A comparative study of germination characteristics in a local flora
TL;DR: Under constant temperature conditions, the majority of grasses, legumes and composites germinated over a wide range of temperature, and the same feature was evident in species of ubiquitous or southern distribution in the British Isles.
Abstract: seeds for immediate germination. Of the 403 species examined, 158 failed to exceed 10% germination but 128 attained values greater than 80%. Germination was high in the majority of grasses and low in many annual forbs and woody species. With respect to initial germinability, major families could be arranged in the series Gramineae > Compositae > Leguminosae = Cyperaceae > Umbelliferae. Many small-seeded species were able to germinate immediately after collection and seeds of these species were often elongated or conical and had antrorse hairs or teeth on the dispersule. High initial germinability was conspicuous among the species of greatest abundance in the Sheffield flora. (4) In the majority of species, germination percentage increased during dry storage; this effect was most marked in small-seeded species. Among the seventy-five species which responded to chilling, some germinated at low temperature in darkness whilst others were dependent upon subsequent exposure to light or to higher temperature or to both. Responses to chilling were characteristic of the Umbelliferae. In all of the legumes examined, rapid germination to a high percentage was brought about by scarification. (5) Under the experimental conditions, all of the annual grasses showed the potential for rapid germination. High rates were also observed in many of the annual forbs and perennial grasses. Low rates of germination occurred in the majority of sedges, shrubs and trees, and were particularly common in species of northern distribution in Britain. Rapid germination was characteristic of the species of greatest abundance in the Sheffield flora. Rate of germination showed a progressive decline with increasing seed weight, and, with some exceptions, there was a positive correlation between rate of germination and the relative growth rate of the seedling. (6) In sixteen species, germination in the light was found to be dependent upon exposure to diurnal fluctuations in temperature. Under constant temperature conditions, the majority of grasses, legumes and composites germinated over a wide range of temperature, and the same feature was evident in species of ubiquitous or southern distribution in the British Isles. A requirement for relatively high temperature was apparent in sedges, in plants of northern distribution and in a majority of the marsh plants. The range of constant temperatures conducive to germination tended to be wider in grassland plants than in woodland species. Rapid germination over a wide range of temperature occurred in many of the species which attain greatest abundance in the Sheffield flora. 0022-0477/81/1100-1017 $02.00 (?1981 Blackwell Scientific Publications
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01 Sep 2011
TL;DR: In this paper, the Ecosystem Concept is used to describe the Earth's Climate System and Geology and Soils, and the ecosystem concept is used for managing and sustaining ecosystems.
Abstract: I. CONTEXT * The Ecosystem Concept * Earth's Climate System * Geology and Soils * II. MECHANISMS * Terrestrial Water and Energy Balance * Carbon Input to Terrestrial Ecosystems * Terrestrial Production Processes * Terrestrial Decomposition * Terrestrial Plant Nutrient Use * Terrestrial Nutrient Cycling * Aquatic Carbon and Nutrient Cycling * Trophic Dynamics * Community Effects on Ecosystem Processes * III. PATTERNS * Temporal Dynamics * Landscape Heterogeneity and Ecosystem Dynamics * IV. INTEGRATION * Global Biogeochemical Cycles * Managing and Sustaining Ecosystem * Abbreviations * Glossary * References
3,086 citations
TL;DR: It is concluded that the major evolutionary force determining the nature of the seed bank is the selective advantage derived from mechanisms of seed dormancy and germination which allow seedlings to evade the potentially-dominating effects of established plants.
