GERMINATION REQUIREMENTS IN A POPULATION OF TYPHA-LATIFOLIA

The physio-ecological requirements of germination and early achene gro wth of a population of Typha latifolia L. were studied. The effects of constant (10, 20 and 30 degrees C) or alternating (10/20 degrees, 20/ 30 degrees and 10/30 degrees C) temperatures, photoperiod (12/12, 8/16 , 6/18, 4/20, 2/22 and 0/24 h day/night), after-ripening time and cult ure medium salinity (NaCl) on germination were assessed, Results showe d that germination required light and alternating temperatures (optima l results at 20/30 degrees C with 12/12 h photo-thermoperiod). In thes e conditions the germination trend showed no appreciable variation dur ing the first year of achene after-ripening. The presence of more than 0.1 M NaCl in the culture medium caused a significant reduction in th e percentage of seeds germinating, and inhibited further seedling grow th. Typha latifolia can, therefore, be considered a helio-thermophilic and glycophilic species, at least during early growth stages. (C) 199 7 Elsevier Science B.V.