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EN
Desiccation tolerance, the ability to lose virtually all of its free intracellular water and then restore normal function when rehydrated, is one of the most remarkable features of bryophytes. The aim of the study was to determine the resistance of two species of Plagiomnium undulatum (Hedw.) T.J.Kop. and Polytrichum commune Hedw. on drying to 50% relative water content of the air and rehydration. Changes in the intensity of photosynthesis and respiration as well as the content of malate and citrate in leafy moss stems were analysed. P. commune gametophores showed greater resistance to drought stress than P. undulatum. In both species, photosynthesis was much more sensitive to drought than respiration. Changes in the content of malate and citrate indicated a high plasticity of moss metabolism in conditions of water shortage and may be one of many important elements of the adaptation strategy to water deficit. The reactions of the tested mosses to dehydration and rehydration confirmed their adaptation to specific land conditions.
2
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What do plants do in winter?

88%
EN
Plants can be divided according to susceptibility to cold or frost resistance owing to their tolerance. In the temperate climate, most plants are tolerant of low temperatures and have evolved mechanisms which enable them to survive the winter and limit the negative effects. Gradual temperature drops and the gradual shortening of days in the autumn are extremely important in preparing the plant for the winter. Reduction of cell membrane fluidity and a decrease in efficiency of photosynthesis are the main mechanisms for plant perception of weather conditions. This perception stimulates the induction of processes to acquire tolerance to unfavourable conditions by modulating gene expression, the accumulation of specific proteins with cryo-protective properties and the synthesis of osmotically active and antioxidant compounds. Some species overwinter as dormant, whereas others called evergreens, maintain metabolic activity adjusted to the winter conditions.
PL
Mchy są organizmami dogodnymi do badania reakcji na stres wodny, ponieważ nie posiadają epidermy, przez co odznaczają się większą wrażliwością na zmiany wilgotności niż większość innych roślin. Celem pracy było określenie wpływu stresu wodnego na przebieg procesów fizjologicznych mchów na przykładzie Polytrichum piliferum Hedw. Przeprowadzone badania pokazały, że działanie abiotycznego stresora, jakim jest woda, wpływa niekorzystnie na przebieg procesów fotosyntezy i oddychania, poprzez zmniejszenie ich natężenia. Jednak warto zaznaczyć, że proces oddychania jest w mniejszym stopniu uzależniony od uwodnienia tkanek niż proces fotosyntezy, co wyraźnie widać w przeprowadzonych tu badaniach. Za odporność mszaków na czynniki stresowe odpowiada zdolność rośliny do utrzymania homeostazy w czasie działania stresora. Również ważną rolę odgrywa zdolność zmiany homeostazy przez adaptację, przetrwanie albo pokonanie niekorzystnych warunków życiowych.
EN
Mosses are convenient organisms for studying the reaction to water stress because they do not have an epidermis, which makes them more sensitive to changes in humidity than most other plants. The aim of the study was to determine the effect of water stress on the course of physiological processes of mosses using Polytrichum piliferum Hedw. The present study showed that the action of the abiotic stressor, which is water, adversely affects the photosynthesis and dark respiration processes by reducing their intensity. However, it is worth noting that the respiration process is less dependent on tissue hydration than the photosynthesis, which is clearly demonstrated by the study results. The bryophytes’ resistance to stress factors is responsible for the plant’s ability to maintain homeostasis under stress conditions. The ability to change homeostasis by adapting, surviving or overcoming adverse living conditions also plays an important role.
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Co rośliny robią nocą?

88%
EN
Life on Earth is dependent on several factors. One of them is the light and the reactions taking place with his participation. With the reactions of photosynthesis solar energy is converted into energy of chemical bonds and in this form is transmitted from autotrophic organisms (the producers) to all organisms. The reactions of photosynthesis also produce oxygen, which is necessary for most of the organisms and used in the reactions of cellular respiration. Since plants produce energy and oxygen during the day, whether in this case the night is needed at all. And if so, what are plants doing at night? This paper describes the major physiological and biochemical processes that occur in plants under no access to light, both natural conditions (night) and in the case of artificial darkness. The answer to the question posed in the title is in the description of such processes as photosynthesis, cellular respiration, tropisms, control of the stomata opening/closing and regulation of flowering.
