EFFECT OF SALINITY, TEMPERATURE, AND GROWTH-REGULATORS ON THE GERMINATION AND EARLY SEEDLING GROWTH OF ATRIPLEX GRIFFITHII VAR STOCKSII

Seed germination and early seedling growth of Atriplex griffithii var. stocksii from seeds collected from a saline desert habitat in Karachi, Pakistan, were studied. The seeds of A. griffithii did not germinate under high salt stress (516 mM NaCl). Best germination percentages were obtained in distilled water. Seed germination was stimulated in light at cooler alternating temperature (25:10 degrees C) and inhibited at warmer temperature (30:15, 30:20, and 35:25 degrees C) regimes. Early seedling growth showed responses towards salinity and temperature that were similar to the germination responses. Both GA(3) and kinetin alleviated salinity-induced germination inhibition, and in most cases germination was stimulated by growth regulator treatments. A low concentration of kinetin (0.46 mu M) and a high concentration of GA(3) (28.9 mu M) significantly promoted early seedling growth at all salinity treatments.