Variations in seed size and seed mass related to tree growth over 5 years for 23 provenances of Quercus acutissima from across China

摘要

The origin of a seed strongly impacts its traits,and both origin and seed traits influence seed germination and seedling development.However,in many instances,this effect on the seedling does not persist into adulthood,and little is known about how seed traits and original environment affect seedling/tree growth over time.In this study,seed size,seed mass,seedling/tree growth and origins were collected and determined for 23 provenances of Quercus acutissima from across China.Origin variables correlated well with seed size and seed mass.In stepwise multiple regressions,a longitudinal aridity index explained 49.2–68.7% of the total variation in seed size and mass,while only seed width was correlated with seedling/tree height(H) and diameter at the ground(D) from seed traits and origins.The total variance in H and D explained by the models decreased over time,for example,the R^2 value of the models for H declined from 0.477 in the first year to 0.224 in the fourth year;no models was significant in the fifth year.These results indicate that seed size,regulated by the longitudinal aridity index strongly impacted seedling and tree growth,but the strength of the influence decreased over time,and disappeared after 4 years.