Light is critical in determining plant structure and functioning in dune ecosystems, which are characterised by high incident and reflected radiation. Light variations demand great plasticity of the photosynthetic apparatus. This study assessed the phenotypic plasticity of foredune species by analysing their light response and dark recovery curves measured under field conditions. We also addressed the question how coexisting species, structurally distinct, differed in their photochemical efficiency in response to short-term changes in light. Finally, we examined how the varying intensity of stressors operating along a dune gradient affected responses to light. The species differed in light use strategies but showed similar patterns of the dark recovery. Species differences in photochemistry varied seasonally, with species being winter specialists, summer specialist or generalists. Some aspects of their photochemistry varied significantly along the gradient. Unexpectedly, other traits did not vary as predicted. For example, changes in light efficiency of plants along the gradient were not consistent with assumed directional changes in the severity of stressors. The different light use strategies observed in coexisting species did not conform to the prediction that stressors constrain the range of possible functional designs in harsh environments. However, the species followed very similar patterns of post-illumination recovery, which suggests that evolutionary pressures might be acting to maintain similar recovery mechanisms. Our results indicated that dune gradients might be nondirectional, which determines unpredictable patterns of variation in leaf traits along the dune gradient. Seasonal differences in the relative performance may allow species to coexist where otherwise one species would exclude the other., R. Bermúdez, R. Retuerto., and Obsahuje bibliografii
We report on the discovery of new four variable stars in the Cassiopea constellation from the archive of the HALZ telescope, operated by the TOPTEC team at Horní Halže, near Klášterec nad Ohří, Czech Republic. The stars are catalogued as UCAC4 718-108144 (23h 04m 16.383s +53° 29’ 44.78”), UCAC4 725-101725 (23h 09m 27.87s +54° 51’ 23.27”), UCAC4 725-101699 (23h 09m 19.53s +54° 57’ 57.18”), UCAC4 722-105015 (23h 10m 42.4s +54° 14’ 33.33”). From the light curve, the stars should be a HADS - type variable (UCAC4 718- 108144), an EW - type variable (UCAC4 725-101725), an EA - type variable (UCAC4 725-101699) and an ELL - type variable (UCAC4 722-105015). We registered these stars in the CzeV catalogue as new variable stars CzeV709, CzeV710, CzeV711 and CzeV715. and Objevili jsme čtyři nové proměnné hvězdy v souhvězdí Kasiopea z archivu dalekohledu HALZ, který je provozován zaměstnanci centra TOPTEC v Horní Halži, která se nachází v Krušných horách poblíž Klášterce nad Ohří v České republice. Nově objevené hvězdy jsou katalogizovány jako UCAC4 718-108144 (23h 04m 16.383s +53° 29’ 44.78”), UCAC4 725-101725 (23h 09m 27.87s +54° 51’ 23.27”), UCAC4 725-101699 (23h 09m 19.53s +54° 57’ 57.18”), UCAC4 722-105015 (23h 10m 42.4s +54° 14’ 33.33”). Podle světelné křivky jsme určili typ proměnných hvězd jako HADS - typ (UCAC4 718-108144), EW - typ (UCAC4 725-101725), EA - typ (UCAC4 725-101699) a ELL - typ (UCAC4 722-105015). Zaregistrovali jsme tyto hvězdy v katalogu CzeV jako nové proměnné hvězdy CzeV709, CzeV710, CzeV711 a CzeV715.
We report the discovery of a new variable star during the search for new exoplanets in the Centaurus constellation from the FRAM telescope archive, operated by the FRAM team at Los Leones, near Malargüe, Argentina. The star is catalogued as GSC 08630-01117 (11h 36m 10s -53° 12’ 15.04”). From the light curve the star should be an ELL-type variable. We computed the period P = 0.6311 ± 0.0002 days. The maximum is 13.07 ± 0.02 mag and minimum is 13.22 ± 0.02 mag (in the Johnson V filter) with an amplitude of about 0.15 mag. We registered this star in the CzeV catalogue and in the VSX catalogue as new variable star CzeV603. Several transits of known exoplanets were observed by the FRAM telescope. These observations show the ability to detect new exoplanets using the FRAM telescope. and Objevili jsme novou proměnnou hvězdu v souhvězdí Kentaura v rámci mise hledání nových exoplanet z archivu dalekohledu FRAM, který je řízen skupinou FRAM z Los Leones poblíž Malargüe v Argentině. Tato hvězda má označení GSC 08630-01117 (11h 36m 10s -53° 12’ 15,04”). Tato proměnná hvězda je typu ELL. Vypočítali jsme periodu P= 0,6311 ± 0,0002 dne. Maximum má 13,07 ± 0,02 mag a minimum 13,22 ± 0,02 mag (ve Johnsonově V filtru)s amplitudou okolo 0,15 mag. Zaregistrovali jsme tuto hvězdu v českém CzeV katalogu a v americkém katalogu VSX jako proměnnou hvězdu CzeV603. Dalekohled FRAM pozoroval také několik tranzitů známých exoplanet. Tato pozorování ukazují na schopnost detekce nových neznámých exoplanet z archivu dalekohledu FRAM.