Germination, storage and viability testing of seeds of Zostera capricorni Aschers. from a tropical bay in Australia

Abstract

The effects on the germination of Zostera capricorni Aschers. of several factors, including salinity, temperature and incising the seed coat were investigated and analysed using analysis of variance. We also investigated methods for estimating the viability of Z. capricorni seeds, and their storage life. Soaking the seeds in 0.5% tetrazolium at 25°C for 18–24 h gave the most consistent staining pattern for testing the viability of Z. capricorni seeds. This method can now be used to ensure that seeds are viable before they are used in further studies of the germination and growth of seedlings or in rehabilitation projects. Low salinities (1–10‰) and incising the seed coat promoted rapid and almost complete germination of Z. capricorni, indicating the seeds do not have a primary dormancy. Temperature did not affect seeds in the lower salinities (1, 5 and 10‰). However, at higher salinities (20, 30 and 40‰) seeds only germinated at low temperatures (15°C). In Moreton Bay, salinities are rarely as low as 1–10‰; consequently Z. capricorni is most likely to germinate in winter, when temperature decreases. Paradoxically most Z. capricorni seeds are found in spring and summer, with very few present in winter. The most successful storage of Z. capricorni seeds was at 5–10°C in aerated water. Under these conditions 58 ± 10% (SE) of these seeds were still viable after 50 days.