Seed provenance affects salt tolerance and germination response of the habitat-indifferent Salsola drummondii halophyte in the arid Arabian deserts

Abstract

Few species can survive well in both salty and non-salty soils (i.e., the habitat-indifferent halophytes). Little is known about the impact of soil salinity in different habitats on salt tolerance during seed germination. This study assesses effects of seed provenance of Salsola drummondii, a habitat-indifferent halophyte, on the individual effects and interactions between salt tolerance, photoperiod and thermoperiod on final germination, germination rate index (GRI) and recovery of germination from salt solutions. Seeds collected from plants grown in salty and non-salty soils were germinated in six salt solutions and incubated at three thermoperiod and two photoperiod regimes. Seeds were able to germinate and recover their germination in up to 1000 mM NaCl. Seeds from plants of non-salty soils germinated significantly better in up to 800 mM than those from salty soils, but the reverse was true at 1000 mM. The increase in salinity did not significantly affect GRI. Germination recovery was greater for seeds of plants from non-salty than for those from salty soils and for seeds germinated at lower than at higher thermoperiods. GRI of germination recovery increased with the increase in salinity level and was significantly higher for seeds of non-salty than of salty soils. Despite seeds of the two habitats are able to disperse to each other’s habitat, they differed in dormancy, GRI, and response to photoperiod and thermoperiod. Such difference could be considered the physiological basis for environmental cues that determine the proper space and time of germination that help in successful seedling establishment.