The ameliorative role of 28-homobrassinolide under chilling stress in various growth, photosynthesis, enzymes and biochemical parameters of cucumber (Cucumis sativus L.) were investigated. Cucumber seedlings were sprayed with 0 (control), 10-8, or 10-6 M of 28-homobrassinolide at the 30-day stage. 48 h after treatment plants were exposed for 18 h to chilling temperature (10/8°C, 5/3°C). The most evident effect of chilling stress was the marked reduction in plant growth, chlorophyll (Chl) content, and net photosynthetic rate, efficiency of photosystem II and activities of nitrate reductase and carbonic anhydrase. Moreover, the activities of antioxidant enzymes; catalase (E.C. 1.11.1.6), peroxidase (E.C.1.11.1.7), superoxide dismutase (E.C. 1.15.1.1) along with the proline content in leaves of the cucumber seedlings increased in proportion to chilling temperature. The stressed seedlings of cucumber pretreated with 28-homobrassinolide maintained a higher value of antioxidant enzymes and proline content over the control suggesting the protective mechanism against the ill-effect caused by chilling stress might be operative through an improved antioxidant system. Furthermore, the protective role of
28-homobrassinolide was reflected in improved growth, water relations, photosynthesis and maximum quantum yield of photosystem II both in the presence and absence of chilling stress. and Q. Fariduddin ... [et al.].
Odlupováním vrstevnatých materiálů (např. grafitu) lze připravit 2D krystaly s tloušťkou jednoho nebo několika málo atomů. Nejznámějším takovým 2D materiálem je grafen (monovrstva grafitu), nicméně v současnosti existují a intenzivně se zkoumají desítky podobných struktur. Příspěvek podává základní přehled o 2D materiálech, jejich vlastnostech, metodách přípravy a možných aplikacích., Layered materials (such as graphite) can be exfoliated to produce 2D crystals with a thickness of one of just a few atoms. The best known 2D material is graphene (monolayer of graphite), yet there are tens of similar structures, which are being studied intensively at the moment. This article presents a brief summary of 2D materials, their properties, methods of preparation and potential application., Zdeňka Hájková, Martin Ledinský, Matěj Hývl, Aliaksei Vetushka, Antonín Fejfar, Jaroslava Řáhová, Otakar Frank., and Obsahuje bibliografické odkazy