Invited Review: Seed germination and salinity tolerance of habitat-indifferent halophytes as associated with geographical distribution

Germination response to environmental factors often depends on the seed source. Habitat-indifferent halophytes that can grow well under both saline (SH) and non-saline habitats (NSH) offer a good opportunity to understand salinity tolerance during the germination stage under varying environmental factors, such as temperature and light. This study compared seed germination responses among different populations of two common habitat-indifferent halophytes (Salsola drummondii and Suaeda vermiculata) from subtropical hyperarid deserts of the United Arab Emirates (UAE) and semiarid warm sub-tropical areas in Pakistan. This study highlights many similarities and differences in the seed germination and recovery responses of habitat-indifferent halophytes occurring in two contrasting climatic regions. The germination window of UAE seeds was wider, i.e., they germinated at higher rates under all temperatures in both light and darkness. This indicates that seeds of UAE populations can germinate at any time of the year, if conditions are optimal, and faciltate a faster seedling establishment under fluctuating harsh environmental conditions compared to populations from semiarid warm sub-tropical areas in Pakistan. The eco-physiological significance of the responses is also discussed.