Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 10

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  functional trait
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Effect of long-term abandonment and spring grazing on floristic and functional composition of dry grasslands in a Central Apennine farmland

100%
Catorci A., Casaretti S., Gatti R.
Polish Journal of Ecology
|
2013
|
tom 61
|
nr 3
Semi-natural dry grasslands host some of the most valuable habitats in Europe, due to their biodiversity heritage. Nevertheless, a strong decline in their extension, due to the cessation of traditional management, has been observed in the last decades. The aim of the study was to assess plant community changes due to abandonment and the effect of spring grazing in sub-Mediterranean dry grasslands, focusing on the plant functional traits involved in this turnover. The study area is located in the central Apennines (Italy), where grasslands were grazed by sheep in late winter and spring until 1980 and are nowadays abandoned. Relevés sampled (using the Braun-Blanquet method) in different years, namely in 1976–1980 (grazed pasture) and again in 2010 (abandoned pasture) were compared. Results indicated that abandonment leads to the increase of species richness. Traits and strategies indicator sets were: therophyte for the grazed pasture; geophytes, flower palatability, early flowering strategy, clonal ability and presence of storage organs for the abandoned ones. Traits related to low levels of stress (tolerance strategies) are heavily reduced in grazed systems, and thus the functional composition of plant community is mostly characterised by traits promoting avoidance strategies. In abandoned conditions a higher number of species can co-exist thanks to the micro-scale variation of soil features and niche diversification. The research findings also revealed grazing timing as a key factor for understanding changes of plant functional trait patterns and spring grazing as a threat for orchid species.
2

Polymorphism A/C in exon 7 of the bovine estrogen receptor alpha (ERalpha) gene and its association with functional and milk production traits in Red-and-White cattle

84%
Szreder T., Oprzadek J., Zelazowska B., Dymnicki E., Zwierzchowski L.
Animal Science Papers and Reports
|
2011
|
tom 29
|
nr 4
Due to the functions that estrogens play in the regulation of reproduction, development of mammary gland, growth and differentiation of cells, estrogen receptors and their genes are considered candidates for molecular markers of production and functional traits in farm animals. In this study,using the SSCP and DNA sequencing, we found a novel single nucleotide polymorphism (SNP) in the coding region of the estrogen receptor α (ERα) gene – the A/C transversion at position 323,396 (relative to the start of transcription site), in exon 7, that could be also detected with RFLP-CfrI.This mutation causes the amino acid replacement – Asparatic acid/Alanine in the ligand-binding domain (LBD) of the receptor.The ERα A/C (RFLP-CfrI) genotypes were estimated in a cohort of 489 cattle of different breeds,including 355 Red-and-White cows. Association was studied between ERα genotype and dairy production traits (milk yield and composition) and functional traits (reproduction, length of productive life). The results showed that ERα A/C genotype affected significantly only a few traits of interest: protein and fat content in milk, sex of calves born. No associations were detected between ERα genotype and milk yield and reproduction traits of Red-and-White cows.
3

Impact of LEP and LEPR gene polymorphisms on functional traits in Polish Holstein-Friesian cattle

84%
Komisarek J.
Animal Science Papers and Reports
|
2010
|
tom 28
|
nr 2
Five single nucleotide polymorphisms in leptin and leptin receptor genes were analysed for their possible impact on estimating breeding values for somatic cell count score (SCS) in milk, longevity and reproductive traits. Used were 309 active Polish Holstein-Friesian bulls. The LEP-C(-963)T,LEP-Y7F, LEP-R25C, LEP-A80V, and LEPR-T945M genotypes were identified using the PCRRFLP method. For linked leptin mutations, the additional haplotype analysis was performed. The results obtained suggest that three polymorphisms of bovine LEP gene may be associated with nonreturn rate in cows. The most significant effect was found for LEP-A80V. Moreover, the LEPRT945M mutation seemed to be related to the age at first insemination.
4

Variations of leaf economic spectrum of eight dominant plant species in two successional stages under contrasting nutrient supply

