On the Analysis of Size-Dependent Reproductive Output in Plants

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

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Size at onset of maturity and size-dependent reproductive output of female and male spiny lobsters Jasus edwardsii (Hutton) (Decapoda, Palinuridae) in northern New Zealand

Journal of Experimental Marine Biology and Ecology ◽

10.1016/0022-0981(89)90076-2 ◽

1989 ◽

Vol 127 (3) ◽

pp. 229-243 ◽

Cited By ~ 29

Author(s):

A.B. MacDiarmid

Keyword(s):

New Zealand ◽

Reproductive Output ◽

Size Dependent ◽

Jasus Edwardsii ◽

Spiny Lobsters

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Size-dependent reproductive output in agricultural weeds

Canadian Journal of Botany ◽

10.1139/b91-061 ◽

1991 ◽

Vol 69 (3) ◽

pp. 442-446 ◽

Cited By ~ 75

Author(s):

B. K. Thompson ◽

J. Weiner ◽

S. I. Warwick

Keyword(s):

Reproductive Output ◽

Datura Stramonium ◽

Abutilon Theophrasti ◽

Sorghum Halepense ◽

Panicum Miliaceum ◽

Threshold Size ◽

Size Dependent ◽

Linear Relationships ◽

Apparent Relationship ◽

Agricultural Weeds

Data on reproductive and vegetative weights of individuals from five species of agricultural weeds (Apera spica-venti L., Datura stramonium L., Abutilon theophrasti Medic., Sorghum halepense (L.) Pers., and Panicum miliaceum L.) were used to test Weiner's (1988) model of linear size-dependent reproductive output in plants. In general, the populations showed strong evidence (P < 0.001) of linear relationships between reproductive and vegetative weight. Linearity was most pronounced in cases where size differences were primarily due to competition. Generally, the linear relationships were consistent from population to population within a species. Many of the populations also showed positive x-intercepts, indicating a threshold size for reproduction. However, there were a number of populations with no apparent relationship between reproductive and vegetative weight, with departures from linearity, or with positive y-intercepts (negative x-intercepts). Key words: reproductive weight, vegetative weight, agricultural weeds, size-dependent reproduction.

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An explanation for size-dependent reproductive allocation in Plantago major

Canadian Journal of Botany ◽

10.1139/b97-160 ◽

1998 ◽

Vol 76 (1) ◽

pp. 43-50 ◽

Cited By ~ 14

Author(s):

Edward G Reekie

Keyword(s):

Life History Theory ◽

Reproductive Output ◽

Direct Consequence ◽

Reproductive Allocation ◽

Reproductive Cost ◽

Trade Off ◽

Size Dependent ◽

Size Constraints ◽

Controlled Environments ◽

Size And Morphology

This study examined whether variation in reproductive allocation with size could be explained by differences in the trade-off between reproduction and growth. Seeds from 42 half-sibling families were collected from sites differing in mowing frequency and availability of light, nutrients, and water. Six seedlings from each family were grown in controlled environments and photoperiod manipulations were used to control reproduction. Mass of vegetative and reproductive plants of the same family were compared to assess the trade-off between reproduction and growth. Families collected from habitats with a tall canopy were larger and experienced a greater decrease in growth with reproduction than families from habitats where mowing maintained a short canopy. Reproductive output showed no relationship with size, while reproductive allocation (capsule mass to vegetative mass) decreased with size. This decrease may be a direct consequence of the increase in reproductive cost with size. The increase in cost can be partially explained by increased allocation to reproductive support structures; large individuals produce capsules on more elongate scapes and have a lower capsule to scape ratio. Differences in size and morphology among habitats are presumably the result of selection to avoid damage in mown sites and to avoid shade and ensure pollination in sites with a tall canopy and reduced wind movement.Key words: allometry, life-history theory, size constraints, reproductive effort, reproductive cost.

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Size-dependent reproductive output of female bagworms (Lepidoptera: Psychidae): Implications for inter-generational variations of population density.

Applied Entomology and Zoology ◽

10.1303/aez.2002.357 ◽

2002 ◽

Vol 37 (3) ◽

pp. 357-364 ◽

Cited By ~ 12

Author(s):

Marc Rhainds ◽

Cheng Tuck Ho

Keyword(s):

Population Density ◽

Reproductive Output ◽

Size Dependent ◽

Generational Variations

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Production and STEM examination of controlled-size silver clusters

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075488 ◽

1983 ◽

Vol 41 ◽

pp. 338-339

Author(s):

M. A. Listvan ◽

R. P. Andres

Keyword(s):

Cluster Size ◽

Metal Clusters ◽

Experimental Parameter ◽

Carbon Films ◽

Metal Species ◽

Silver Clusters ◽

Free Jet ◽

Size Dependent ◽

Cluster Properties ◽

Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

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Transfer Technique for Electron Microscopy of Membrance Filter Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005278x ◽

1974 ◽

Vol 32 ◽

pp. 554-555

Author(s):

Lawrence W. Ortiz ◽

Bonnie L. Isom

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Pore Size ◽

Membrane Filters ◽

Size Dependent

A procedure is described for the quantitative transfer of fibers and particulates collected on membrane filters to electron microscope (EM) grids. Various Millipore MF filters (Millipore AA, HA, GS, and VM; 0.8, 0.45, 0.22 and 0.05 μm mean pore size) have been used with success. Observed particle losses have not been size dependent and have not exceeded 10%. With fibers (glass or asbestos) as the collected media this observed loss is approximately 3%.

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Spindle scaling mechanisms

Essays in Biochemistry ◽

10.1042/ebc20190064 ◽

2020 ◽

Vol 64 (2) ◽

pp. 383-396

Author(s):

Lara K. Krüger ◽

Phong T. Tran

Keyword(s):

Cell Size ◽

Spindle Assembly ◽

Dependent Manner ◽

Post Translational Modification ◽

Size Dependent ◽

A Cell ◽

Chromosome Separation ◽

Spindle Elongation ◽

Protein Gradients ◽

Spindle Structure

Abstract The mitotic spindle robustly scales with cell size in a plethora of different organisms. During development and throughout evolution, the spindle adjusts to cell size in metazoans and yeast in order to ensure faithful chromosome separation. Spindle adjustment to cell size occurs by the scaling of spindle length, spindle shape and the velocity of spindle assembly and elongation. Different mechanisms, depending on spindle structure and organism, account for these scaling relationships. The limited availability of critical spindle components, protein gradients, sequestration of spindle components, or post-translational modification and differential expression levels have been implicated in the regulation of spindle length and the spindle assembly/elongation velocity in a cell size-dependent manner. In this review, we will discuss the phenomenon and mechanisms of spindle length, spindle shape and spindle elongation velocity scaling with cell size.

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