Germination of Dyckia encholirioides (Gaudichaud) Mez var. encholirioides under saline conditions

摘要

Dyckia encholirioides (Gaudichaud) Mez var. encholirioides is an endangered endemic bromeliad occurring in the Brazilian Atlantic Forest running along of the Atlantic Ocean. We investigated its seed germination at different salt levels (0, 100, 200, 300, 400 and 500 mmol L~(-1) NaCl) under different temperature regimes (10-20, 15-25, 20-30 and 25-35 deg C). The highest seed germination rate was obtained at 0, 100 and 200 mmol L~(-1) NaCl at 20-30°C and a further increase in salinity resulted in a gradual decrease in germination. Less than 5% of seeds germinated at 500 mmol L~(-1) NaCl. Few seeds germinated at concentrations higher than 200 mmol L~(-1) NaCl. Germination rate was fastest at 20-30 deg C and slowest at 10-20 deg C. Low seed germinationrate was obtained in the dark in comparison to seeds germinated in a 12 hours photoperiod under saline conditions. Recovery experiments showed that exposure of seeds to various salinity and temperature regimes had little effect on viability of seeds D.encholirioides.