Interveinal Distance for Carbohydrate Transport in Leaves of C3 and C4 Grasses
1974
Crookston, R Kent | Moss, Dale N.
Among common crop and range Gramineae, we found that species with the C₄ pathway for photosynthesis had fewer cells between leaf vascular bundles than did C₃ species. We extracted chlorophyll from leaf segments of 10 Ca and 10 C₄ species, cleared the segments in 10% aqueous NaOH, counted the number of mesophyll cells between vascular bundle sheaths, and measured the distance (center to center) between the vascular bundles. The C₃ species had 9 to 15 mesophyll cells between vascular bundle sheaths, while the C₄ species had only 2. The vascular bundles were 0.18 to 0.36 mm (average 0.27) apart in C₃ species, but only 0.08 to 0.15 mm (average 0.11) apart in C₃ species. The closeness of all leaf cells to vascular tissue in C₄ species suggests efficiency for transporting the products of photosynthesis and may be an important factor in their greater capacity to fix CO₂.
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