scholarly journals Nematodes in relation to plant growth, IV. Pratylenchus penetrans (Cobb) on orchard trees.

1962 ◽  
Vol 10 (4) ◽  
pp. 286-296 ◽  
Author(s):  
H. Hoestra ◽  
M. Oostenbrink
Keyword(s):  
Plant Growth ◽  
Shoot Growth ◽  
Sandy Soils ◽  
Good Evidence ◽  
Small Populations ◽  
Pratylenchus Penetrans ◽  
Experimental Conditions ◽  
Nematode Density ◽  
Large Populations ◽  
Considerable Damage

The damage caused by Pratylenchus penetrans in orchards is discussed. In 2 experimental fields containing 4 varieties of apple, there was good evidence of a decrease in yield with increased nematode density before apple seedlings were planted. Heavy nematode infestations reduced shoot growth by more than 50%. A concentration of 100 nematodes per 300 ml. of soil may cause considerable damage. The process of infestation and symptoms of nematode attack under field and experimental conditions are discussed. In clean cultivated orchards on light sandy soils there are often large populations in the roots and very small populations in the soil but on heavier soils, the converse is true. Hoestra & Oostenbrink conclude without doubt that P. penetrans is an important cause of replant problems in orchards. H.R. W. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Quanti-Qualitative Response of Swiss Chard (Beta vulgaris L. var. cycla) to Soil Amendment with Biochar-Compost Mixtures

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 307
Author(s):  
Angela Libutti ◽  
Anna Rita Rivelli
Keyword(s):  
Plant Growth ◽  
Beta Vulgaris ◽  
Interactive Effect ◽  
Organic Amendments ◽  
Experimental Conditions ◽  
Total N ◽  
Qualitative Response ◽  
Positive Effects ◽  
Swiss Chard ◽  
Two Factors

In recent years, soil addition with organic amendments, such as biochar and compost, has gained attention as an effective agronomic practice to sustain soil fertility, enhance plant growth and crop yield. Well known are the positive effects of compost on yield of a wide crop varieties, while both positive and negative responses are reported for biochar Therefore, the aim of the study was to verify the effect of biochar mixed with three types of compost on quanti-qualitative response of Swiss chard (Beta vulgaris L. cycla), a leafy green vegetable rich in dietary antioxidants, largely consumed worldwide. A factorial experiment in pots with two factors, including biochar (without biochar and with biochar from vine pruning residues) and compost (without compost, with compost from olive pomace, with vermicompost from cattle manure, and with compost from cattle anaerobic digestate), was setup. Two growth cycles were considered, and a set of quantitative (height of plants, number, area and fresh weight of leaves) and qualitative parameters (carotenoids, chlorophyll, total N, and NO3−content of leaves) were analyzed. Biochar decreased plant growth and NO3− leaf content; on the contrary, it increased total N leaf content, while compost improved all the considered parameters. The interactive effect of biochar and compost was evident only on total N and NO3− leaf content. In our experimental conditions, the compost showed to be the best option to improve Swiss chard growth and increase the content of phytopigments, while the biochar-compost mixtures did not produce the expected effect.

scholarly journals Increased Resistance of Bt Aspens to Phratora vitellinae (Coleoptera) Leads to Increased Plant Growth under Experimental Conditions

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e30640 ◽  
Author(s):  
Joakim Hjältén ◽  
E. Petter Axelsson ◽  
Thomas G. Whitham ◽  
Carri J. LeRoy ◽  
Riitta Julkunen-Tiitto ◽  
...  
Keyword(s):  
Plant Growth ◽  
Experimental Conditions ◽  
Phratora Vitellinae

scholarly journals Effect of Plant Growth Regulators on Shoot Growth of a Columnar Type Apple Tree

2003 ◽  
Vol 2 (2) ◽  
pp. 97-100 ◽  
Author(s):  
Manabu Watanabe ◽  
Akira Suzuki ◽  
Sadao Komori ◽  
Hidetugu Sato
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Shoot Growth ◽  
Apple Tree

scholarly journals Unexpected heterozygosity in an island mouflon population founded by a single pair of individuals

2006 ◽  
Vol 274 (1609) ◽  
pp. 527-533 ◽  
Author(s):  
Renaud Kaeuffer ◽  
David W Coltman ◽  
Jean-Louis Chapuis ◽  
Dominique Pontier ◽  
Denis Réale
Keyword(s):  
Genetic Diversity ◽  
Wild Population ◽  
Ovis Aries ◽  
Stochastic Simulations ◽  
Single Pair ◽  
Small Populations ◽  
Short Period ◽  
Large Populations ◽  
History Of ◽  
Over Time

In population and conservation genetics, there is an overwhelming body of evidence that genetic diversity is lost over time in small populations. This idea has been supported by comparative studies showing that small populations have lower diversity than large populations. However, longitudinal studies reporting a decline in genetic diversity throughout the whole history of a given wild population are much less common. Here, we analysed changes in heterozygosity over time in an insular mouflon ( Ovis aries ) population founded by two individuals in 1957 and located on one of the most isolated locations in the world: the Kerguelen Sub-Antarctic archipelago. Heterozygosity measured using 25 microsatellite markers has actually increased over 46 years since the introduction, and exceeds the range predicted by neutral genetic models and stochastic simulations. Given the complete isolation of the population and the short period of time since the introduction, changes in genetic variation cannot be attributed to mutation or migration. Several lines of evidence suggest that the increase in heterozygosity with time may be attributable to selection. This study shows the importance of longitudinal genetic surveys for understanding the mechanisms that regulate genetic diversity in wild populations.

