Effect of seed size on germination in three species from arid Arabian deserts

Abstract

In many species, seeds with different sizes show diverse responses in their requirements for temperature and light for optimal germination. In this study, the effect of seed size (i.e., small and large) on germination was tested in seeds of Brassica tournefortii Gouan, Lotus garcinii DC., and Salvadora persica L. from arid Arabian Desert habitats. The mean seed size of all three study species differs significantly between small and large-sized seeds. Differences were observed in seed germination between large and small seeds of B. tournefortii and L. garcinii. We found that the large seeds of B. tournefortii and L. garcinii showed a higher germination percentage at all tested temperatures than that displayed by the small seeds. However, both small and large seeds of S. persica germinated equally (100%) well under all tested incubation conditions. Our results show significant differences in germination percentage between the small and large seeds of B. tournefortii at 25/35 °C under a 12 h light regime. However, seeds of L. garcinii showed a significant difference in germination percentage at low temperatures (15/25 °C) under a 12 h light regime.