84%
Mao W., Li Y.-L., Zhao X.-Y., Zhang T.-H., Liu X.-P.
Polish Journal of Ecology
|
2016
|
tom 64
|
nr 1
Leaf functional traits are indicators of both plant community and ecosystem responses to environmental factors and can thus increase our capacity to understand ecosystem processes and community assembly due to climate change. The variation in leaf functional traits between succession stages in Horqin Sandy Land is caused by soil nutrient content and by intrinsic biological characteristic of species, but the effects are different. Leaf economic spectra were assessed for seven leaf traits of eight species from early and advanced stages of succession. Species from early succession stages are Agriophyllum squarrosum (L.) Moq., Corispermum macrocarpum Bge., Setaria viridis (L.) Beauv. and Pennisetum centrasiaticum Tzvel., and species from advanced successional stages are Chenopodium acuminatum Willd., Chloris virgate Swartz, Digitaria sanguinalis (L.) Scop. and Leymus secalinus (Georgi) Tzvel. All these species were grown in a greenhouse experiment under two contrasting nutrient supplies including high nutrient level (N , with 20 g of nutrient addition) and low nutrient level (N-, with no added nutrients). As expected, the resource uptake strategies of the species were affected by soil fertilization addition. Leaf nitrogen content (LNC), leaf phosphorus content (LPC), and photosynthetic capacity per unit leaf area (Aarea) significantly increased at high nutrient level but LPC is more dramatically changed than others leaf traits. Leaf life span (LLS) and specific leaf area (SLA) did not show similar tendency with succession stage. At the same nutrient level, LES still shows different pattern between the early and the advanced succession stages. Species from early succession stages have higher LPC and Aarea, compared to species from advanced stages. Species from early succession stage also tend to have higher SLA and higher LNC than at the advanced succession stage. The LLS did not show any clear changes with succession process. These results provide evidence that LES shift along the succession process is mainly caused by intrinsic biological characteristic of species.
5

Response of Sphagnum testate amoebae to drainage, subsequent re-wetting and associated changes in the moss carpet – results from a three year mesocosm experiment

84%
Koenig I., Schwendener F., Mulot M., Mitchell E. A. D.
Acta Protozoologica
|
2017
|
tom 56
|
nr 3
6

Assessment of floristic diversity, functional composition and management strategy of North Adriatic pastoral landscape (Croatia)

67%
Vitasovic Kosic I., Tardella F. M., Ruscic M., Catorci A.
Polish Journal of Ecology
|
2011
|
tom 59
|
nr 4
European semi-natural calcareous grasslands are species-rich ecosystems, considered as priority habitats by the European Union (92/43/EEC Directive) and judged worthy of conservation. They are in strong decline in extension and are threatened by abandonment throughout Europe. It is known that grasslands management (grazing, mowing) acts as driving force in plant community diversity, which in turn is an important conservation aim of European environmental policies. The area of current pastoral landscape (about 1000 ha) of the North Adriatic (Ćićarija, Croatia) was studied in order: 1/ to understand which factors drive floristic differentiation – environmental features and/or grassland management conditions, 2/ to identify indicator species sets linked to those factors and 3/ to appraise the effects of management type on the coenological and functional composition of indicator species. 73 phytosociological releves were carried out; for each of them field data (altitude, aspect, slope and land form), productivity measurements and information on grassland management were collected. Redundancy analysis (RDA) identified a productivity-related soil moisture gradient as the environmental driving force of grassland floristic differentiation. Indicator species analysis (ISA) detected the indicator species sets related to environmental features and management type. The results indicate that undergrazing and the lack of periodic mowing are responsible for the higher total variance of floristic data set explained by environmental parameters rather than by management (use/not use). For the same reasons, the variations that emerged from comparison of the functional characteristics of the indicator species of grazing and of mowing (avoidance strategy, life form, and storage organs) proved more important than those observed in comparing used and abandoned grasslands. The management system adopted (grazing or mowing) appears in turn to be conditioned by the soil moisture/productivity gradient.
7

Functional differentiation of Central Apennine grasslands under mowing and grazing disturbance regimes

67%
Catorci A., Ottaviani G., Ballelli S., Cesaretti S.
Polish Journal of Ecology
|
2011
|
tom 59
|
nr 1
This research dealt to two grasslands potentially developing the same vegetation type because sited in the same environmental contest (bioclimate, substratum, soil, slope, altitude) but under diverse management regimes (grazing and mowing) for many decades. The evidenced differentiation between the two pastoral vegetations can be attributed to disturbance type and the statistical functional analysis performed through seven plant traits (prostrate form, early flowering, storage organs, clonal ability, basal meristems, chemical defences and hairs), revealed the distinguishing patterns. Discriminant analysis pointed out typical biological attributes for each disturbance conditions, while from correlation analysis emerged different possible traits combinations which do not follow the previous traits separation. Such outcomes are explainable because both grazing and mowing provoke aboveground phytomass removal, although grazing is a selective pressure, while mowing gives to all the species the same development chances. It is reasonable to conclude that convergent strategies within the two systems are possible and frequent.
8

