Assimilation of 14CO2 by the Inflorescence of Poa annua L. and Lolium perenne L.

The relative assimilatory activity of the inflorescence, itsindividual components, and the leaves of flowering tillers ofPoa annua L. and Lolium perenneL. was determined over the periodfrom inflorescence emergence to seed shedding. The pattern of¹⁴CO₂ fixation was similar for both species and the inflorescencewas by far the most important assimilatory organ of the reproductivetiller, particularly over the latter period of seed developmentas leaf senescence progressed. With the exception of the seedsall parts of the inflorescence showed significant assimilatoryactivity and the lemmas and paleas accounted for 40–50per cent of the total ¹⁴C fixed by the inflorescence in bothspecies. The importance of the grass inflorescence as a photosyntheticstructure is discussed in relation to similar studies on cereals. Poa annua, Lolium perenne, carbon dioxide assimilation, inflorescence