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COMPARATIVE  EFFECT  OF  NACL  AND  SEA SALT ON GERMINATION OF HALOPHYTIC GRASS PHRAGMITES KARKA AT DIFFERENT TEMPERATURE REGIMES

AFSHEEN ZEHRA AND M. AJMAL KHAN

Abstract: Seed germination of salt tolerant grasses, which could serve as non-conventional fodder/forage crop for saline land is more sensitive to salinity than dicotyledonous halophytes. Phragmites karka (Retz.). Steud., is a perennial halophytic grass, distributed in marshy places around Karachi. To determine tolerance limits of germination, we conducted germination experiments in NaCl and sea salt (0, 10, 20, 30, 40 & 50 dS m^-1) at alternating temperature regimes (10:20, 15:25, 20:30 and 25:35^oC) for 12h: 12h light: dark period & 24- h dark photoperiod. Increase in salinity substantially inhibited seed germination both in NaCl and sea salt. Germination in light was higher in comparison to dark. Effect of NaCl in general was not significantly different from sea salt and optimal germination percentages were obtained at 20:30^oC. However, NaCl prevented more seeds from germination at 25:35^oC in comparison to sea salt. Ungerminated seeds were transferred from salinity to distilled water after 20 days and the highest percentage of recovery was at 50 dS m^-1 both in NaCl (20:30^oC) and sea salt (10:20^oC & 20:30^oC). Increase in salinity significantly inhibited seed viability and lowest viable seeds were obtained at highest salinity.

Institute of Sustainable Halophyte Utilization, University of Karachi, Karachi-75270, Pakistan