Abstract: SUMMARY (1) Measurements have been made of seasonal variation in the density and composition of the reservoir of germinable seeds present in surface (0-3 cm) soil samples collected at 6-weekly intervals from ten ecologically-contrasted sites in the Sheffield region. (2) The procedure was not designed to provide a complete assessment of the seed flora, and the methods were found to be ineffective in recovering germinable seeds of those species (e.g. Endymion non-scriptus, Viola riviniana, several Umbelliferae) in which there is only a brief interval between fulfilment of a chilling requirement and the onset of germination. (3) The techniques adopted were particularly suitable for the detection of persistent seed banks (i.e. those in which some of the component seeds are at least 1 year old), and also allowed recognition of species in which there is a transient accumulation of detached germinable seeds during the summer. (4) Comparison of the results obtained for populations of the same species in different types of habitat suggests that seasonal variation in seed number is a function of the species rather than of the environment. (5) It is concluded that the major evolutionary force determining the nature of the seed bank is the selective advantage derived from mechanisms of seed dormancy and germination which allow seedlings to evade the potentially-dominating effects of established plants. (6) From the data collected in this study, four types of seed bank (Types I-IV) have been recognized, and an attempt has been made to assess their ecological significance. (7) The transient seed banks (Types I and II) are adapted to exploit the gaps created by seasonally-predictable damage and mortality in the vegetation, whilst the persistent seed bank (Type IV) confers the potential for regeneration in circumstances where disturbance of the established vegetation is temporally and/or spatially unpredictable. A second type of persistent seed bank (Type III) has characteristics intermediate between those of Types I and IV, and contains some seeds which germinate soon after release and others which are more persistent in the soil. (8) A feature of the results was the lack of a general correspondence between the species-composition of the seed flora and that of the associated vegetation. At certain sites, substantial persistent seed banks were detected for species which were either extremely scarce or did not occur at all in the established vegetation. (9) Both transient and persistent types of seed banks were represented at each of the ten sites; this is consistent with the hypothesis that complementary mechanisms of regeneration are involved in the maintenance of floristic diversity.
1,537 citations
Book•
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TL;DR: This work has shown clear trends in the dispersal and regeneration of seeds in disturbed areas, and these trends are likely to continue into the next decade.
Abstract: What determines the number and size of the seeds produced by a plant? How often should it reproduce them? How often should a plant produce them? Why and how are seeds dispersed, and what are the implications for the diversity and composition of vegetation? These are just some of the questions tackled in this wide-ranging review of the role of seeds in the ecology of plants. The authors bring together information on the ecological aspects of seed biology, starting with a consideration of reproductive strategies in seed plants and progressing through the life cycle, covering seed maturation, dispersal, storage in the soil, dormancy, germination, seedling establishment, and regeneration in the field. The text encompasses a wide range of concepts of general relevance to plant ecology, reflecting the central role that the study of seed ecology has played in elucidating many fundamental aspects of plant community function.
1,382 citations
TL;DR: The susceptibility of the indigenous community to invasion was strongly related to the availability of bare ground created, but greatest success occurred where disturbance coincided with eutrophication.
Abstract: A long—term field experiment in limestone grassland near Buxton (North Derbyshire, United Kingdom) was designed to identify plant attributes and vegetation characteristics conducive to successful invasion. Plots containing crossed, continuous gradients of fertilizer addition and disturbance intensity were subjected to a single—seed inoculum comprising a wide range of plant functional types and 54 species not originally present at the site. Several disturbance treatments were applied; these included the creation of gaps of contrasting size and the mowing of the vegetation to different heights and at different times of the year. This paper analyzes the factors controlling the initial phase of the resulting invasions within the plots subject to gap creation. The susceptibility of the indigenous community to invasion was strongly related to the availability of bare ground created, but greatest success occurred where disturbance coincided with eutrophication. Disturbance damage to the indigenous dominants (particularly Festuca ovina) was an important determinant of seedling establishment by the sown invaders. Large seed size was identified as an important characteristic allowing certain species to establish relatively evenly across the productivity—disturbance matrix; smaller—seeded species were more dependent on disturbance for establishment. Successful and unsuccessful invaders were also distinguished to some extent by differences in germination requirements and present geographical distribution.
1,061 citations
27 Sep 2012
TL;DR: This updated Test Guideline 430 provides an in vitro procedure allowing the identification of non-corrosive and corrosive substances and mixtures in accordance with UN GHS.
Abstract: Other methods and guidelines not included in this publication
may be judged to be appropriate in testing chemicals in certain
scientifi c, legal, and administrative contexts.The OECD Council Decision on Mutual Acceptance of Data
(12th May 1981; C[81]30) affi rms that data generated in one
country in accordance with the OECD Test Guidelines – and additionally in accordance with the OECD Principles of Good Laboratory Practice – should be accepted in OECD countries for purposes
of assessment and other uses relating to protection of man and the
environment. The full text of this Decision and the OECD Principles of Good Laboratory Practice may be found in the Appendix
to the OECD Guidelines for Testing of Chemicals.
851 citations
Cites background from "A comparative study of germination ..."
...6 L = D 0 3 (50%) (19) maturation may be necessary (18, 19) POST A (Black Knapweed) fields, roadsides, (14, 19) (14) (19) 4 (97%) (18) germination inhibited by darkness (19) (5, 22, 26) open habitats (16, 19) no special treatments (5, 14, 26) Inula helenium P 1 - 1....
