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Self-isolation and insect pollination in the primitive angiosperms: New evaluations of older hypotheses (1987)

Bernhardt, Peter ; Thien, Leonard B.

Springer

Plant systematics and evolution 156 (1987), S. 159-176

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ISSN: 1615-6110

Keywords: Arecales ; Cyclanthales ; Dilleniaceae ; Magnoliidae ; Angiosperm evolution ; bees ; beetles ; dichogamy ; dicliny ; insects ; protandry ; protogyny

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract A review of the literature, compiled over the past 40 years suggests new directions for theories discussing the evolution of reproductive isolation and entomophily in angiosperms. Data on breeding systems suggests that the protoangiosperms may have developed gametophytic self-incompatibility. Protogyny is probably ancestral to protandry and herkogamy. Although the proto-flowers were bisexual wide variation in the number of sexual organs within proto-flowers probably led to labile sexuality and early trends towards dicliny. Beetle-pollination in extant relicts appears too specialized to represent an ancestral condition. Rather, the proto-flowers may have been generalist entomophiles incorporating some beetles,Plecoptera, thrips, micropterigid moths and proto-dipterans into their fluctuating spectra of opportunistic pollinators. Bee-pollination is probably polyphyletic in origin evolving repeatedly from angiosperms showing these generalist syndromes. There is still no correlation between primitive bees (especiallyColletidae) and the relictual angiosperms. Pollen that is usually retained within the anthers following dehiscence and the presence of staminal filaments and styles characterizes most of the flowers of those relictual angiosperms pollinated by specialized, modernApoidea.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00936071

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Particle Size Analysis of Some Difficult Measurable SystemsPaper presented at the 4th meeting “Granulometrie” 1985 at Dresden. (1986)

Hoffmann, Brigitte ; Bernhardt, Claus

Weinheim : Wiley-Blackwell

Particle and Particle Systems Characterization 3 (1986), S. 163-167

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ISSN: 0934-0866

Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology

Notes: Knowledge of the granulometric behaviour of dispersed systems is vital for a full and complete characterisation. Despite the variety of methods and devices which have been developed for this purpose, difficulties frequently arise in the practical determination of particle size distribution. In this paper it is shown, by means of examples, how measurements for surface modified and porous particles can be influenced by the behaviour of the material, and which approaches exist to obtain accurate values by taking this into account.

Additional Material: 7 Ill.