{"title":"Density-dependent germination and the role of seed leachate","authors":"BRAD R. MURRAY","doi":"10.1111/j.1442-9993.1998.tb00748.x","DOIUrl":null,"url":null,"abstract":"<p><b>Abstract</b> While density dependence is a central issue in much of plant ecology, it is often overlooked during the crucial seed germination period of the plant life-cycle. Here, patterns of germination in relation to initial seed density for 12 phylogenetically-diverse perennial plant species are described from laboratory experiments. When each of the 12 species was analysed individually, seeds of <i>Alysicarpus rugosus, Callistemon citrinus, Eragrostis curvula and Panicum miliaceum</i> showed a significant decrease in the proportion of seeds germinating at high densities of conspecifics. A meta-analysis carried out by grouping 11 of the 12 species together revealed an overall significant effect for a decrease in the proportion of seeds germinating at high conspecific densities compared with low con-specific densities. Significant decreases in the proportion of seeds germinating are interpreted as risk reappraisal by seeds through dormancy in response to potentially hazardous conditions imposed by high density clusters of seeds all germinating at once. The four species that responded significantly to high densities individually were each treated at low densities with a leachate solution obtained from high density conspecifics. For <i>Alysicarpus rugosus</i> and <i>Panicum miliaceum</i>, this resulted in a significant decrease in the proportion of seeds germinating at simulated high densities implicating the leachate as a causative agent. Heterospecific effects were investigated similarly for <i>A. rugosus</i> and <i>E. curvula</i> by the addition of leachate from high density clusters of seeds of one species upon the other. Only <i>A. rugosus</i> decreased germination significantly through the addition of leachate. These results demonstrate the ability of seeds to predict environmental conditions of the habitat into which they will emerge in terms of potential competitive interactions from neighbouring seedlings.</p>","PeriodicalId":8663,"journal":{"name":"Austral Ecology","volume":"23 5","pages":"411-418"},"PeriodicalIF":1.6000,"publicationDate":"2006-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1111/j.1442-9993.1998.tb00748.x","citationCount":"82","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Austral Ecology","FirstCategoryId":"93","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/j.1442-9993.1998.tb00748.x","RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 82
Abstract While density dependence is a central issue in much of plant ecology, it is often overlooked during the crucial seed germination period of the plant life-cycle. Here, patterns of germination in relation to initial seed density for 12 phylogenetically-diverse perennial plant species are described from laboratory experiments. When each of the 12 species was analysed individually, seeds of Alysicarpus rugosus, Callistemon citrinus, Eragrostis curvula and Panicum miliaceum showed a significant decrease in the proportion of seeds germinating at high densities of conspecifics. A meta-analysis carried out by grouping 11 of the 12 species together revealed an overall significant effect for a decrease in the proportion of seeds germinating at high conspecific densities compared with low con-specific densities. Significant decreases in the proportion of seeds germinating are interpreted as risk reappraisal by seeds through dormancy in response to potentially hazardous conditions imposed by high density clusters of seeds all germinating at once. The four species that responded significantly to high densities individually were each treated at low densities with a leachate solution obtained from high density conspecifics. For Alysicarpus rugosus and Panicum miliaceum, this resulted in a significant decrease in the proportion of seeds germinating at simulated high densities implicating the leachate as a causative agent. Heterospecific effects were investigated similarly for A. rugosus and E. curvula by the addition of leachate from high density clusters of seeds of one species upon the other. Only A. rugosus decreased germination significantly through the addition of leachate. These results demonstrate the ability of seeds to predict environmental conditions of the habitat into which they will emerge in terms of potential competitive interactions from neighbouring seedlings.
期刊介绍：
Austral Ecology is the premier journal for basic and applied ecology in the Southern Hemisphere. As the official Journal of The Ecological Society of Australia (ESA), Austral Ecology addresses the commonality between ecosystems in Australia and many parts of southern Africa, South America, New Zealand and Oceania. For example many species in the unique biotas of these regions share common Gondwana ancestors. ESA''s aim is to publish innovative research to encourage the sharing of information and experiences that enrich the understanding of the ecology of the Southern Hemisphere.
Austral Ecology involves an editorial board with representatives from Australia, South Africa, New Zealand, Brazil and Argentina. These representatives provide expert opinions, access to qualified reviewers and act as a focus for attracting a wide range of contributions from countries across the region.
Austral Ecology publishes original papers describing experimental, observational or theoretical studies on terrestrial, marine or freshwater systems, which are considered without taxonomic bias. Special thematic issues are published regularly, including symposia on the ecology of estuaries and soft sediment habitats, freshwater systems and coral reef fish.
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