Mesophyll conductance ( To address this knowledge gap, we used online oxygen isotope discrimination measurements to estimate In this study, Our study suggests that greater
Mesophyll CO2conductance ( Using 16 C4grasses we investigated the response of In general, Our study advances understanding of CO2response of
- NSF-PAR ID:
- 10370309
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 236
- Issue:
- 4
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 1281-1295
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary g m) is the diffusion ofCO 2from intercellular air spaces (IAS ) to the first site of carboxylation in the mesophyll cells. In C3species,g mis influenced by diverse leaf structural and anatomical traits; however, little is known about traits affectingg min C4species.g mand microscopy techniques to measure leaf structural and anatomical traits potentially related tog min 18 C4grasses.g mscaled positively with photosynthesis and intrinsic water‐use efficiency (TE i), but not with stomatal conductance. Also,g mwas not determined by a single trait but was positively correlated with adaxial stomatal densities (SD ada), stomatal ratio (SR ), mesophyll surface area exposed toIAS (S mes) and leaf thickness. However,g mwas not related to abaxial stomatal densities (SD aba) and mesophyll cell wall thickness ( ).T CWSD adaandSR increasedg mby increasingS mesand creating additional parallel pathways forCO 2diffusion inside mesophyll cells. Thus,SD ada,SR andS mesare important determinants of C4‐g mand could be the target traits selected or modified for achieving greaterg mandTE iin C4species. -
Abstract In habitats with low water availability, a fundamental challenge for plants will be to maximize photosynthetic C‐gain while minimizing transpirational water‐loss. This trade‐off between C‐gain and water‐loss can in part be achieved through the coordination of leaf‐level photosynthetic and hydraulic traits. To test the relationship of photosynthetic C‐gain and transpirational water‐loss, we grew, under common growth conditions, 18 C4grasses adapted to habitats with different mean annual precipitation (MAP) and measured leaf‐level structural and anatomical traits associated with mesophyll conductance (gm) and leaf hydraulic conductance (Kleaf). The C4grasses adapted to lower MAP showed greater mesophyll surface area exposed to intercellular air spaces (Smes) and adaxial stomatal density (SDada) which supported greater gm. These grasses also showed greater leaf thickness and vein‐to‐epidermis distance, which may lead to lower Kleaf. Additionally, grasses with greater gmand lower Kleafalso showed greater photosynthetic rates (Anet) and leaf‐level water‐use efficiency (WUE). In summary, we identify a suite of leaf‐level traits that appear important for adaptation of C4grasses to habitats with low MAP and may be useful to identify C4species showing greater Anetand WUE in drier conditions.
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