PL
Życie na Ziemi jest zależne od kilku czynników. Jednym z nich jest światło i reakcje zachodzące przy jego udziale. To dzięki reakcjom fotosyntezy energia promieniowania słonecznego zamieniana jest w energię wiązań chemicznych i w tej postaci przekazywana jest od organizmów autotroficznych, czyli producentów do wszystkich orga nizmów. W reakcjach fotosyntezy powstaje również tlen, który jest niezbędny dla większości organizmów i wykorzystywany w reakcjach oddychania komórkowego. Skoro rośliny produkują energię i tlen w dzień, to czy w takim razie noc jest im w ogóle potrzebna. A jeśli nawet tak, to co one robią w nocy? Praca ta opisuje najważniejsze procesy fizjologiczne i biochemiczne zachodzące w organizmach roślinnych przy braku dostępu do światła, zarówno w warunkach naturalnych (noc), jak i w sytuacji sztucznego zaciemnienia roślin. Odpowiedź na pytanie postawione w tytule pracy znajduje się w omówieniu m.in. takich procesów jak: fotosynteza, oddychanie komórkowe, ruchy roślin, regulacja otwierania/zamykania aparatów szparkowych i regulacja kwitnienia.
EN
Picocyanobacterium Synechococcus sp. is very important but still poorly understood component of marine and freshwater ecosystems. In this study, the effect of single and multiple addition of cell-free filtrate obtained from Synechococcus sp. on selected cyanobacteria Synechocystis sp., Geitlerinema amphibium, Nodularia spumigena and Nostoc sp. was investigated. The species present in this work are groups of aquatic phototrophs known to co-occur in the Baltic Sea. The study showed that the picocyanobacterial cell-free filtrate inhibit the growth and changed the cell morphology of filamentous cyanobacteria G. amphibium, N. spumigena and Nostoc sp. It was shown that the addition of cell-free filtrate caused a decline of pigmentation and cell lysis of G. amphibium, N. spumigena and Nostoc sp. compared to the control culture. In addition, it was observed that the filtrate obtained from Synechococcus sp. did not affect the Synechocystis sp. It was found that the filtrate obtained from picocyanobacterium had the strongest effect on growth of G. amphibium, therefore for this cyanobacteria performed additional experiments to showed whether the filtrate affected also photosynthetic pigments, chlorophyll fluorescence and photosynthesis. The study proved that the picocyanobacterial allelopathic compounds reduce the efficiency of photosynthesis, which results in the inhibition of growth of target organisms. This way of interaction may explain the formation of almost monospecific cyanobacterial blooms in many aquatic ecosystems, including in the Baltic Sea.
EN
The aim of this study was to investigate the influence of copper and vanadium ions on photosynthetic activity of carrot (Daucus carota L. subsp. sativus (Hoffm.) Schübl. & G. Martens) and winter wheat (Triticum aestivum L.). Measurements of the total chlorophyll content were performed – the SPAD chlorometer and the basic chlorophyll a fluorescence parameters were determined using the FMS-1 fluorometer – Hansatech. The studies used aqueous solutions of copper salt (CuSO4) and vanadium (H4NO3V), with molar concentrations: 0.6 mM, and 3 mM. The control group consisted of plants watered with distilled water. Both in carrots and in wheat, together with an increase in the concentration of heavy metal ions, a decrease in the content of chlorophyll was observed and significant changes in the activity of the photosystem were demonstrated II. Measurements of chlorophyll fluorescence kinetics and only in D. carota subsp. sativus showed a statistically significant effect of 3 mM solutions of copper and vanadium ions on photosynthetic activity. In T. aestivum none of the heavy metal ions induced significant changes in the values of chlorophyll a fluorescence.
EN
In the whole world, researches are conducting on toxic effect of heavy metals on living organisms. The problem with heavy metal occurrence in the environment is not only associated with their toxicity, but also with their ability to accumulate inside living organisms. This study presents the effect of copper and vanadium ions on germination and growth of carrot (Daucus carota L subsp. sativus (Hoffm.) Schübl. & G. Martens.) and winter wheat (Triticum aestivum L.). The experiment was carried out in two independent series with ten repetitions each. The water solutions of copper (CuSO4) and vanadium (H4NO3V) salts with the concentrations: 0.6 mM, 0.3 mM, 3 mM and 6 mM were used. The control groups were objects watered with distilled water. The conducted experiment showed that, the copper and vanadium ions had negative effect on germination and growth of plants. With the increasing of concentration of heavy metal ions an inhibition of seeds germination capacity was observed. The length of D. carota and T. aestivum seedlings in each salt solutions was inhibited, compared to the control group. During the growth phase, the stimulation of wheat leaves growth, only on copper solutions with concentration 3 mM and 6 mM was observed. Changes of a fresh and dry weight, and a water content were observed, depending on the copper and vanadium ions concentration.
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