Seed size and shade-tolerance: a comparative analysis of North American temperate trees

Abstract

Large seed size is a trait associated with plant species of mature, closed habitats, and is thought to supply an ample nutrient reserve necessary for seedling establishment. While this relationship has been shown for annuals and short-lived perennials, it is poorly documented for trees. A comparative method was used to determine whether North American temperate tree species which typically establish in shady conditions have larger seeds than those requiring more open conditions. Both angiosperms (hardwoods) and gymnosperms (conifers) were involved in the study. A significant relationship was found between large seed mass and shade-tolerance for angiosperms, but not for gymnosperms. These contrasting results seem to relate to unique evolutionary opportunities or constraints in different taxa. The absence of a relationship for gymnosperms is discussed in terms of character traits which might prevent seed size selection in response to shade. The finding for angiosperms underlines the importance of the regeneration niche in promoting coexistence among temperate hardwood species through seed size differentiation.

Adaptive Species Differentiation and Population Uniformity in Viola Species Sharing Similar Geographical Distribution but Differing Habitat Preferences

“…On the other hand, V. eizanensis, grows in closed and more stable woodland habitats and produces fewer CL seeds, which are potentially better able to survive in shaded environments with correspondingly fewer resources, and withstand unfavorable conditions for seed germination and seedling growth. Such association between light conditions and seed number/size has been observed in some plant species (Foster & Janson, 1985;Grubb & Metcalfe, 1996;Hewitt, 1998).…”

Morphological variation in fruits and seeds of Ceiba aesculifolia and its relationship with germination and seedlings biomass

“…In general, it is assumed that species with small seed produce more seedlings, but their establishment and survival success are lower, compared to those of species with larger seeds (Moles & Westoby 2006). These differences may be due to the amount of reserves stored by seed cotyledons, which are used for growth in early development stages (roots and photosynthetic tissue) (Hewitt 1998, Kitajima 2002, Soriano et al 2011. In the case of Ceiba aesculifolia, trees with larger seeds, which show the highest contents of lipids and water, produced seedlings with greater biomass, which could increase their establishment and survival probabilities.…”

Does Seed Size Affect Water Stress Tolerance in Quercus leucotrichophora A. Camus at Germination and Early Seedling Growth Stage?

“…This may enable early development of an enlarged resource gathering system (root or photosynthetic tissue) to produce a faster growing plant 45 and large seeds can withstand unfavorable environmental conditions over a long period of time, while smaller seeds under the same condition deplete their reserves in the process of respiration and physiological rearrangements.…”