Comparative evolutionary ecology of seed size

Westoby, Mark; Jurado, Enrique; Leishman, Michelle R.

doi:10.1016/0169-5347(92)90006-w

Cited by 535 publications

(453 citation statements)

References 34 publications

Supporting

Mentioning

413

Contrasting

Unclassified

Order By: Relevance

“…The large number of ovules per fruit in E. fleischeri and E. colchicum suggests a strong selection for a high seed set. Since resources for producing seeds are limited, a tendency towards smaller seeds would be expected unless selection for larger seeds is strong (WESTOBY et al 1992). Seed mass is commonly correlated with seedling success, but in stressful alpine habitats the success of a plant may depend to a large extend on its capacity for clonal growth.…”

Section: Trade-off Between Seed Mass and Numbermentioning

confidence: 99%

Differences in life history traits of relatedEpilobium species: Clonality, seed size and seed number

Stöcklin

1999

Folia Geobot

View full text Add to dashboard Cite

Small changes in morphology can affect the performance and functions of organisms and hence their ecological success. In modular constructed plants, contrasting growth strategies may be realized by differences in the spatial arrangement and size of shoots. Such differences change the way in which meristems and resources are assigned to various functions during the lifespan of a plant. If such changes include the capacity to spread clonally, sexual reproduction may also be affected. I compare patterns in vegetative growth and sexual reproductive traits in four allopatric species of Epilobium which are sometimes considered as subspecies of a single polymorphic taxon. The four species differ in the location of the buds which annually renew the aerial shoot system. E. dodonaei and E. steveni do not spread clonally and are characterized by a shrub-like habit. E. fleischeri, a species occurring only in the Alps, and E. colchicum, which occurs in the upper region of the Caucasus mountains, both produce buds on horizontal roots or plagiotropic shoots. Both alpine species exhibiting clonal growth have smaller shoots, fewer fruits and smaller seeds than the lowland species. An intraspecific trade-off between seed number per fruit and seed mass is realized. Both alpine species produce more seeds per fruit at the expense of seed mass. The morphological relationship between the four species and their geographical distribution suggest that clonal growth in E. fleischeri (restricted to the Alps) and E. colchicum (restricted to the Caucasus) is adaptively associated with the stressful conditions of alpine habitats. Our results suggest that clonal growth is not necessarily correlated with reduced reproduction by seeds. The success of plants which are already established may largely depend on clonal spread, but the colonization of new habitats depends on the production of a large number of small seeds with high dispersability.

show abstract

Section: Trade-off Between Seed Mass and Numbermentioning

confidence: 99%

Differences in life history traits of relatedEpilobium species: Clonality, seed size and seed number

Stöcklin

1999

Folia Geobot

View full text Add to dashboard Cite

show abstract

“…As seed number is related directly to fitness, a selection pressure for more but smaller seeds should operate similarly for all species. However, under stressful environmental conditions, selection pressure for larger seeds might override selection pressure for more but smaller seeds (Westoby et al 1992), because large-seeded species are known to have higher survivorship during establishment than small-seeded species (Westoby et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Seed weight increases with altitude in the Swiss Alps between related species but not among populations of individual species

2005

View full text Add to dashboard Cite

Seed weight is a crucial plant life history trait, determining establishment success and dispersal ability. Especially in stressful environments, larger seeds may be selected at the expense of seed number, because larger seeds have a better chance of giving rise to an established offspring. We tested the hypotheses that between related species-pairs and among populations of single species a similar trend for increasing seed weight with increasing altitude should be present. Firstly, we measured seed weights from 29 species-pairs, with one species occurring in lowland areas and a congeneric species from high altitudes. Seeds of the alpine species were 28±8% larger than seeds from lowland species (P<0.01). Compared to the related lowland species, 55% of the alpine species had heavier seeds, 3% (one species) had lighter, and 41% had seeds of approximately equal weight. Secondly, we compared seed weights among populations of four species from different habitats and with different life histories. Seeds from between 11 and 34 populations per species were sampled along altitudinal gradients of 800-1,500 m (ca. 800 m in Scabiosa lucida, ca. 1,000 m in Saxifraga oppositifolia, ca. 1,000 m in Epilobium fleischeri, and ca. 1,500 m in Carex flacca). In all the four species, we found no indication for heavier seeds at higher altitudes. Our results indicate a selection pressure for species with heavier seeds at higher altitude, but the trend does not seem to operate across all cases. Phylogenetic constraints may limit the correlation among altitude and seed weight, operating particularly against selection for larger seed size, the closer populations and species are related to each other.

