto isomerase, ATP‐ d ‐ribulose‐5 phosphate 1‐phosphotransferase and d ‐ribulose‐1,5‐bisphosphate carboxylase) and fluorescence emission characteristics were examined along the length of the second leaf of 7‐day‐old plants grown under a diurnal light regime. The results suggest that the major limitation to CO 2 assimilation in the leaf sheath lies within the chlorenchyma and is either energy supply for carboxylation or the capacity of key photosynthetic enzymes. In the leaf blade stomatal resistance to CO 2 diffusion constitutes a major fraction of the total leaf resistance to CO 2 assimilation implicating the stoma as the major limiting factor to photosynthetic CO 2 assimilation.