Differential effects of grazing on plant functional traits in the desert grassland

67%
An H., Li G.
Polish Journal of Ecology
|
2014
|
tom 62
|
nr 2
Plant functional traits are linked with environmental factors, individuals and ecosystem structure and functions as plants respond and adapt to the environment. Here, the whole-plant traits (plant height and plant biomass), leaf morphological (leaf area, leaf dry mass and specific leaf area) and chemical traits (leaf carbon, nitrogen, phosphorus contents, C/N and N/P ratio) of six dominant species (Cynanchum komarovii Al, Euphorbia esula Linn, Glycyrrhiza uralensis Fisch, Lespedeza potaninii Vass, Agropyron mongolicum Keng and Stipa breviflora Griseb) were studied in the desert grassland of China, with a grazing experiment including four grazing intensity (0.00, 0.45, 1.00, 1.50 sheep ha–1). The effect of grazing on leaf morphological traits were significant for the six dominant species, while the effects on whole-plant traits were highly significant for S. breviflora, A. mongolicum, G. uralensis, L. potaninii and C. komarovii. Three of the six species (S. breviflora, A. mongolicum and L. potaninii) decreased in plant height (PH) with increasing grazing intensity, while specific leaf area (SLA) and leaf N (Nmass) showed the opposite trend. The whole-plant traits were significantly positively correlated with leaf dry mass (LM), but significantly negatively correlated with leaf nitrogen and phosphorus contents. The first principal component analysis (PCA) axis corresponding to plant size (PH and PB) and leaf size (LA and LM), while the second axis of PCA to leaf chemical traits (Nmass, P, C and N/P). Variations of plant traits in response to grazing were mainly explained by size trait and chemical traits. The functional traits cannot be the only basis for predicting plant species in response to grazing, and a functional analysis of the trade-off between plant traits is also needed.
9

Genetic background of performance and functional traits in mink

67%
Rozempolska-Rucinska I.
Electronic Journal of Polish Agricultural Universities. Series Animal Husbandry
|
2004
|
tom 07
|
nr 2
The material comprised the data on 12 generations of animals collected from the breeding documentation of a standard mink reproduction farm. Reproduction and conformation traits covariance components were estimated by means of the REML method based on a multitrait animal model, using the DMU software package. Estimated heritability coefficients demonstrate a low additive effect of animal on the discussed traits. Particularly low values of this index were related to litter sizes at birth and at weaning. As to the conformation traits, the heritability coefficients remained between 0.116 and 0.218. Additive maternal effect on the level of reproduction and conformation traits was also estimated in the studies. The value of the parameter was about twice as high as the genetic variability resulting from the additive value of an individual and ranged from 0.037 to 0.202.
10

Investigation of major gene for milk yield, milking speed, dry matter intake, and body weight in dairy cattle

67%
Karacaoren B., Kadarmideen H. N., Janss L. L. G.
Journal of Applied Genetics
|
2006
|
tom 47
|
nr 4
The main aim of this study was to determine if there exist any major gene for milk yield (MY), milking speed (MS), dry matter intake (DMI), and body weight (BW) recorded at various stages of lactation in first-lactation dairy cows (2543 observations from 320 cows) kept at the research farm of the Swiss Federal Institute of Technology between April 1994 and April 2004. Data were modelled based a simple repeatability covariance structure and analysed by using Bayesian segregation analyses. Gibbs sampling was used to make statistical inferences on posterior distributions; inferences were based on a single run of the Markov chain for each trait with 500 000 samples, with each 10th sample collected because of the high correlation among the samples. The posterior mean (±SD) of major gene variance was 2.61 (±2.46) for MY, 0.83 (±1.26) for MS, 4.37 (±2.34) for DMI, and 2056.43 (±665.67) for ВW. Highest posterior density regions for 3 of the 4 traits did not include 0 (except MS), which supported the evidence for major gene. With additional tests for agreement with Mendelian transmission probabilities, we could only confirm the existence of a major gene for MY, but not for MS, DMI, and BW. Expected Mendelian transmission probabilities and their model fits were also compared.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.