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Effect of elevated CO2 concentration and nitrogen nutrition on mais response to short-term high temperature and drought stress
Simor, J. ; Klem, Karel
Within an experiment conducted in open top chambers in which two mais genotypes differing in stay-green trait were cultivated under elevated atmospheric CO2 concentration (EC) in comparison\nwith ambient CO2 concentration (AC), and in two contrast levels of nitrogen nutrition, the effect of acclimation to these factors on photosynthetic performance and water use efficiency, and subsequent response to short-term high temperature and drought stress was studied. Although EC improved water use efficiency, this effect did not alleviate the response to drought stress, and under some combinations of factors even led to a decrease in CO2 assimilation rate under drought stress. Differences in the stay- green trait between genotypes did not have a major effect on the response to high temperature and drought stress. Differences between genotypes were manifested mainly in the interaction with nitrogen nutrition, while in the Korynt genotype, non fertilised variants showed a lower response of CO2 assimilation rate to drought. Slight alleviating effect of higher nitrogen dose was found under EC conditions, while no nitrogen fertilisation rather increased drought resilience under AC conditions.
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Interactive effects of adaptation technology, based on no-till sowing into the mulch of cover crop residues, and nitrogen nutrition on photosynthetic performance of maize under drought stress
Opoku, Emmanuel ; Holub, Petr ; Findurová, Hana ; Veselá, Barbora ; Klem, Karel
The aim of this study was to evaluate the interactive effect of adaptation technology based on no-till sowing into cover crop mulch and nitrogen nutrition on photosynthetic performance of maize under short term drought stress induced by rain-out shelters. The experiment was established in two locations in the same climatic condition but differing in soil fertility. The negative effect of drought on CO2 assimilation rate was modulated by nitrogen nutrition. However, while nitrogen nutrition led to alleviating effect at the location with higher fertility, the opposite effect was found at the site with lower fertility. Adaptation technology had only a minor impact on photosynthetic response to drought, but it generally increased CO2 assimilation rate at the site with higher soil fertility and decreased at the site with lower soil fertility. We can conclude that adaptation technology, despite of assumptions, did not significantly change the resilience of maize to drought, and probably longer use of such technology is required to improve soil water retention and thus also balanced supply of water to plants. \nAt the same time, we did not find a negative impact of adaptation technology on photosynthesis which can be related to cooler soil during maize emergence and slower mineralization, although the use of adaptation technology seems to be more effective in soils with higher fertility.
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Interactive effects of elevated CO2 concentration, nitrogen nutrition and UV-exclusion on yield, aboveground biomass and root development in winter wheat and spring barley
Rattanapichai, W. ; Klem, Karel
Within the manipulation experiment in open top chambers (Domaninek near Bystrice nad Pernstejnem) that allow simulation of elevated concentration of CO2 ([CO2]) (expected by the end of this century700 mu mol mol(-1)) and exclusion of solar UV radiation, the interactive effects of these environmental drivers together with nitrogen application were studied. Aboveground biomass at the time of harvest, grain yield and root area were studied in winter wheat (variety Bohemia) and spring barley (variety Bojos). From three replications of each treatment were the roots of four plants dug out from the soil and gently washed. Photos of roots taken using the digital camera were analysed by image processing software Image J (plugin SmartRoot). The result showed that the elevation of [CO2] increased the above ground biomass and grain yield. High level of nitrogen increased the stimulatory effect of [CO2] on the above-ground biomass and grain yield. Also UV exclusion stimulated the effect of the evaluated [CO2] on above-ground biomass and grain yield. UV exclusion resulted in higher root area than the treatment of non-exclusion of UV.
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Interactive effects of elevated CO2 concentration, drought, and nitrogen nutrition on yield and grain quality of spring barley and winter wheat
Surá, Kateřina ; Rajsnerová, Petra ; Veselá, Barbora ; Klem, Karel
The interactive effects of elevated CO2 concentration (EC; 700 μmol mol–1), drought stress, UV exclusion, and nitrogen nutrition were studied in open-top chambers located in the Bohemian–Moravian highlands (24 in total). Above-ground biomass at the time of harvest, grain yield, and grain quality parameters were studied in winter wheat (variety Bohemia) and spring barley (variety Bojos). The results showed that elevation of CO2 concentrations increased above-ground biomass and grain yield. Higher levels of nitrogen increased the stimulatory effect of EC on above-ground biomass and grain yield. In addition, UV exclusion stimulated the effect of EC. EC generally led to increased rates of photosynthesis and assimilate formation. Increased storage of starch in the grain led to an unbalanced proportion of proteins and a decrease in their relative content in grain. Similarly to grain yield and above-ground biomass, the decrease in protein content under EC was also more pronounced under UV exclusion. EC led also to reduction of other quality parameters, such as the Zeleny sedimentation test. This effect is more pronounced when nitrogen is not a limiting factor as well as under the effect of drought. The stronger effect under drought stress is probably due to increased water use efficiency.
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Odpověď fotosyntetického aparátu smrku ztepilého a buku lesního na vybrané stresové podmínky - srovnávací studie.
NOVÁKOVÁ, Hana
Vzhledem k očekávaným klimatickým změnám je stále důležitější studovat reakci druhů současných ekosystémů na tyto změny. Tato práce je proto zaměřená na reakce dvou hlavních středoevropských druhů lesních stromů ? smrku ztepilého (Picea abies L.) a buku lesního (Fagus sylvatica L.) ? na stres ze sucha, zvýšené množství N v půdě, kombinaci těchto stres-faktorů a na stres horkem. Ú činky stresu byly sledovány na maximální fotochemické efektivitě PS II (Fv / Fm) a na obsahu fotosyntetických pigmentů. Bylo zjištěno, že smrk ztepilý je odolnější než buk lesní vůči všem zmíněným stres-faktorům.
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Vliv hnojení systémem CULTAN na obsah sterolů v nadzemní biomase kukuřice
Pavlík, Milan ; Pavlíková, D. ; Balík, J. ; Najmanová, J.
Výsledky analýz volného β-sitosterolu ukazují jeho rostoucí koncentraci po injektování roztoku hnojiva DAM390 v porovnání s hnojivem dusičnanem ammonným. Koncentrace volného β-sitosterolu v rostlinách rostoucí na variantě ošetřené hnojivem DAM byly zvýšeny více než o 100% během 13 dní po aplikaci hnojiva. Naše výsledky potvrdily vliv podmínek prostředí na změny v obsahu a složení sterolů a úlohu sterolů při regulaci membrán v důsledku měnících se podmínek růstu rostlin.
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