Electrophoretic and allometric variation in burdock (Arctium spp.): hybridization and its ecological implications

1985 ◽  
Vol 63 (7) ◽  
pp. 1255-1261 ◽  
Author(s):  
C. David Rollo ◽  
J. D. MacFarlane ◽  
B. S. Smith
Keyword(s):  
Population Dynamics ◽  
Isoelectric Focusing ◽  
Seed Predation ◽  
Parental Species ◽  
Seed Viability ◽  
Combined Effects ◽  
Alkaline Phosphatases ◽  
Ecological Implications ◽  
Insect Seed Predation ◽  
Insect Predation

Allometric variation and insect seed predation among Arctium minus, A. lappa, and two possible hybrids were quantified. All four biotypes were also examined using isoelectric focusing, and differences among their proteins were found for alkaline phosphatases, leucine amino peptidases, esterases, and peroxidases. The allometric and electrophoretic results indicated that hybridization between A. minus and A. lappa is very common. The implications for the population dynamics of Arctium are discussed. The parental species are probably maintained by the combined effects of differential insect predation on the seeds, differential dispersal of seeds, and reduced seed viability in hybrids.

Combined effects of deer, mice and insect seed predation on the reproductive success of a Mediterranean shrub

2017 ◽  
Vol 21 ◽  
pp. 45-54 ◽  
Author(s):  
Xavier Lecomte ◽  
Maria C. Caldeira ◽  
Miguel N. Bugalho ◽  
José M. Fedriani
Keyword(s):  
Reproductive Success ◽  
Seed Predation ◽  
Deer Mice ◽  
Combined Effects ◽  
Insect Seed Predation ◽  
Mediterranean Shrub

scholarly journals Contrasting effects of the onset of spring on reproductive success of Arctic-nesting geese

The Auk ◽  
2019 ◽  
Vol 137 (1) ◽  
Author(s):  
Bart A Nolet ◽  
Kees H T Schreven ◽  
Michiel P Boom ◽  
Thomas K Lameris
Keyword(s):  
Population Dynamics ◽  
Late Onset ◽  
The Other ◽  
Second Phase ◽  
Combined Effects ◽  
Negative Effects ◽  
Early Snowmelt ◽  
The One ◽  
Winter Flocks ◽  
Breeding Propensity

Abstract Breeding output of geese, measured as the proportion of juveniles in autumn or winter flocks, is lower in years with a late onset of spring in some species, but higher in at least one other species. Here we argue that this is because the timing of spring affects different stages of the reproductive cycle differently in different species. Because the effects on 2 different stages are opposite, the combined effects can result in either a positive or a negative overall effect. These stages are the pre-laying, laying, and nesting phase on the one hand; and the hatchling, fledgling, and juvenile phase on the other hand. The first phase is predominantly positively affected by an early snowmelt, with higher breeding propensity, clutch size, and nest success. The second phase in contrast is negatively affected by early snowmelt because of a mismatch with a nutrient food peak, leading to slow gosling growth and reduced survival. We argue that recognition of this chain of events is crucial when one wants to predict goose productivity and eventually goose population dynamics. In a rapidly warming Arctic, the negative effects of a mismatch might become increasingly important.

scholarly journals Isoelectric focusing of human liver alkaline phosphatase

1970 ◽  
Vol 118 (2) ◽  
pp. 299-302 ◽  
Author(s):  
A. L. Latner ◽  
Mary E. Parsons ◽  
A. W. Skillen
Keyword(s):  
Alkaline Phosphatase ◽  
Density Gradient ◽  
Isoelectric Focusing ◽  
Isoelectric Point ◽  
Human Liver ◽  
Sucrose Density Gradient ◽  
Ph Gradient ◽  
Alkaline Phosphatases ◽  
Carrier Ampholytes

1. Isoelectric focusing of human liver alkaline phosphatase in a sucrose density gradient with LKB Ampholine as carrier ampholytes is described. 2. Problems due to the chelating properties of the ampholytes and the pH gradient were examined. 3. A reactivation procedure to counter these effects was devised that can probably be used for other alkaline phosphatases. 4. The isoelectric point of human liver alkaline phosphatase was found to be pH3.9.

Postdispersal seed predation and seed viability in forest soils: implications for the regeneration of tree species in Ethiopian church forests

2009 ◽  
Vol 48 (2) ◽  
pp. 461-471 ◽  
Author(s):  
Alemayehu Wassie ◽  
Tesfaye Bekele ◽  
Frank Sterck ◽  
Demel Teketay ◽  
Frans Bongers
Keyword(s):  
Forest Soils ◽  
Seed Predation ◽  
Tree Species ◽  
Seed Viability ◽  
Ethiopian Church

Predispersal seed predation and population dynamics in the perennial understorey herb Actaea spicata

2003 ◽  
Vol 81 (11) ◽  
pp. 1058-1069 ◽  
Author(s):  
Heléne Fröborg ◽  
Ove Eriksson
Keyword(s):  
Population Dynamics ◽  
Seed Predation ◽  
Seedling Recruitment ◽  
Deciduous Forest ◽  
Transition Probabilities ◽  
Coniferous Forest ◽  
Perennial Herb ◽  
Seed Predator ◽  
Predispersal Seed Predation ◽  
The Impact

Predispersal seed predation by a moth larva, Eupithecia immundata Leinig & Zeller (Geometridae), and its impact on population dynamics of the perennial herb Actaea spicata L. were studied during 7 years in deciduous and mixed coniferous forest populations in southeastern Sweden. Twelve population matrix models were constructed based on transition probabilities among six stage classes in the populations. The fraction of seeds consumed varied between 21% and 80% but was not significantly correlated with seed production. Experimental seed addition compensating for seed losses caused by the seed predator resulted in increased seedling emergence in one of the populations. Population growth rate was positive (λ > 1) in 1 of 6 years in the deciduous forest population and in 2 of 6 years in the mixed coniferous forest population. Survival among reproductive individuals contributed most strongly to λ in both populations. In some years, the projected λ changed from positive to negative values because of seed loss caused by E. immundata. However, results suggest that seed predation did not affect λ to any large extent, despite a considerable seed predation. This study is one of the rare efforts to estimate the impact of seed predation on population dynamics of perennial plants.Key words: Actaea spicata, demography, population dynamics, predispersal seed predation, seedling recruitment.

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