A preliminary study on seed germination of dominant plants from a karst landscape in Bijie, Guizhou.

This study compared the germination characteristics of 11 woody species from a Karst landscape in Bijie,Guizhou Province. The results showed that:seeds of Rhus chinensis、Quercus fabri、Hypericum kouytcheouense、Platycarya strobilacea、Pyracantha fortuneana germinated within 4 weeks and the seeds of other species showed different degrees of dormancy,while seeds of Carpinus pubescens had dead embryos. Germination rate of Rhus chinensis、Hypericum kouytcheouense、Platycarya strobilacea was significantly higher in light than in dark which indicated a light demanding for germination of those species. Seeds of Quercus fabric and Pyracantha fortuneana germinated in both light and dark environment and the germination rates showed no significant difference in two treatment which indicated a non-photoblastic germination. Germination rate of Rhus chinensis、Hypericum kouytcheouense achieved the highest level at 30℃. The optimal germination temperature for Quercus fabri and Pyracantha fortuneana were 15℃ and 20℃,respectively. The seeds cannot tolerate high temperature. The optimal germination temperature for Platycarya strobilacea was 20℃ and seeds could not tolerate both lower and higher temperature. Although the water permeability of seeds of Zanthoxylum dimorphophyllum reached up to 85%,the embryo embedded in the endosperm was very small and undeveloped. The seeds might experience morphological or morphphysiological dormancy. The water permeability of seeds of Cotoneaster horizontalis,Stachyurus himalaicus,Stachyurus yunnanensis all exceeded 20% and the ratio of embryo length and seed length reached up to 1/2 of fully developed embryos. Seeds described above might have physiological dormancy. The water permeability of seeds of Rosa cymosa was about 27% and the ratio between embryo length and seed length reached up to 2/3 and the embryo was undeveloped which indicated that the seeds might have morphophysiological dormancy.