Seed mass is a trait that occupies a pivotal position in the ecology of a species. It links the ecology of reproduction and seedling establishment with the ecology of vegetative growth, strategy sectors that are otherwise largely disconnected (Grime et al., 1988; Shipley et al., 1989; Leishman and Westoby, 1992). There is a startling diversity of shapes and sizes of seeds among the plant species of the world. Seeds range from the dust seeds of the Orchidaceae and some saprophytic and parasitic species (around 10 6 g), across ten orders of magnitude to the double coconut Lodoicea seychellarum (104 g) (Harper et al., 1970). Within species, seed size typically spans less than half an order of magnitude (about fourfold: Michaels et al., 1988). Most within-species variation occurs within plant rather than among plants or populations (Michaels et al., 1988; Obeso, 1993; Vaughton and Ramsey, 1998), indicating environmental effects during development rather than genetic differences between mothers. This chapter is concerned with the differences in seed size among species, and the consequences for vegetation dynamics and community composition. During the last 10–15 years, there has been considerable progress in the ecology of seed mass. Unlike many other areas of comparative plant ecology, we have substantial published information from several different scales and research styles. As well as field experiments and demographic studies with a few species at a time, we have simple experiments with larger numbers of species (ten to 50), quantification of seed mass and its correlates in whole-vegetation types (hundreds of species) and tests of consistency across different continents. The wide-scale quantification began as early as Salisbury (1942) and Baker (1972), but has been much added to and consolidated over the past 10 years (e.g. Mazer, 1989, 1990; Leishman and Westoby, 1994a; Leishman et al., 1995; Eriksson and Jakobsson, 1998). The work spanning large numbers of species is complementary to detailed experiments involving only a few species, giving a stronger sense of how widely the results from particular experiments can be generalized. Much of the literature examines how natural selection on seed size might be influenced by various environmental factors. In this context, it is at first glance surprising that seed size varies within communities across a remarkable five to six orders of magnitude (Leishman et al., 1995; Fig. 2.1). Further, there is strong overlap of seed-size distributions between quite different habitats. Within the temperate zone,

/pdf/the-evolutionary-ecology-of-seed-size-399ewiogxb.pdf

The Evolutionary ecology of seed size

Several taxa of the Australian Proteaceae have invaded South African fynbos and require costly management programmes to bring under control. Banksia spp. have been introduced only recently to fynbos regions. The invasive potential of Banksia ericifolia (Proteaceae) was investigated by comparing its recruitment potential with that of an indigenous proteaceous shrub, Leucadendron laureolum. Both species are overstorey shrubs that are killed by fire and rely on canopy-stored seeds (serotiny) for recruitment. Eight year old B. ericifolia shrubs produced an average of 16 500 seeds per plant, which is thirty times more than the average of 570 seeds produced by 10 year old L. laureolum shrubs. The seed bank of B. ericifolia was not only larger than that of L. laureolum (1098 vs 525 viable seeds m−2 projected canopy cover), but also considerably larger than that described for the species in its native environment (200–330 seeds m−2 in a 9 year old stand north of Sydney). Leucadendron laureoleum released most of its seed a few days after the cones were burnt, whereas seed release in B. ericifolia was spread over 12 weeks. The seeds of B. ericifolia had lower wingloading and fall rates than L. laureolum and were dispersed over greater distances. The relative seedling growth rates of the two species were very similar (0.03 g per day), but below-ground biomass was greater and proteoid roots were more developed in B. ericifolia seedlings than in L. laureolum after 100 days. Four year old B. ericifolia plants growing in the field had attained over twice the height of indigenous pro-teoids and accumulated up to 10 times the fresh biomass of L. xanthoconus, a species which is ecologically similar to L. laureolum. The Bioclimatic Prediction System (BIOCLIM) was used to create a bioclimatic profile of B. ericifolia and identify climatically suitable areas in the Cape Province. Results show that its potential distribution covers most fynbos areas in the southwestern Cape. It is concluded that B. ericifolia has the potential to be highly invasive in fynbos.

The invasive potential of Australian banksias in South African fynbos: A comparison of the reproductive potential of Banksia ericifolia and Leucadendron laureolum

Part I. Introduction: 1. Mediterranean-type climate (MTC) ecosystems and fire 2. Fire and the fire regime framework 3. Fire related plant traits Part II. Regional Patterns: 4. Fire in the Mediterranean basin 5. Fire in California 6. Fire in Chile 7. Fire in the Cape region of South Africa 8. Fire in southern Australia Part III. Comparative Ecology, Evolution and Management: 9. Fire-adaptive trait evolution 10. Fire and the origins of Mediterranean-type vegetation 11. Plant diversity and fire 12. Alien species and fire 13. Fire management of Mediterranean landscapes 14. Climate, fire and geology in the convergence of Mediterranean-type climate ecosystems References Index.

