Abstract:

Germination tests of two water regimes were used to evaluate traits, mainly

community structure, of the soil seed bank of Honghu wetland withdrawn from

long-term rice culture.

One-way ANOVA was employed by means of diversity, richness and evenness

indices, and seed density. To evaluate the role of seed bank in restoration of wetland

communities, a soil core was sampled in June 2000, December 2000, March 2001 and

May 2001. Furthermore, the delamination of the seed bank was conducted by comparing

seed densities at different depths in the soil in the March 2001 sample. The results

showed that: 1) seed density in different seasons varied a lot, from 2.90×10 4

ind.·m-2 in June 2000 to 2.61×10 5 ind.·m-2 in December 2000. The size of the seed

bank in Honghu wetland is the largest among all the types of seed banks. The seed

bank belonged to the IV type of the Thompson and Grime model of soil seed banks of

different habitats. 2) For the community of the soil seed bank of Honghu wetland,

Simpson and Shannon-Wiener diversity indices, and Shannon evenness index were

maximal in June 2000, and minimal in December 2000. 3) The number of species had

no significant difference between soil depths of 0-5 cm and 5-10 cm. The seed density

in the upper layer accounted for 78% of the total seed number of the two layers,

which indicated that it was creditable to study only the upper level (0-5 cm) in

this kind of research. 4) Seed germination was affected by water depths in both number

of species and number of individuals of seedlings. 5) Degrees of similarity between

species composition of soil seed banks and that of the wetland vegetation during

December, March and May were 33.3%, 20.8% and 15.4%, respectively. They were

considerably high compared to those of some other types of habitats. 6) Seeds of

typical wetland species were scarce in all sampling periods, suggesting that in order

to restore the vegetation of the disturbed wetland more quickly, external seed banks

with abundant wetland species need to be introduced rather than only depending on

the original ones.