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...17 L = D 0 3 (50%) (19) germination not affected by irradiance (18, 19) POST A, D, F 7 (English Daisy) grassland, arable fields, (4, 19) (14) (4) 11 (100%) (18) no special treatments (4, 14) (4) turf (16, 19) Centaurea cyanus A 4....
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..., considering their taxonomic diversity in the plant kingdom, their distribution, abundance, species specific life-cycle characteristics and region of natural occurrence, to develop a range of responses (8) (10) (16) (17) (18) (19) (20)....
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...9 L = D 0 5 (50%) cold stratification (7, 14, 18, 19) POST (Japanese Hedge-parsley) disturbed areas, (14, 19) (14) (1, 19) (19) maturation may be necessary (19) (5) hedgerows, pastures germination inhibited by darkness (1, 19) (16, 19) no special treatments (5) ASTERACEAE Bellis perennis P 0....
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...2 L = D 0 4 (50%) (19) germination inhibited by darkness (17, 18, 19) POST (Big Hawkbit) fields, roadsides, (14, 19) (14) (19) 7 (80%) (18) no special treatments (5, 23) (5, 22, 23) disturbed areas (16, 19) Rudbeckia hirta B, P 0....
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References
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Book•
01 Jan 1979
TL;DR: In this paper, the authors present plant strategies in the established phase and the regenerative phase in the emerging phase, respectively, and discuss the relationship between the two phases: primary strategies and secondary strategies.
Abstract: PLANT STRATEGIES. Primary Strategies in the Established Phase. Secondary Strategies in the Established Phase. Regenerative Strategies. VEGETATION PROCESSES. Dominance. Succession. Co-Existence. References. Index.
5,687 citations
TL;DR: This chapter discusses the evolution of Dispersal Organs in General, and discusses the role of dispersal strategy and the Biocoenosis in this process.
Abstract: I. Introduction.- A. The Place of Dispersal in the Chain of Life.- B. Limitations and Objections.- C. History and General Literature.- II. General Terminology.- III. The Units of Dispersal.- Vegetative Parts in Dispersal and False Vivipary.- IV. The Relation Between Flowers, Seeds and Fruits.- A. Seed and Fruit.- B. Morphological Fruit Systems.- C. Morphological Interaction Between Fruit and Flower.- 1. General.- 2. Position.- 3. Monovuly and Monospermy.- 4. Inferiority and the Calyx.- D. Inadequacy of Current Fruit Terminology.- V. Ecological Dispersal Classes, Established on the Basis of the Dispersing Agents.- A. General.- B. Invertebrates.- C. Fishes and Ichthyochory.- D. Reptiles and Saurochory.- E. Birds and Ornithochory.- 1. Epizoochory by Birds.- 2. Synzoochorous Bird Diaspores.- 3. Endozoochory.- Non-adapted Diaspores.- Adapted Diaspores.- The Syndrome of Bird Diaspores.- Oil-containing Fruits.- Remarks on Evolution.- Mimesis (Imitative Seeds).- F. Mammals and Mammaliochory.- 1. General.- 2. Dyszoochory and Rodents.- 3. Accidental Endozoochory.- 4. Adaptive Endozoochory.- Ungulates.- Bats and Chiropterochory.- Primates.- Various Mammals.- G. Ants and Myrmecochory.- H. Wind and Anemochory.- 1. General.- 2. Dust Diaspores.- 3. Balloons.- 4. Plumed (Comose) Diaspores.- 5. Winged Diaspores.- 6. Tumbleweeds.- 7. Wind-Ballists (Anemoballists).- J. Water and Hydrochory.- 1. General.- 2. Rain Wash (Ombrohydrochory).- 3. Rain-Ballists.- 4. Submerged Transport in Water.- 5. Floating Diaspores.- K. Epizoochory, Transport on the Outside of Animals in General.- 1. Diverse Origins.- 2. Trample Burrs.- 3. Water Burrs.- 4. Burrs and Other Adhesives Above Ground Level.- 5. Other Spiny Fruits.- L. Autochory, Dispersal by the Plant Itself.- 1. General.- 2. Active Ballists.- 3. Passive Ballists.- 4. Creeping Diaspores.- M. Barochory, Dispersal by Weight Only.- N. Retrospective View.- VI. Dispersal Strategy and the Biocoenosis.- A. Atelochory.- 1. General.- 2. Synaptospermy.- 3. Basicarpy.- 4. Geocarpy.- B. Polychory and Attendant Phenomena.- 1. General.- 2. Heterodiaspory.- 3. Tachyspory.- C. Concluding Remarks on Synecology.- 1. Deserts.- 2. The Rain Forest.- 3. Epiphytes.- 4. The Arctic.- 5. Island Floras.- 6. Plant Sociology and Dispersal.