Seed germination of a halophytic grass Aeluropus lagopoides

Aeluropus lagopoides (Linn.) Trin. Ex Thw. (Poaceae) is a perennial grass distributed from coastal Sindh and Balochistan to saline flats of Punjab. Pakistan. Seeds collected from an inland population of A. lagopoides located on the University of Karachi campus were germinated under various levels of salinity (0, 100, 200, 300, 400 and 500 mM NaCl) and temperature regimes (10/20, 15/25, 20/30 and 25/35 degreesC) in a 12 h dark/12 h light photoperiod. Highest germination was obtained under non-saline conditions, and an increase in NaCl concentration progressively inhibited germination. Inhibition of germination was greater at cooler temperatures (10/20 degreesC) when no seed germinated above a concentration of 300 mM NaCl. The germination response at moderate temperatures (20/30 degreesC) was optimal, with 30 % of seeds germinating in 500 mM NaCl. The rate of germination decreased as salinity increased. Germination rate was highest at 20/30 degreesC and lowest at 10/20 degreesC. Seeds were transferred from salt solutions to distilled water after 20 d and those from high salinities recovered quickly at warmer temperatures with an optimal response at 20/30 degreesC. (C) 2001 Annals of Botany Company.