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Effect of elevated CO2 on morphological and photosynthetic parameters in two understory grass species in Beskydy Mountains
Holub, Petr ; Klem, Karel ; Urban, Otmar
We transplanted two grass species, Calamagrostis arundinacea and Luzula sylvatica, to the understory of\na 10-year-old experimental mixed forest exposed to ambient (385 μmol CO2 mol–1, AC) and elevated (700\nμmol CO2 mol–1, EC) atmospheric CO2 concentration using a glass dome facility. Effects of EC on plant\nmorphology and photosynthesis were examined after three years of treatment. We tested the hypotheses\nthat shade-tolerant species can profit from EC even at low light conditions and that relatively low accumulation\nof assimilates at such light conditions will not cause CO2-induced down-regulation of photosynthesis.\nWe expected that EC can substitute insufficient light intensities under the tree canopy and lead to both\nhigher biomass production and survival of plants in deep forest understories. The typical shade-tolerant\nspecies L. sylvatica exhibited positive acclimation under EC allowing higher light use efficiency under subsaturating\nlight intensities as compared to plants grown under AC. In contrast, C. arundinacea showed\nhigher stimulation of growth and photosynthetic rates by EC mainly under saturating light intensities at\nthe beginning of the growing season, when the forest leaf area is not fully developed and the open canopy\nallows a greater proportion of incident light to reach the understory. Our data indicate that growth and\nphysiological responses of EC plants in forest understories are species specific, differ from responses of\nsun-exposed plants, and depend on degree of shading.
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Interactive effect of UV radiation and CO2 treatment on extractable volatile organic compounds from European beech leaves
Večeřová, Kristýna ; Pernicová, N. ; Klem, Karel ; Urban, Otmar
The main objective of this experiment was to investigate the combined effect of different UV treatments\nand elevated CO2 concentration on monoterpene and methyl salicylate (MES) content in leaves of\nEuropean beech during the growing season. Plants were grown under ambient (AC, 400 μmol mol–1) and\nelevated (EC, 700 μmol mol–1) CO2 concentrations and three UV radiation treatments (ambient – UVamb,\nexcluded – UV-, and enhanced – UV+). Leaves collected from July to September were extracted in cold\nheptane to determine volatile organic compounds content using gas chromatography. Our results show\nthat AC plants had higher total content of extractable monoterpenes and MES than did EC plants over\nthe whole growing season and irrespective of UV treatment. Limonene, 2-bornene, and ester MES were\nthe most abundant volatile compounds in beech leaves. The highest contents of 2-bornene and MES were\nfound under the UV- treatment and AC. Contents of α-pinene, β-pinene, and carene decreased during the\ngrowing season while the content of limonene increased.
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Comparison of leaf area index dynamics and radiation use efficiency of C3 crops in the Czech Republic
Tripathi, Abishek ; Pohanková, Eva ; Trnka, Miroslav ; Klem, Karel
Leaf area index (LAI) and radiation use efficiency (RUE) are key parameters for plant growth and productivity.\nBecause of irregularities in weather conditions, accurate estimation of crop production requires\nunderstanding relationships between weather, LAI, RUE, and final production. It is thus important to\nstudy how the LAI dynamics, leaf area duration (LAD), and RUE are related to aboveground biomass production\nfor different crops. In our study, we compared aboveground dry mass production, LAI dynamics,\nRUE, and LAD in three C3 crops (spring barley [SB], winter wheat [WW], and oilseed rape [OSR]) in the\nCzech Republic. LAI was measured on the basis of transmitted photosynthetically active radiation, LAD\nwas calculated by counting the number of days in the growing season, RUE was measured using Beer’s\nlaw, and the aboveground dry mass was estimated at the time of harvest. Results of our study showed high\nbiomass production and RUE in SB while there was highest maximum LAI (LAImax) and LAD in OSR. We\nconcluded that LAI dynamics or LAImax do not fully reflect the crop production and that RUE may be considered\nas a better indicator for aboveground dry mass production.
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Water-use efficiency of winter wheat under heat and drought stress
Hlaváčová, Marcela ; Klem, Karel ; Novotná, Kateřina ; Rapantová, Barbora ; Urban, Otmar ; Hlavinka, Petr ; Smutná, P. ; Horáková, V. ; Škarpa, P. ; Trnka, Miroslav
Because such extreme weather events as dry spells and heat waves are expected to occur more frequently\ndue to climate change, the issue of appropriate water management for sustainable agricultural production\nis increasingly important. This study focuses on wheat, the second most widely grown cereal in the world\nand the most common cereal in European countries. The study assesses the effects of short periods (3 and\n7 days) of high temperatures (26°C as a control, 32°C, 35°C, and 38°C as daily temperature maxima from\n12:00 to 14:00) and drought stress at different developmental stages (DC 31 – beginning of stem elongation,\nDC 61 – flowering, and DC 75 – early grain filling) on water-use efficiency (WUE) in winter wheat\ncultivar Tobak. This cultivar is one of the most widespread winter wheat cultivars in Czech Republic fields.\nThe analysis of WUE showed that the cv. Tobak plants were able to withstand drought stress conditions\nthrough increased WUE. In contrast, wheat plants were stressed more markedly if exposed to higher temperatures\nand drought in combination. Generally, the wheat plants were most sensitive to drought at DC\n31.