show abstract

“…Seed mass is negatively correlated with the number of seeds produced and positively correlated with seedling survival (1)(2)(3)(4)(5). Smallseeded plants are considered to be efficient colonizers because they produce large numbers of seeds, whereas seedlings of large-seeded plants are thought to more effectively withstand resource restrictions and abiotic stresses.…”

mentioning

confidence: 99%

Control of seed mass byAPETALA2

Ohto

Fischer

Goldberg

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

355

366

View full text Add to dashboard Cite

Arabidopsis APETALA2 (AP2) encodes a member of the AP2͞EREBP (ethylene responsive element binding protein) class of transcription factors and is involved in the specification of floral organ identity, establishment of floral meristem identity, suppression of floral meristem indeterminancy, and development of the ovule and seed coat. Here, we show that loss-of-function ap2 mutations cause an increase in seed mass relative to that of wild-type seeds. Analysis of an allelic series of ap2 mutations showed that increases in seed mass corresponded with the severity of defects in flower structure, indicating that AP2 activity directly influences seed mass. Experiments with male-sterile plants and deflowered wild-type plants showed that reduced fertility of ap2 mutant plants due to abnormal flower structure accounted for only part of the increase in seed mass caused by strong ap2 mutant alleles. Reciprocal cross experiments showed that AP2 acts maternally to control seed mass. The maternal effect of AP2 on seed mass involves the regulation of both embryo cell number and cell size. We show further that ap2 mutations cause changes in the ratio of hexose to sucrose during seed development, opening the possibility that AP2 may control seed mass through its effects on sugar metabolism. Together, these results identify a role for AP2 in controlling seed mass.ap2 ͉ Arabidopsis ͉ seed size ͉ sugar metabolism S eeds of higher plants consist of three major components, each with a different genotype. The embryo that develops into the vegetative plant is diploid with a zygotic complement of genomes contributed by its parents. The endosperm, a tissue system that serves a nutritive role for the developing embryo and͞or germinating seedling, is triploid with two and one genome equivalents, respectively, contributed by the maternal and paternal parent. By contrast, the seed coat that surrounds the embryo and endosperm is strictly of maternal origin. Growth and development of the embryo, endosperm, and seed coat must be coordinated to produce the mature seed. Although seeds have been studied extensively, many aspects of seed development are not well understood, including the mechanisms that underlie seed size or mass.A critical factor in determining plant fitness is seed mass. Seed mass is negatively correlated with the number of seeds produced and positively correlated with seedling survival (1-5). Smallseeded plants are considered to be efficient colonizers because they produce large numbers of seeds, whereas seedlings of large-seeded plants are thought to more effectively withstand resource restrictions and abiotic stresses. Moreover, seed mass can vary intraspecifically in response to environmental cues, although little is known of the specific regulatory processes involved.Several factors that influence seed mass have been identified. For example, quantitative trait loci (QTL) that influence seed mass have been mapped in a number of crop plants (6)(7)(8)(9)(10)(11)(12)). An analysis of genetic factors affecting Arabidopsis seed mas...

show abstract

Comparative evolutionary ecology of seed size

Cited by 535 publications

References 34 publications

Differences in life history traits of relatedEpilobium species: Clonality, seed size and seed number

Differences in life history traits of relatedEpilobium species: Clonality, seed size and seed number

Seed weight increases with altitude in the Swiss Alps between related species but not among populations of individual species

Control of seed mass byAPETALA2

Contact Info

Product

Resources

About