Photosynthetic oxygen exchange in C4 grasses: the role of oxygen as electron acceptor

摘要: C 4 grasses of the NAD-ME type ( Astrebla lappacea , Eleusine coracana Eragrostis superba Leptochloa dubia Panicum coloratum decompositum ) and NADP-ME Bothriochloa bladhii, Cenchrus ciliaris, Dichanthium sericeum antidotale Paspalum notatum Pennisetum alopecuroides Sorghum bicolor were used to investigate role O 2 as an electron acceptor during photosynthesis. Mass spectrometric measurements gross evolution uptake made concurrently with net CO chlorophyll fluorescence at different irradiances leaf temperatures 30 40 ∞ C. In all increased increasing irradiance very high partial pressures p was on average 18% evolution. Gross 3.8 times greater than in dark. Furthermore, light concentration both compensation point, whereas dark insensitive concentration. This suggests that a significant amount may be associated Mehler reaction, reaction varies exchange characteristics similar for species. species had significantly point particularly low compared species, which could related rates photorespiratory uptake. There good correlation between transport estimated from .