Degree of C4 Photosynthesis in C4 and C3-C4Flaveria Species and Their Hybrids
| Autor: | R. Harold Brown, Clanton C. Black, George T. Byrd |
|---|---|
| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Plant Physiology. 100:947-950 |
| ISSN: | 1532-2548 0032-0889 |
| DOI: | 10.1104/pp.100.2.947 |
| Popis: | Hybrids have been made between species of Flaveria exhibiting varying levels of C4 photosynthesis. The degree of C4 photosynthesis expressed in four interspecific hybrids (Flaveria trinervia [C4] × F. linearis [C3-C4], F. brownii [C4-like] × F. linearis, and two three-species hybrids from F. trinervia × [F. brownii × F. linearis]) was estimated by inhibiting phosphoenolpyruvate carboxylase in vivo with 3,3-dichloro-2-dihydroxyphosphinoylmethyl-2-propenoate (DCDP). The inhibitor was fed to detached leaves at a concentration of 4 mm, and apparent photosynthesis was measured at atmospheric levels of CO2 and at 20 and 210 mL L−1 of O2. Photosynthesis at 210 mL L−1 of O2 was inhibited 32% by DCDP in F. linearis, by 60% in F. brownii, and by 87% in F. trinervia. Inhibition in the hybrids ranged from 38 to 52%. The inhibition of photosynthesis by 210 mL L−1 of O2 was increased when DCDP was used, except in the C4 species, F. trinervia, in which photosynthesis was insensitive to O2. Except for F. trinervia, control plants with less O2 sensitivity (more C4-like) exhibited a progressively greater change in O2 inhibition of photosynthesis when treated with DCDP. This increased O2 inhibition probably resulted from decreased CO2 concentrations in bundle sheath cells due to inhibition of phosphoenolpyruvate carboxylase. The inhibition of photosynthesis by DCDP is concluded to underestimate the degree of C4 photosynthesis in the interspecific hybrids because increased direct assimilation of atmospheric CO2 by ribulose bisphosphate carboxylase may compensate for inhibition of phosphoenolpyruvate carboxylase. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|