How does seed heteromorphism influence the life history stages of Atriplex sagittata (Chenopodiaceae)?
- 2 November 2005
- journal article
- Published by Elsevier BV in Flora
- Vol. 200 (6), 516-526
- https://doi.org/10.1016/j.flora.2005.06.003
Abstract
Atriplex sagittata is an annual, heterocarpic species producing three types of fruits, (i) dormant ebracteate (further termed type A), (ii) dormant bracteate (type B) and (iii) non-dormant bracteate (type C). In this study, we investigated populations grown from particular fruit types under different density regimes, and assessed their fate in particular life stages throughout a complete growing season. Differences in germination date among populations grown from seeds of the three fruit types were found, followed by differences in population density and plant size. Low population density and total biomass was recorded in populations of types A and B fruit (which are smaller and exhibit less germination), but the low density was not associated with faster growth of individual plants. Type C fruit, with bigger seeds and higher germinability, generated populations with higher densities and higher total biomass than populations generated from type A and B. There was a significant effect of plant density on dry weight of individual plants, regardless of the fruit type from which they were grown. Under both density regimes, plants grown from types A and B fruit were lighter than those grown from type C fruit. Plants grown from different fruit types produced dispersal units (fruits+bracteoles) of different mean weight which increased from A to B to C. However, the total fruit weight was not significantly different when plant size was used as a covariate. Maternal effect on seed germinability, exhibited by plants grown from the three fruit types, was not significant. However, a remarkable trend was found. Lower germination was recorded in type A and B fruits produced by plants which grew under higher densities. It is concluded that plants derived from different fruit types differ in growth characteristics and population parameters which can have pronounced effect on the life cycle and population regeneration in successive years.Keywords
This publication has 56 references indexed in Scilit:
- Dormancy and germination of heteromorphic achenes of Bidens frondosaFlora, 2004
- Effects of plant density and nutrient levels on fruit polymorphism in Atriplex sagittataOecologia, 1999
- Seed dispersal in Cakile edentula var. lacustris : decoupling the fitness effects of density and distance from the home siteOecologia, 1997
- The Influence of Initial Size on the Competitive Responses of Six Plant SpeciesEcology, 1995
- Heterocarpy and Seed Polymorphism in Ceratocapnos heterocarpa (Fumariaceae)International Journal of Plant Sciences, 1994
- Ethylene Production in Pea and Cocklebur Seeds of Differing VigourJournal of Experimental Botany, 1991
- Competition and Dormancy: A Reanalysis and ReviewThe American Naturalist, 1987
- Germination dimorphisms and parent-offspring conflict in seed germinationJournal of Theoretical Biology, 1986
- Seasonal Variation in the Seed Banks of Herbaceous Species in Ten Contrasting HabitatsJournal of Ecology, 1979
- Studies on the Ecological and Physiological Significance of Amphicarpy in Gymnarrhena micrantha (Compositae)American Journal of Botany, 1964