Alleviation of salinity and dark-enforced dormancy in Allenrolfea occidentalis seeds under various thermoperiods

Abstract

The effect of germination-regulating chemicals on the alleviation of salinity-enforced germination inhibition of Allenrolfea occidentalis (S.Wats.) Kuntze at various thermoperiods in complete darkness was investigated. There was poor germination at cool temperatures and germination-regulating chemicals were ineffective in alleviating this effect. Germination in the dark increased progressively with increase in temperature and maximum germination was obtained at 25–35˚C thermoperiod. Ethephon and fusicoccin (FC) substantially reverted dark-induced inhibition at moderate thermoperiods. All other germination-regulating chemicals were more effective at moderate temperature, while germination was not specifically different from control at higher temperature. Salinity-enforced germination inhibition was partially alleviated by all growth regulators at the higher temperature regime (25–35˚C). Best reversal was obtained with the application of ethephon and FC. Our results suggest that temperature is the most critical factor influencing the germination of Allenrolfea seeds. Allenrolfea occidentalis seeds germinated better at higher than at lower temperatures in the dark and all of the growth-promoting compounds showed their maximum reversal effect at higher temperatures.