Alleviation of seed dormancy in the desert forb Zygophyllum simplex L. from Pakistan

Zygophyllum simplex L. is a succulent annual that grows on the coastal and inland saline flats around Karachi, Pakistan. The seeds are moderately salt tolerant during germination. Germination of Zygophyllum simplex seeds under various salinity, proline, betaine, GA and kinetin treatments was determined. Proline (0.1 and 1 mM) and betaine (0.1 and 1 mM) alleviated the innate dormancy of seeds, and germination reached 60-70 % compared to 12% in the control set. Al low salinity compatible osmotica alleviated some effects of salinity, but at higher NaCl concentrations both proline and betaine were ineffective. Gibberellic acid (0.3 and 3 mM) and kinetin (0.05 and 0.5 mM) substantially alleviated both innate as well as salinity-induced seed dormancy. At higher salinity (125 mM), low concentrations of kinetin (0.05 mM) and high concentrations of GA (3 mM) were more effective. GA completely alleviated the effect of salinity at all concentrations used. (C) 1997 Annals of Botany Company.