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Wyszukujesz frazę "heat-stress" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Non-invasive technique of crop heat-stress resistance estimation
Autorzy:
Trojak, Magdalena
Skowron, Ernest
Powiązania:
https://bibliotekanauki.pl/articles/1179185.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
barley
heat resistance
heat stress
modulated fluorescence (PAM)
photosystem II (PSII)
Opis:
Sessile organisms like plants have drastically reduce possibility to avoid harmful influence of the natural habitat. Evolution of first land plants allowed adapting to harsh conditions, yet despite broad range of tolerance factors such as excessive light and temperature impose limitation for biological activity because viability and in the case of crops the productivity is limited. In fact, physiologists make lots of efforts to increase stress tolerance searching and selecting new cultivars of known crops. As in most cases the exact mechanism of reached improvement is still missing selection is occupied by immense amount of time, energy and funds. Proposed in paper technique of stress resistance estimation is inexpensive and highly reproducible solution for crop selection even at early stage of development. It is based on well-known fluorescent assessment (PAM) of plant photosynthetic machinery expose to factor of interest. We tested two barley (Hordeum vulgare L.) cultivars spring Carina and winter Lomerit exposed to thermal stress and estimated maximal (Fv/Fm) and effective photosystem II quantum yield precisely specifying the way absorbed energy is utilized by photochemical (ΦPSII) or regulated (ΦNPQ) and non-regulated (ΦNO) non-photochemical manner. Studies have confirmed various heat-resistance of tested barley cultivars and proved PAM technique utility.
Źródło:
World Scientific News; 2017, 83; 168-181
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cognitive Function in Tropical Climate
Autorzy:
Robin, Nicolas
Coudevylle, Guillaume
Powiązania:
https://bibliotekanauki.pl/articles/1177787.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Heat stress
cognition
mental performance
task complexity
tropical climate
Opis:
The physiological and psychological responses to environmental heat stress have been well established. However, in the tropical climate (i.e., hot: 31 ±2 °C and wet climatic environment: 75% ± 10% rH), that concerns millions of people, most studies deals with exercise: Aerobic exercise is negatively affected and the impact of this environment on cognition is unclear. This short communication reviews some studies using cognitive tasks realized in tropical climate or using environmental conditions leading heat stress. In agreement with the literature, it is suggested that, at school, office or university in tropical climates, it is preferable to study in air conditioning or naturally ventilated rooms than in hot and wet climatic conditions in order to reduce feelings of fatigue and thermal discomfort. Further investigations, using cooling or psychological training techniques are needed in order to try to limit the negatives effects of tropical climate on cognition.
Źródło:
World Scientific News; 2018, 100; 244-247
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of plant heat tolerance by modification of xanthophyll cycle activity
Autorzy:
Trojak, Magdalena
Skowron, Ernest
Powiązania:
https://bibliotekanauki.pl/articles/1178460.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ascorbic acid (AsA);
calcium ions (Ca2+)
dithiothreitol (DTT)
heat stress
plant protection products (PPPs)
putrescine (Put)
xanthophyll cycle
Opis:
Plants are sessile organisms hence environmental factors such as excessive light and high air temperature lead to significant reductions of their productivity and quality of gained yield. In fact, scientific and agriculture hubs make lots of efforts to improve crop tolerance to elevated temperature, selecting more tolerant varieties. We analyzed less expensive and highly efficient method to improve resistance of well-known cultivars of crop plant by reversible modification of xanthophyll cycle. It functions as a safety valve to adjust energy transfer and protects fragile structures of photosynthetic machinery from excessive light, especially accompanied by heat or water stress. Efficiency of modified xanthophyll cycle activity was measured after pre-treatment with four, chemically different regulators, with or without light illumination. Analyses were carried out on barley (Hordeum vulgare L.) cv. Zenek treated with ascorbic acid (AsA), dithiothreitol (DTT), putrescine (Put) and calcium ions (Ca2+). To measure the scale of thermal energy dissipation we traced energy transfer absorbed by PSII with PAM chlorophyll fluorescence technique. Results showed clear correlation between AsA (activator of violaxanthin de-epoxidase) treatment and stimulation of the Φ(NPQ) at increased temperature. DTT (inhibitor of violaxanthin de-epoxidase) decreased the cycle activity at 45 °C at the same time increasing its value at 35°C, caused by interaction with other enzymes. Action of Put (hydrogen ions buffer) concerned mainly a non regulated Φ(NO) energy quenching. We noticed that application of Ca(NO3)2 (Ca2+ source for enzyme activity) reduced the Φ(NPQ) at 45 °C and stimulated it at 25 °C. Obtained results confirmed postulated possibility of creating new type of plant protection products (PPPs) able to precisely manage natural mechanisms of heat resistance.
Źródło:
World Scientific News; 2017, 70, 2; 51-70
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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