Seed mass, dormancy and germinability variation among maternal plants of four Arabian halophytes

Abstract

Abstract Coastal desert vegetation of the Arabian Peninsula is almost entirely dominated by halophytes. Natural populations provide a genetic resource for ecological remediation and may also have direct economic value. High intrapopulation variation of seed traits is presumed to increase population persistence in the unpredictable climatic conditions of this hyper-arid desert. We investigated whether intrapopulation variation of seed mass, dormancy and germinability of four species was attributable to maternal individuals. Arthrocnemum macrostachyum, Halothamnus iraquensis, Haloxylon salicornicum and Seidlitzia rosmarinus are commonly distributed Arabian halophytes with differing seed weight variation. All species exhibited a higher germination when exposed daily to 12 h light, compared to seeds in darkness. A higher germination was correlated with a shorter germination time. For H. iraquensis and S. rosmarinus, a shorter germination time was negatively correlated with germination synchrony. H. salicornicum showed the highest intrapopulation variation of seed traits, followed by A. macrostachyum, S. rosmarinus and H. iraqensis. We found that individuals within populations of all the studied species showed variability in germination but the extent of variation was species-specific. The variation in seed mass and germination among the individuals of the studied species may facilitate a temporal distribution of germination, which may reduce the risk of seed bank exhaustion. The results of this study could assist conservation and management by improving the efficiency of seed collection from wild populations of these species.