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

Znaleziono wyników: 9

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:  photosynthetic active radiation
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
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

High light inducible leaf antioxidants improve UV tolerance in greenhouse grown tobacco

100%
Majer P., Hideg E.
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
|
2013
|
tom 94
|
nr 2
2

Seedling survival and dynamics of upper timberline in Central Apennines

84%
Catorci A., Scapin W., Tardella F. M., Vitanzi A.
Polish Journal of Ecology
|
2012
|
tom 60
|
nr 1
Despite several studies on the timberline dynamics in Europe were carried out in the last decades, very few papers refer to mountain areas where the timberline is composed of broadleaved trees, and no research was conducted on the dynamics of Apennine beech timberline in relation to seedling survival. The research aim was to analyse the beech wood timberline dynamics in the central Apennines, with reference to seedling survival. Furthermore, factors affecting seedling survival were identified. To assess the forest ecotone dynamics, vegetation layer cover, rock fragment cover and information about forest management and krummholz occurrence were collected in sampling plots placed over 1,600 m a.s.l., on north-facing slopes. The beech seedlings occurring in Brachypodium genuense-dominated stands above the timberline were counted and monitored along two growing seasons. Soil temperature, soil moisture, and photosynthetically active radiation available for seedlings (PHAR) in grasslands above timberline were measured. The research outputs indicate that timberline is not a natural boundary and that there is no evidence of its extension upwards. The greatest number of beech seedlings was recorded in late spring. The one-year mortality rate ranged from 71 to 100%. None of the seedlings still alive in the early autumn of the first year were recorded in the following spring. The competitive exclusion by Brachypodium genuense individuals, which limit the incident PHAR, and the low soil moisture during summer, were identified as the main factors that account for the high mortality of seedlings and affect beech regeneration above timberline. The effect of competition is probably intensified by the lack of pioneer shrubs which could otherwise serve as nurse plants for beech seedlings and protect them from browsing by wild ungulates. Thus, both the current and the past land use may be considered as driving forces in timberline dynamics. Probably, also the trend of global warming, that in the Mediterranean and sub-Mediterranean climatic context would determine the increase of summer drought stress, could worsen the effect of competitive exclusion of beech seedlings, so that it can be hypothesized that the expansion upwards of the upper timberline in the Apennines could be totally blocked.
3
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Comparison of primary productivity estimates in the Baltic Sea based on the DESAMBEM algorithm with estimates based on other similar algorithms

84%
Stramska M., Zuzewicz A.
Oceanologia
|
2013
|
tom 55
|
nr 1
4

Evaluation of primary production of phytoplankton based on chlorophyll delayed fluorescence in sea water

84%
Zvalinsky V. I., Bekasova O. D., Kaczmarek S., Kosakowska A.
Oceanologia
|
1990
|
tom 28
5

Phytoplankton diversity and biomass during winter with and without ice cover in the context of climate change

84%
Lenard T., Wojciechowska W.
Polish Journal of Ecology
|
2013
|
tom 61
|
nr 4
Most scenarios of the predicted climate change in Europe imply that the increasing temperature trend will be maintained in winter seasons. The presence or absence of the ice cover in winter can impact on the functioning of lake ecosystems. The research was carried out in two mesotrophic and dimictic lakes in winter with and without ice cover. The biomass and phytoplankton and its composition was analysed with reference to physical factors (PAR and temperature). The research proved that poor thermal-light conditions under the ice/snow cover favoured the development of nanoplanktonic species from the genus Cryptomonas (Cryptophyta) or Stephanodiscus (Bacillariophyceae), whereas microplanktonic species of dinoflagellates, diatoms or green algae prevailed during the ice-free winter. The highest phytoplankton biomass and species richness were recorded during ice-free winter, which affected a higher Shannon-Wiener diversity index and evenness. It has been shown that the mild winter creates good conditions for the development of phytoplankton species characteristic for the mixing periods. The lack of inverse thermal stratification during winter can lead to disturbance in the functioning of the water ecosystems throughout the year.
6