Unequal Voting

2019 ◽  
pp. 175-192
Author(s):  
James Lindley Wilson
Keyword(s):  
Electoral College ◽  
Small Populations ◽  
Political Equality ◽  
Voting Power ◽  
Political Inequality ◽  
The Us ◽  
Large Populations ◽  
Us Senate

This chapter assesses how the inequalities in voting power involved in the US Senate and in the Electoral College used to elect the president violate the requirements of political equality. The Senate comprises two senators from each state. States with large populations get the same number of votes in the Senate as do states with small populations. Because the states vary considerably in population, there are large inequalities in how many citizens are represented by a senate delegation. This unequal representation of individuals in the Senate constitutes objectionable political inequality. The Senate is thus unjustifiably undemocratic. This conclusion has implications for the election of the US president, as the Electoral College process for such election tracks what the chapter argues is the malapportionment of the Senate. This inequality, too, is objectionable, and it should be eliminated. The reasons for a more egalitarian election of the president are all the more urgent given that the inequalities in the Senate are much more constitutionally entrenched, and thus likely to remain. The election of the president should mitigate that inequality rather than exaggerate it.

scholarly journals All roads lead to growth: imaging-based and biochemical methods to measure plant growth

2019 ◽  
Vol 71 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Justyna Jadwiga Olas ◽  
Franziska Fichtner ◽  
Federico Apelt
Keyword(s):  
Plant Growth ◽  
Growth Rates ◽  
Shoot Growth ◽  
Comprehensive Description ◽  
Vegetative Plant ◽  
Biochemical Methods

We provide a comprehensive description and comparison of the various imaging and non-imaging-based techniques used to measure vegetative plant shoot growth and suggest a terminology for growth rates.

scholarly journals Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish

2014 ◽  
Vol 281 (1790) ◽  
pp. 20140370 ◽  
Author(s):  
Dylan J. Fraser ◽  
Paul V. Debes ◽  
Louis Bernatchez ◽  
Jeffrey A. Hutchings
Keyword(s):  
Genetic Variation ◽  
Habitat Fragmentation ◽  
Population Size ◽  
Brook Trout ◽  
Small Populations ◽  
Adaptive Genetic Variation ◽  
Genetic Population ◽  
Fragmented Populations ◽  
Large Populations ◽  
Adaptive Differentiation

Whether and how habitat fragmentation and population size jointly affect adaptive genetic variation and adaptive population differentiation are largely unexplored. Owing to pronounced genetic drift, small, fragmented populations are thought to exhibit reduced adaptive genetic variation relative to large populations. Yet fragmentation is known to increase variability within and among habitats as population size decreases. Such variability might instead favour the maintenance of adaptive polymorphisms and/or generate more variability in adaptive differentiation at smaller population size. We investigated these alternative hypotheses by analysing coding-gene, single-nucleotide polymorphisms associated with different biological functions in fragmented brook trout populations of variable sizes. Putative adaptive differentiation was greater between small and large populations or among small populations than among large populations. These trends were stronger for genetic population size measures than demographic ones and were present despite pronounced drift in small populations. Our results suggest that fragmentation affects natural selection and that the changes elicited in the adaptive genetic composition and differentiation of fragmented populations vary with population size. By generating more variable evolutionary responses, the alteration of selective pressures during habitat fragmentation may affect future population persistence independently of, and perhaps long before, the effects of demographic and genetic stochasticity are manifest.

PLANT GROWTH REGULATOR ACTIVITY OF SOLUBLE HUMIC COMPLEXES

1984 ◽  
Vol 64 (2) ◽  
pp. 225-228 ◽  
Author(s):  
G. CACCO ◽  
G. DELL’AGNOLA
Keyword(s):  
Biological Activity ◽  
Plant Growth ◽  
Key Words ◽  
Growth Regulators ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Good Evidence ◽  
High Concentration ◽  
Stem Curvature ◽  
Cytokinin Bioassays

Auxin and cytokinin bioassays were performed to test the biological activity of soluble humic complexes (SHC). "Pea split stem curvature" (auxin test) and "cucumber" tests (cytokinin test) did not show any quantifiable biological activity of SHC. On the contrary, "cress test" and "senescence test" offered good evidence of a hormonal-like activity 100 times lower than that of IAA (10 mg IAA∙g−1 SHC) and 10 times lower than that of N6 BA (100 mg N6 BA∙g−1 SHC). At a high concentration of SHC, toxic effects were evident, indicating the presence of inhibitory substances which counteracted the hormone-like activity of humic complexes. Key words: Plant growth regulators, soluble humic complexes

scholarly journals Biomorpher: Interactive evolution for parametric design

2018 ◽  
Vol 16 (2) ◽  
pp. 144-163 ◽  
Author(s):  
John Harding ◽  
Cecilie Brandt-Olsen
Keyword(s):  
Parametric Design ◽  
Performance Criteria ◽  
Evolutionary Design ◽  
Parametric Modelling ◽  
Small Populations ◽  
Design Exploration ◽  
Wide Range ◽  
Large Populations ◽  
Modelling Environment ◽  
User Motivation

Combining graph-based parametric design with metaheuristic solvers has to date focused solely on performance-based criteria and solving clearly defined objectives. In this article, we outline a new method for combining a parametric modelling environment with an interactive Cluster-Orientated Genetic Algorithm. In addition to performance criteria, evolutionary design exploration can be guided through choice alone, with user motivation that cannot be easily defined. As well as numeric parameters forming a genotype, the evolution of whole parametric definitions is discussed through the use of genetic programming. Visualisation techniques that enable mixing small populations for interactive evolution with large populations for performance-based optimisation are discussed, with examples from both academia and industry showing a wide range of applications.

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