A COMPARATIVE-STUDY OF THE SEED-GERMINATION BIOLOGY OF A NARROW ENDEMIC AND 2 GEOGRAPHICALLY-WIDESPREAD SPECIES OF SOLIDAGO (ASTERACEAE) - 6 - SEED BANK

Seeds of the geographically-widespread Solidago altissima and S. nemor alis and the narrow-endemic S. shortii were buried in pots of soil and placed in a glasshouse without temperature control. After 0.3-4.3 yea rs of burial, some seeds (21-60%) of all three species were viable and they germinated to 75-100% during 2 weeks of incubation in light at 3 0/15 degrees C. Soil samples collected from several population sites o f S. altissima, S. nemoralis and S. shortii were placed in the glassho use and monitored for seedling emergence. During the first, second, th ird, fourth, fifth and sixth springs, the number of S. altissima seedl ings m(-2) emerging was 108-1080, 8-494, 0-520, 0-69, 0-6 and 3, respe ctively, of S. nemoralis was 108-1122, 17-667, 0-42, 0-6, 0 and 0, res pectively, and of S. shortii was 61-1753, 0-25, 0-6, 0, 0 and 0, respe ctively. More seedlings emerged from disturbed than from non-disturbed soil, but the differences were not significant. Thus, although some s eeds of all three species buried in pots remained viable in soil throu ghout the 4.3-year burial period, longevity was greater and size of se ed bank larger in field-collected soil samples containing seeds of the geographically-widespread species than in those containing seeds of t he narrow endemic. Although 34 studies have reported seeds of 17 speci es of Solidago present in soil seed banks, the present study is the fi rst to show conclusively that Solidago can form a persistent seed bank .