Influence of humic acids [HA], DCMU, and light on the ultraweak luminescence [UL] of Characeae cells

84%
Milczarek I., Jaskowska A., Golebiowska D.
Electronic Journal of Polish Agricultural Universities. Series Environmental Development
|
2003
|
tom 06
|
nr 2
Ultraweak luminescence (UL) within the visible range accompanies physiological processes taking place in Native non-stressed Nitellopsis Obtusa cells. Intensity of UL emission is several times higher than the intensity of an environmental medium. The influence of Humic acid (HA), diuron-urea herbicide (DCMU) and photosynthetic active radiation (PAR) on UL intensity and spectral composition for algae cells was investigated. Measurements were made both in neutral and reactive media. An artificial pond water (APW) served as a neutral medium. Algae cells in APW were used as the control samples. Concentrations of specific chemical agents were equal to 8·10-2mg·mL-1, 4.2·10-2 mmol·L-1 for HA and DCMU, respectively, whereas PAR intensity reached 900 µE·s-1·m-2. The influence of HA and light on UL intensity was studied.
7

The effect of light quality on organogenesis of Hyacinthus orientalis L. in vitro

67%
Bach A., Swiderski A.
Acta Biologica Cracoviensia. Series Botanica
|
2000
|
tom 42
|
nr 1
Shoot and bulb induction of hyacinths under the influence of varying light treatments (blue, green, yellow, red, far-red and UV irradiation) was studied in long-term in vitro cultures. Leaf explants were cultivated on solid MS medium containing sucrose or glucose (90, 180 or 360 mM). The light as well as the types and concentrations of carbohydrates affected regeneration. Blue light stimulated growth and development of adventitious shoots and buds regardless of carbohydrate type, while the highest number of bulbs was obtained under red or white light and darkness as well as low and moderate concentrations of sucrose in medium. On average, 360 mM glucose yielded the highest proliferation rate of adventitious bulbs, followed by 180 mM sucrose. Blue light and UV irradiation promoted development of chlorophylls. Blue light also increased the total amount of anthocyanins. Far-red light reduced chlorophyll content.
8

Wpływ dawki azotu i fotosyntetycznie aktywnej radiacji (PAR) na występowanie mszycy zbożowej (Sitobion avenae F.) w jęczmieniu jarym

59%
Lozowicka B., Wolejko E., Loboda T., Pietkiewicz S.
Progress in Plant Protection
|
2010
|
tom 50
|
nr 3
The aim of a pot experiment was to study the effect nitrogen fertilization applied under different levels of PAR (Photosynthetically Active Radiation) on aphids’ occurrence in spring barley. The following experiment factors were taken into consideration: three spring barley cultivars (Maresi, Poldek and Rasbet), three levels of PAR (1 – full, 0.5 and 0.25) and three nitrogen doses (0.5, 1.0 and 1.5 g N/pot). The result of presented study showed that with increasing levels of fertilization and PAR the number and percentage of barley plants infested by aphids significantly increased.
9

Porownanie wartosci ochronnej zboz jarych i bobiku dla koniczyny czerwonej. Czesc I. Wartosc ochronna i produkcyjnosc zboz jarych i bobiku

59%
Zajac T., Witkowicz R.
Acta Agraria et Silvestria. Series Agraria
|
1997
|
tom 35
121-132
Field experiments were conducted in the Prusy Research Station (near Kraków). Red clover was grown as an undersown plant with spring cereals (barley, wheat, and triticale) and field bean or without a supporting plant (control). Productivity and supporting capacity of spring cereals and field bean were compared. Red clover established in all supporting plants in spite of different degree of shading and their productivity. Taking into account the economical value of the yield, the supporting plants could be arranged in a following order: wheat > barley > triticale, and field bean. For these reasons growing red clover without supporting plants is not recommended. The leaf area of canopy of a supporting plant was not the only factor determining the amount of photosynthetic active radiation absorbed by the undersown plant during the periods of the most intesive shading.
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.