The effect of some hormones and nitrogenous compounds on capacity, velocity and synchrony of germination of Zygophyllum atriplicoides seeds under salinity stress

Zygophyllum atriplicoides، a perennial shrub in the family Zygophylaceae، is one of the important halophytes in Iran. In this research، seeds of this species were collected from the salt zones near Isfahan City. Experiment was carried out in order to determine the salinity-alleviating effect of germination promoting compounds (GPCs) on its seed germination as factorial with completely randomized design with 4 replications. GPCs were including: nitrate (20 mM)، Thiourea (10 mM)، Ethephon (10 mM)، GA3 (3 mM) and water as control and salinity concentrations were 0، 40، 80 and 120 mM NaCl. In water treatment (0 mM NaCl) only 50% of seeds germinated and germination decreased with an increase in salinity to 40، 80 mM، and at 120 mM NaCl، seed germinated was less than 3%. Also salinity decreased capacity، velocity and synchronization index of germination. All GPCs significantly enhanced germination in control treatment (0 mM NaCl). Nitrate and thiourea increased 30-40 % seed germination than water treatment، but in 80، 120 mM did not have significant promotive effect on germination than water treatment. At 40 mM NaCl، Ethephon and GA3 application significantly promoted germination at all salinity levels. In 0، 40، 80 and 120 mM NaCl، Ethephon and GA3 promoted germination 92، 68، 51، 25 % and 100، 97، 86، 75 % respectively. Therefore، GA3 better than other chemicals، alleviated the inhibitory effects of all salinity levels on the germination of Z. atriplicoides and increased capacity، velocity and synchronization index of germination. In sum، our data suggests that innate dormancy of Zygophyllum atriplicoides seeds is non-deep physiologic type and salt-induced dormancy، is caused probably because of distortion of seed hormonal balance and exogenous GA3 application compensated this hormonal un-balance and led to dormancy breaking and germination of Zygophyllum atriplicoid seeds.