Germination characteristics of Zannichellia palustris from New South Wales, Australia

We describe the germination characteristics of a population of Zannichellia palustris from the Hunter region of New South Wales, Australia. Laboratory experiments indicate that germination of Z. palustris is affected by temperature, dormancy, stratification and salinity. Five trials, conducted at 30-day intervals, on stored seeds were undertaken. The pattern of germination differed between fresh seed and seed-bank seeds. Higher germination occured at 20 °C (18-67%) than 28 °C (7-60%) and seeds within the seed-bank outperformed fresh seeds (49 versus 36%), in terms of total percentage and rate of germination. Germination was lower in freshly collected seeds and increased after harvest, peaking in 1- and 2-month old seeds, before tapering off (40, 54, 58, 35, 22%, respectively). Stratification enabled a higher and more regularly paced germination to occur. However, no significant difference was discerned between seeds stratified at 5 °C for 30 days and non-stratified seeds. Although salinity did not appear to affect seed viability, concentrations of ≥6 ppt NaCl prevented germination. These germination patterns suggest that cool water, cold stratification and low salinity are optimal germination conditions.