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

The effect of germination-regulating chemicals on the alleviation of salini ty-enforced germination inhibition of Allenrolfea occidentalis (S.Wats.) Ku ntze at various thermoperiods in complete darkness was investigated. There was poor germination at cool temperatures and germination-regulating chemic als were ineffective in alleviating this effect. Germination in the dark in creased progressively with increase in temperature and maximum germination was obtained at 25 35 degreesC thermoperiod. Ethephon and fusicoccin (FC) s ubstantially reverted dark-induced inhibition at moderate thermoperiods. Al l other germination-regulating chemicals were more effective at moderate te mperature, 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 3 5 degreesC). Best reversal was obtained with the application of ethephon an d FC. Our results suggest that temperature is the most critical factor infl uencing the germination of Allenrolfea seeds. Allenrolfea occidentalis seed s germinated better at higher than at lower temperatures in the dark and al l of the growth-promoting compounds showed their maximum reversal effect at higher temperatures.