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 CO2 assimilation during biogenesis of a C4 leaf. Changes in light‐induced O2 evolution and CO2 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 CO2 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 CO2 diffusion constitutes a major fraction of the total leaf resistance to CO2 assimilation implicating the stoma as the major limiting factor to photosynthetic CO2 assimilation.
|Original language||English (US)|
|Number of pages||12|
|State||Published - Oct 1981|
ASJC Scopus subject areas
- Plant Science