Seed biology of the invasive species buffalobur (Solanum rostratum) in Northwest China

Buffalobur is an invasive summer annual species in Xinjiang Province, China. Our purpose was to investigate certain aspects of the seed biology of this weedy species that might be useful in controlling it. In contrast to a previous report that fresh seeds have physical (water-impermeable seed coat) plus physiological (low growth potential of embryo) dormancy, our results, along with those of others, verify that the seeds have only physiological dormancy. The seed's coat is water-permeable, the embryo is fully developed at seed maturity, and dormancy can be broken by cold stratification in the field during winter and early spring. Fifty-five percent of seeds buried in the soil in autumn germinated in the soil the following May, and 53% of the remaining nongerminated seeds germinated when tested in light in the laboratory. Thus, about 20% of the seeds did not germinate but were viable, demonstrating that the species forms at least a short-lived persistent seed bank. This information will be useful in planning a management strategy for this highly invasive species in northwest China.