- 7. Coordinated Dispersal.- VII. Establishment.- A. General.- B. Fixation.- C. Vivipary.- D. Germination.- 1. General Importance.- 2. Span of Life and Dormancy.- 3. Influence of Dispersing Agents and Other Stimuli.- VIII. The Evolution of Dispersal Organs in General.- A. Aims.- B. Isosporous Pteridophytes.- C. Heterosporous Pteridophytes with Free Megaspores.- D. Pteridosperms.- E. Gymnosperms (or Pre-Angiosperms).- F. Angiosperms.- 1. The Seed.- 2. The Seed Escaped from Angiospermy.- 3. The Sarcotesta Maintained in Conventional Fruits.- 4. Arilloids.- 5. Pulpa.- 6. The Pericarp Fruit.- Shift of Function.- Autonomous Cycles.- Further Evolutionary Influences and Processes.- IX. Ecological Developments in Leguminous Fruits.- X. Dispersal and the Evolution of Grasses.- A. Comparison with Cyperaceae.- B. Return to Gramineae (i.c. Oryzeae).- C. Bambusoid Grasses.- D. Bamboos.- E. Open Plains and Higher Grasses.- F. Some More Remarks on Awns and on Establishment.- G. Retrospective Views.- XI. Man and His Plants in Relation to Dispersal.- References.- Index of Scientific Plant Names.- Index of Scientific Animal Names.
1,679 citations
"A comparative study of germination ..." refers background in this paper
...INTRODUCTION The results of many comprehensive studies (Ridley 1930; Salisbury 1942; Isely 1947; Ross-Craig 1948-74; Baker 1972; van der Pijl 1972; Hubbard 1976; Lhotska & Chrtkova 1978) show clearly that flowering plants differ considerably with respect to the number, size, shape and dispersal…...
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Book•
01 Mar 1984
TL;DR: The classification of families and abbreviations of Pteridophyta, Gymnospermae, Angiospermaes, Dicotyledones, Monocotylingones and other life forms are summarized in this monograph.
Abstract: Foreword by Professor A. G. Tansley Preface to the first edition Acknowledgements Preface to the second edition Preface to the third edition Synopsis of classification Artificial key to families Signs and abbreviations Pteridophyta Gymnospermae Angiospermae Dicotyledones Monocotyledones Bibliography Authorship of families Note on life forms Glossary Index.
1,430 citations
Book•
01 Jan 1930
TL;DR: The dispersal of plants throughout the world, The Dispersal of Plants throughout the World, the authors, is a popular topic in the field of plant propagation, especially in agriculture.
Abstract: The dispersal of plants throughout the world , The dispersal of plants throughout the world , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
1,284 citations
1,265 citations
"A comparative study of germination ..." refers background in this paper
...Although the role of impermeable seed coats under field conditions is still uncertain (Ballard 1973), there can be little doubt that this characteristic is often conducive to delayed germination and incorporation into persistent seed banks. A further insight into the possible ecological significance of the hard seed coats of legumes is provided by studies such as those of Hamly (1932) and Hagon & Ballard (1969) and Hagon (1971), which have shown that permeability depends upon the condition of the strophiole, the only point of entry of water into the unscarified seeds of many legumes....
[...]
...Although the role of impermeable seed coats under field conditions is still uncertain (Ballard 1973), there can be little doubt that this characteristic is often conducive to delayed germination and incorporation into persistent seed banks. A further insight into the possible ecological significance of the hard seed coats of legumes is provided by studies such as those of Hamly (1932) and Hagon & Ballard (1969) and Hagon (1971), which have shown that permeability depends upon the condition of the strophiole, the only point of entry of water into the unscarified seeds of many legumes. More suggestive still are the results of Quinlivan (1961, 1968) and Quinlivan & Millington (1962), which have established that in some Australian legumes permeability of the strophiole can be increased under field conditions by diurnal temperature fluctuations of the magnitude commonly experienced by buried seeds lying on or close to a soil surface devoid of vegetation....
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