A COMPARATIVE-STUDY OF THE SEED-GERMINATION BIOLOGY OF A NARROW ENDEMIC AND 2 GEOGRAPHICALLY-WIDESPREAD SPECIES OF SOLIDAGO (ASTERACEAE) .5. EFFECT OF DRY STORAGE ON AFTER-RIPENING AND SURVIVORSHIP

The effect of dry storage under ambient laboratory conditions on after -ripening and survivorship was tested on seeds of the geographically-w idespread Solidago altissima and S. nemoralis and the narrow-endemic S . shortii. Freshly-matured seeds of S. altissima collected in 1991 and in 1992 germinated to low or moderate percentages in light at 15/6, 2 0/10 and 25/15 degrees C and to high percentages at 30/15 and 35/20 de grees C, whereas those of S. nemoralis and S. shortii germinated to lo w percentages over the range of temperature regimes. After 0.8-1.8 yea rs of storage, 1991 seeds of S. altissima incubated in light germinate d to high percentages at 25/15, 30/15 and 35/20 degrees C, those of S. nemoralis did so at 30/15 and 35/20 degrees C and those of S. shortii at 20/10, 25/15, 30/15 and 35/20 degrees C; 1992 seeds of all three s pecies germinated to high percentages at 20/10, 25/15, 30/15 and 35/20 degrees C. Freshly-matured 1991 and 1992 seeds of the three species g erminated to low percentages in darkness over the range of temperature regimes, and only seeds of S. shortii germinated to high percentages after 0.8-1.8 years of storage. Compared with cold stratification, dry storage was only moderately effective in breaking dormancy in these t hree species. The primary difference in after-ripening of seeds of the three species was that seeds of the narrow endemic germinated to high er percentages in darkness than those of its two geographically-widesp read congeners. Survivorship curves for 1991 and 1992 seeds of S. alti ssima and S. nemoralis and for 1992 seeds of S. shortii were of Deevey Type I; the survivorship curve for 1991 seeds of S. shortii was close st to Type II. Longevity of 1991 seeds of S. altissima, 1992 seeds of S. nemoralis and 1991 and 1992 seeds of S. shortii was <4.0 years, whe reas that of 1991 seeds of S. nemoralis was <2.3 years; 5% of 1992 see ds of S. altissima were viable after 4.0 years.