/pdf/fire-in-mediterranean-ecosystems-ecology-evolution-and-2wv8dufrqn.pdf

Fire in Mediterranean Ecosystems: Ecology, Evolution and Management

1. We hypothesized that in Mediterranean plant communities seedling survival of different species during the drought period would be related to their ability to use below-ground resources, particularly water and nitrogen.

2. For 5 years we studied under field conditions the summer seedling survival of 11 dominant species of a Spanish Mediterranean shrubland. We related seedling survival of the different species to their seed size and root allocation estimated as the slope of the function root biomass vs log shoot biomass. We used δ13C for the estimation of water-use efficiency and δ15N and nitrogen concentration to determine the sources of nitrogen utilized. We correlated these variables with root allocation.

3. Seedling survival of the different species was positively correlated with root allocation and seed size. Root allocation was also positively correlated with seed size. δ15N and nitrogen concentration were also positively correlated with root allocation, but δ13C was not.

4. Under the relatively moist conditions occurring during summer 1996, higher root allocation was associated with the use of nitrogen from more nitrogen saturated microsites.

https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2435.1999.00309.x

Seedling survival of Mediterranean shrubland species in relation to root:shoot ratio, seed size and water and nitrogen use

summary
We examined the importance of seed size in the early establishment of seedlings of four cotyledonous species restricted to nutrient-impoverished soils in south-western Australia. Experimentally removing cotyledons from seedlings increased mortality and reduced root-penetration, growth rate and final weight of plants after 12 wk, in proportion to seed size. The impact of removal of the cotyledons was least in the smallest-seeded, Eucalyptus loxophleba Benth., grown in the more fertile of two soils, and greatest in the largest-seeded, Hakea psilorrhyncha R. M. Barker, whose growth was otherwise unaffected by soil type. In the smallest-seeded species, cotyledon content of most mineral nutrients increased over time, especially in the more fertile soil, while chlorophyll content showed some decrease by the end of the experiment. In the other species, most nutrients (especially N, P, K and Cu in the less fertile soil) were translocated from the cotyledons to the growing plant, and chlorophyll content declined markedly. The translocated N, P, K, Mg and Cu in these species made up a substantial part of the total plant content by 12 wk after germination, while total Ca and Fe tended to increase in the cotyledons via substantial soil uptake. The results indicate, contrary to reports for some other species, that the cotyledons have an important nutritional function in the early establishment of seedlings in these species. The results also show that, in the larger-seeded species, young seedlings rely to a greater extent on nutrient support from the cotyledons than from the soil. We propose that large seeds might be an adaptation for enhancing establishment in nutrient-poor soils.

Seed/cotyledon size and nutrient content play a major role in early performance of species on nutrient-poor soils

(1) Seedling development under nutrient-deficient conditions was investigated for five bradysporous members of the Proteaceae to test the hypothesis that large seed size and high embryo nutritional quality reflect the outcome of selection favouring propagules suited for establishment in infertile soils characteristic of those natural environments dominated by members of the Proteaceae. (2) Seeds of Protea lorifolia, Protea cynaroides, Leucadendron laureolum, Hakea sericea and Banksia laricina were germinated and grown on nutrient-deficient sand for 200 days. Every forty days ten seedlings of each species were harvested to determine growth, allocation patterns and nutrient use. Seedling parts were dried, weighed and analysed for N, P, K, Ca and Mg. . (3) Seedlings of all Proteaceae species were able to survive prolonged periods of nutrient scarcity irrespective of seed size. (4) Rapid germination of Proteaceae seeds does not appear to be a significant means of increasing seedling fitness. (5) Seed mass was positively correlated with seedling size. (6) No correlation between relative growth rates and seed size was found. (7) Seeds of members of the Proteaceae show selective storage of specific nutrients (N and P) such that seed chemical composition is unbalanced for optimum seedling growth. These elements complement the rich sources of cations Ca,Mg and K found in soils of post-fire environments when maximal recruitment of proteoid species occurs.

Influence of seed size and quality on seedling development under low nutrient conditions in five Australian and South African members of the Proteaceae.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

J. S. Pate

Author Tools

Chat about Author

Papers

Influence of seed size and quality on seedling development under low nutrient conditions in five Australian and South African members of the Proteaceae.