Abstract
Variation in seed weight is common within and among plant species, but few studies have attempted to document the pattern of seed weight and germination attributes for aquatic macrophytes at a large scale. This study examined within-species variation in seed weight and germination attributes and the effects of environmental factors on seed traits of the submerged plant Potamogeton pectinatus in the arid zone of northwest China. Our results showed that the average seed weight was 0.24 g per 100 seeds with a coefficient of variation (CV) of 28.4% among the eight P. pectinatus populations. The total germination fraction of seeds of P. pectinatus was relatively poor, less than 35% in seven P. pectinatus populations, and the lowest germination percentage found was only 2%. There were significant differences in seed weight, time to onset of germination, and total germination fraction among the eight different populations. Hierarchical partitioning analysis showed a strongly positive correlation between seed weight and water temperature and pH. Seed weight and the maternal environmental factors significantly affected both time to initiation of germination and total germination fraction. Our results suggest that (1) seed weight variation in P. pectinatus primarily is the result of temperature variation during fruit development; (2) relatively poor germination fraction suggests that seeds are relatively unimportant in the short-term survival of populations and that it may be another adaptive trait allowing plants to take place in the right place and at the right time, especially in harsh environment; and (3) variation in seed germination traits should be determined by local environmental and intrinsic factors that interact in a complex fashion.
Highlights
Seed traits, including seed weight and germination, are critical characters of the life histories of higher plants (Harper 1977; Ellison 2001), and their importance to plant fitness is widely appreciated (Baskin and Baskin 1998; Tremayne and Richards 2000)
There was great variation in mean seed weight per 100 seeds in the eight P. pectinatus populations sampled, ranging from 0.16 Æ 0.002 g to 0.35 Æ 0.001 g, and the heaviest seeds occurred in P1, and the lightest seed occurred in P5 (Table 1)
Comparative analyses of seed weight and seed germination traits have been especially useful in illustrating the broad range of seed traits that occur within taxa, and the environmental constraints that limit variability in characters (Ellison 2001)
Summary
Seed traits, including seed weight and germination, are critical characters of the life histories of higher plants (Harper 1977; Ellison 2001), and their importance to plant fitness is widely appreciated (Baskin and Baskin 1998; Tremayne and Richards 2000). Patterns of seed weight and germination and the respective controlling factors have been widely studied in the past few decades (Totland and Birks 1996; Tremayne and Richards 2000; Moles et al 2007; Linkies et al 2010). Comparisons of seed weight within species may show more subtle variation between populations, and research results will provide clues on how environmental factors influence seed characteristics that allow us to consider adaptation of seed traits for plants with wide distributions.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
