Rosa soulieana seed dormancy and germination

This is from an article in the September 2008 issue of the Belgian Journal of Botany.


Successful restoration of vegetation in dry valleys under strong anthropogenic disturbance in southwestern China is limited by lack of information on the germination requirements of many native plants, including some rose species. Effects of post-dispersal factors (temperature, moisture and light) on Rosa soulieana seed dormancy and germination were examined in order to predict the rate and timing of germination in the field. Dry storage, cold stratification, and warm plus cold stratification increased both germination percentages and germination rates. Warm plus cold stratification was most effective in breaking achene dormancy, followed by cold stratification and dry storage. Light during cold stratification had no effect on dormancy break. Germination occurred from 5°C to 30°C. At low temperature, diurnal alternating temperature (5/15°C) was more effective than constant temperature (5°C) in stimulating germination. Water stress significantly led to a decrease in germination percentage and rate. Significant differences under various photon irradiances were observed neither in germination percentages nor in germination rates. Temperature and moisture, but not light, appeared to play important roles in regulating dormancy and germination. Our results suggest that R. soulieana seeds may germinate sporadically from early spring to summer when soil moisture is sufficient for them to initiate this process. However, most achenes should normally germinate in the spring, which is a general phenomenon in plants. For effective restoration of degraded vegetation in dry valleys, it would be recommended to sow fresh achenes in autumn or achenes with dormancy broken in laboratory in early spring and relatively deep in the soil.