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Start Over Rights http://creativecommons.org/licenses/by-nc-sa/4.0/ Data provider Academy of Sciences Library/Knihovna Akademie věd ČR

1975. Ambient levels of UV-B in Hawaii combined with nutrient deficiency decrease photosynthesis in near-isogenic maize lines varying in leaf flavonoids: Flavonoids decrease photoinhibition in plants exposed to UV-B

Creator:
Lau, T. S. L., Eno, E., Goldstein, G., Smith, C., and Christopher, D. A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
anthocyanins, chlorophyll fluorescence, CO-assimilation, stomatal conductance, and Zea
Language:
Multiple languages
Description:
Near-isogenic lines of maize varying in their genes for flavonoid biosynthesis were utilized to examine the effects of foliar flavonoids and nutrient deficiency on maximum net photosynthetic rate (PN) and chlorophyll (Chl) fluorescence (Fv/Fm) in response to ultraviolet-B (UV-B) radiation. Plants with deficient (30 to 70 % lower N, K, Mn, Fe, and Zn) and sufficient nutrients were exposed to four irradiation regimes: (1) no UV-B with solar photosynthetically active radiation (PAR), (2) two day shift to ambient artificial UV-B, 8.2-9.5 kJ m-2 d-1 (21-25 mmol m-2 d-1); (3) continuous ambient artificial UV-B; (4) continuous solar UV-B in Hawaii 12-18 kJ m-2 d-1 (32-47 mmol m-2 d-1). The natural ratio of UVB: PAR (0.25-0.40) was maintained in the UV-B treatments. In the adequately fertilized plants, lines b and lc had higher contents of flavonoids and anthocyanins than did lines hi27 and dta. UV-B induced the accumulation of foliar flavonoids in lines hi27 and b, but not in the low flavonoid line dta or in the high flavonoid line lc. In plants grown on deficient relative to adequate nutrients, flavonoid and anthocyanin contents decreased by 30-40 and 40-50 %, respectively, and Chl a and Chl b contents decreased by 30 and 70 %, respectively. The UV-B treatments did not significantly affect PN and Fv/Fm in plants grown on sufficient nutrients, except in the low flavonoid lines dta and hi27 in which PN and Fv/Fm decreased by ∼15 %. PN, Fv/Fm, and stomatal conductance decreased markedly (20-30 %) in all lines exposed to UV-B when grown on low nutrients. The decrease in Fv/Fm was 10 % less in higher flavonoid lines b and lc. The photosynthetic apparatus of maize readily tolerated ambient UV-B in the tropics when plants were adequately fertilized. In contrast, ambient UV-B combined with nutrient deficiency significantly reduced photosynthesis in this C4 plant. Nutrient deficiency increased the susceptibility of maize to UV-B-induced photoinhibition in part by decreasing the contents of photoprotective compounds. and T. S. L. Lau ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1976. Améboidní invazivita nádorových buněk

Creator:
Brábek, Jan and Rösel, Daniel
Type:
article and TEXT
Language:
Czech
Description:
Invazivita nádorových buněk je kritickým krokem tvorby metastází. V současné době jsou známy dva hlavní způsoby buněčné invazivity. Mezenchymální invazivita závislá na degradaci mezibuněčné hmoty a nově popsaná améboidní invazivita charakterizovaná zvýšenou aktivitou Rho-kinázy. Článek diskutuje současné názory na mechanismy améboidní invazivity. and Invasivity of malignant tumour cells is a critical stage in the onset of metastases. At present two main types of invasion process in cells are known: mesenchymal invasivity based on degradation of intercellular substances and a newly described ameboid invasivity characterized by enhanced activity of the enzyme Rho-kinase. Various opinions on the mechanism of ameboid invasivity are discussed.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

1977. Ameliorating effects of three kinds of antioxidants to ozone-polluted painted nettle (Coleus blumei Benth.)

Creator:
Zhang, L., Jia, L. L., Sui, J. X., Wen, M. X., and Chen, Y. J.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fluorescence chlorofylu a, výměna plynu, kinetin, Na-askorbát, spermidin, chlorophyll a fluorescence, gas exchange, Na-ascorbate, spermidine, 2, and 581
Language:
Multiple languages
Description:
Ground concentration of ozone (O3) causes serious threat to plants. In order to protect sensitive plants from O3 pollution, many kinds of antioxidants were assessed in previous studies. In this study, effects of O3 fumigation (a single spike of 120 ± 20 nmol mol-1 for four hours) on an ornamental species (Coleus blumei) was examined in open-top chambers. Before the O3 treatment, plants were sprayed respectively either with a solution of three different antioxidants [Na-ascorbate (NaAsA), kinetin (KIN), and spermidine (Spd)] or with distilled water to compare their protective effects to plants. Our results revealed that O3 fumigation impaired the plasma membrane, decreased chlorophyll (Chl) content, inhibited photosynthesis, induced photoinhibition and photodamage, and caused visible injury. Spraying with KIN, NaAsA or Spd ameliorated the decrease of the Chl content and photosynthetic capability, the impairment of membrane, and visible injury under O3 fumigation. The plants treated with KIN showed the best ability to mitigate the injury caused by O3., L. Zhang, L. L. Jia, J. X. Sui, M. X. Wen, Y. J. Chen., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1978. Ameliorative role of salicylic acid and spermidine in the presence of excess salt in Lycopersicon esculentum

