
TY  - JOUR
A1  - Hattersley, PW 
T1  - &#948;<sup>13</sup> Values of C<sub>4</sub> Types in Grasses
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1982
VL  - 9
IS  - 2
SP  - 139
EP  - 154
KW  - 
UR  - https://doi.org/10.1071/PP9820139 
N2  - &#948;13 values were determined for leaves of C4 grasses (Poaceae) of different photosynthetic types. For plants grown in the same environment at the same time, mean &#948;13 values for the three C4 types were: NADP-ME-type, - 11.350 ± 0.13 s.e. (11 spp.); PCK-type, - 11.950 ± 0.19 s.e. (11 spp.); and NAD-ME-type, -12.70 ± 0.21 s.e. (9 spp.). Although there is some overlap between the values for individual species of the three groups, the difference between any two means is highly significant [P(t) < 0.01] and is not due to taxonomic sampling bias at the subfamily level. The differences in means may suggest that C4 types differ in rates of leakage of CO2 and HCO3- from PCR tissue ('photosynthetic carbon reduction' tissue: equivalent to 'Kranz' tissue), and/or, using Farquhar's (Appendix) expression for plant &#948; values, that C4 types differ in their average intercellular CO2 concentrations (c1). It is also possible that differences between C4 types exist in some other, unknown, leaf fractionation process. Apoplastic CO2 leakage from PCR tissue in NAD-ME-type C4 grasses, which do not possess a PCR 'suberized lamella' as found in NADP-ME- type and PCK-type C4 grasses, may give these species the most negative &#948;13 values. Expressions for C4 plant &#948;13 values, and a model for the &#948;13 values of CO2 and HCO3- in various pools and fluxes in C4 plant leaves, are given. 
ER  -