Creator:
Fariduddin, Q., Khan, T. A., Yusuf, M., Aafaqee, S. T., and Khalil, R. R. A. E.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
abiotické faktory, antioxidanty, fotosyntéza, abiotic factors, antioxidants, photosynthesis, prolin, kyselina salicylová, spermidin, rajče jedlé, proline, salicylic acid, spermidine, Lycopersicon esculentum, 2, and 581
Language:
Multiple languages
Description:
Salicylic acid (SA) and polyamines (PA) are widely used to overcome various abiotic stresses including salt (NaCl) stress in plants. In the present investigation, co-application efficacies of SA and PA on the salt stress (200 mM NaCl) were evaluated in Lycopersicon esculentum. After transplantation, at 10-d stage, seedlings were exposed to NaCl through soil and then allowed to grow till 30-d stage. At 31-d stage of growth, plants were sprayed with double distilled water (control) or spermidine (1.0 mM) and/or SA (10-5 M). The salt stress significantly reduced the growth, gas-exchange parameters, but increased antioxidant enzymes and proline content in the leaves. Moreover, the loss caused by salt stress was successfully restored by the following treatment of spermidine and SA., Q. Fariduddin, T. A. Khan, M. Yusuf, S. T. Aafaqee, R. R. A. E. Khalil., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1979. American mink, Mustela vison diet and predation on waterfowl in she Słońsk Reserve, western Poland

Creator:
Bartoszewicz, Magdalena and Zalewski, Andrzej
Type:
article and TEXT
Subject:
American mink, diet, predation on birds, waterfowl nesting success, and predator impact
Language:
English
Description:
The abundance, diet, and prey relationships of American mink Mustela vison were studied in the Słońsk Reserve (W Poland) on two plots: shore and reservoir. Estimated mink number within the Reserve was 69 in autumn–winter 1998/1999 and 50 during spring 1999. The diet of American mink consisted mainly of mammals, birds and fish. In autumn–winter, birds formed 4–16%, whereas mammals constituted up to 56% and fish up to 62% of the biomass consumed, depending on the plot. In spring and summer, however, birds formed 45–60% of the biomass consumed in the reservoir and 35–46% of the biomass taken by mink on the shore. The European coot Fulica atra was the most frequently consumed prey. In spring, mink removed 7.8% (N=278 killed birds) of coots nesting in the Reserve, 1.8% (N=9) of breeding grebes Podiceps spp. and 11.2% of ducks (N=93 taken birds). On straw platforms only 13.6% of greylag geese Anser anser broods were successful. From 35 to 77% of the nests on straw platforms were destroyed by mink. In wooden boxes 46.4% of mallard Anas platyrhynchos and 33.3% of shelduck Tadorna tadorna nests were successful. American mink destroyed 22–40% of the nests in boxes. However, the arrival of American mink to the Słońsk Reserve has not resulted in a noteworthy decrease in waterfowl populations.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/

1980. American policy, Korean War, and the lessons of Munich

Creator:
Mareš, Petr and Mareš, Jiří
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
historic, Munich agreement, German Sudetenland, Nazi Germany, and Cold War
Language:
English
Description:
In this article, the author traces how the lessons of the Munich Agreement of September 1938 (on the basis of which Czechoslovakia was forced to cede the predominantly ethnic-German Sudetenland to Nazi Germany) were projected into US foreign policy. In Part One of the essay, based on published sources and unpublished documents from American archives, the topic is covered from the late 1930s to the outbreak of the Korean War (which is discussed in Part Two, to be published in the next issue of Soudobé dějiny). The author looks at immediate American reaction to the North Korean attack on South Korea in June 1950, and then returns to autumn 1938 to test his hypothesis that behind the unusual unity of this reaction was the ingrained negative attitude of the United States to the policy of appeasement. He demonstrates that since the late 1930s the terms ‘Munich’ and ‘appeasement’ have remained forever linked in US policy and US public discourse, and he discusses the transformations of the perception of the two concepts during the Second World War, after the war, and at the beginning of the Cold War. The lessons of Munich, he argues, have drawn on the idealistic as well as the pragmatic sources of US policy, because they stem from the conviction that appeasement is immoral and does not pay. Whereas in Roosevelt’s policy the general lesson was not to allow Hitler’s expansion, Harry S. Truman, Roosevelt’s successor in the White House, had to use the lessons, despite his own self-restraint, to try to counter the steps of a wartime ally, Stalin’s Soviet Union. The Communist take-over in Czechoslovakia in February 1948 and the blockade of the western sectors of Berlin beginning in the summer of that year were important events on this path.The author further considers the infl uence of this factor on the US approach taken in the Korean War in the early 1950s. He seeks to demonstrate that the decision of the Truman Administration to substantially intervene in this confl ict was a direct consequence of the negative attitude to the policy of appeasing an aggressor. This attitude was also shared by the American public, regardless of party affi liation and political sympathies. Arguments based on the rejection of appeasement, however, soon began to be used by the Republicans as ammunition in the election campaign against the incumbent Democrats and the choice of strategy also became a matter of dispute in the choice of strategy on the Korean battlefi eld after China entered the war. Whereas the White House wished to avoid an unlimited confl ict with China, the Commander-in-Chief of the United Nation Command in Korea, General Douglas MacArthur (1880–1964), was in favour of an uncompromising approach and in fact ceased to obey President Harry S. Truman (1884-1972). After being relieved of his command by Truman, MacArthur became the chief critic of his policies and a hero of Truman’s Republican opponents. In spring 1951, the Republicans organized a special Senate committee hearing on the circumstances of MacArthur’s suspension. The author looks in detail at this exceptional clash in post-war US domestic politics, which was meant to be triumphantly used against MacArthur, but gradually changed into a debacle in consequence of, among other things, the compelling testimonies of Secretary of State Dean Acheson (1893-1971) and Secretary of Defense George C. Marshall (1880-1959). In his conclusion, the author seeks to demonstrate how other US presidents returned to the ‘lessons of Munich’, and he argues that these lessons became Truman’s lasting political legacy and as such became fi rmly rooted in American political discourse. and Přeložil: Jiří Mareš
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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