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Effect of nutrients deficiencies on root architecture and growth of winter wheat
Rattanapichai, W. ; Klem, Karel
The study of the effects of N, P, K deficiencies on root architecture and growth was tested in phenotyping platform with winter wheat (Bohemia variety). The experiment was arranged with 4 treatments: Complete nutrient, Without N, Without P and Without K. The root were grown on the surface of vertically fixed black filter paper sheets (30x60cm), covered from both sides by black plastic sheets (PVC-P). The system was setup with a micro-irrigation channel in the top of sheets to ensure circulation of hydroponic medium as hydroponic system. Eighteen days after transplanting, we took the root images by the standard RGB digital camera. To evaluate the root architecture parameters the "SmartRoot" software was used. The results showed that nutrient deficiency had effect on root architecture of winter wheat. N deficiency increase in total seminal root and lateral root length and root/shoot ratio, while P deficiency resulted in increase of mean root diameter, total root area when compared to the control. N deficiency also decreased root and shoot dry weight and total leaf area. However, nutrient deficiency slightly decreased lateral density. There was a slight effect of K deficiency on root architecture when compared to the complete nutrient application. The increasing of leaf dry weight was related with the increased of root dry weight.
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Effect of temeperature stress and water shortage on thousand grain weight of selected winter wheat varietes
Hlaváčová, Marcela ; Pohanková, Eva ; Klem, Karel ; Trnka, Miroslav
The aim of the presented study was to assess the effect of high temperatures and water shortage during anthesis on thousand grain weight (TGW) of two winter wheat varieties (Tobak and Pannonia). In addition, numbers of grains per spike were also assessed. The six growth chambers were used to simulate heat stress conditions within following gradient of temperature maxima: 26 degrees C (control chamber), 29, 32, 35, 38 and 41 degrees C. The relative humidity (RH) course and photosynthetically active radiation (PAR) intensity were controlled via protocols. Additionally, drought stressed (dry) and well-watered (wet) treatments were established within each growth chamber. The plants were removed from the growth chambers after 14 days and they were left until a full maturity, exposed to actual weather conditions. The TGW at 14% moisture were evaluated for particular treatments within both winter wheat varieties. TGW was generally more affected by high temperatures under drought stress than in well-watered conditions. The results revealed that Pannonia TGW was much more affected by the water deficiency in combination with high temperature (particularly 38 and 41 degrees C) than Tobak TGW.
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Effect of high temperature and water shortage stresses duration during anthesis on the selected winter wheat yield formation components
Hlaváčová, Marcela ; Rapantová, Barbora ; Surá, Kateřina ; Klem, Karel ; Hlavinka, Petr ; Trnka, Miroslav
The aim of this study was to assess the effect of drought and high temperatures on Tobak winter wheat variety during one of the most sensitive developmental stage (anthesis) from the viewpoint of harvest index (HI) and spike productivity (SP). The 5 growth chambers (where the plants were exposed to these stress factors) were used for these purposes. The various protocols consisting in photosynthetically active radiation (PAR) course, relative air humidity (RH) and daily temperature courses were run. The plants were divided into 2 groups within each growth chambers: (1) Drough-stressed (Dry) and (2) well-watered (Wet). Two lengths of stresses duration were tested: 3 and 7 days. The plants were exposed to ambient weather conditions up to the full maturity after stresses exposition within the growth chambers. Subsequently, the plants were harvested manually and HI and SP were evaluated. The statistical analyses showed that the effect of each stress factor separately was statistically significant both for HI and SP14, nevertheless, these two factors interaction was statistically significant only in the case of HI.
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Effect of drought stress on selected winter wheat yield formation components within pot and field experiimental design
Hlaváčová, Marcela ; Pohanková, Eva ; Klem, Karel ; Hlavinka, Petr ; Trnka, Miroslav
The object of this study was to find out what is the behaviour of the same winter wheat variety (Bohemia) plants cultivated within pot and field experiment. Therefore, the main aim of this study was to verify (based on the pot experiment results) whether the pot experiment (that is limited by the soil area) does not substantially affect plant reactions. The pot experiment was carried out in growth chambers where daily temperature course, relative humidity (RH) and photosynthetically active radiation (PAR) were set via protocols. The pots were exposed to the drought stress for 14 days with the daily maximum temperature 26 °C from noon to 2 p.m. The pots were split into 2 groups: (1) Dry where the soil moisture within pots were maintained below 30% of the maximum water holding capacity, (2) Wet where the soil moisture did not decrease below 70% of the maximum water holding capacity. The plants within Wet variant were considered as a control group. The pots were placed onto the concrete floor of a vegetation hall (where the plants were exposed to the weather conditions) prior and after stress regime exposition. The field experiment was conducted within experimental station in Bystřice nad Pernštejnem belonging to the Bohemian-Moravian Highlands in the Czech Republic. The drought stress was established through the transparent roofs installed above plants’ tops level in the field. The control experimental plot without roofs was nearby there as well. The plants were harvested when the full maturity was reached and the selected yield formation components were evaluated.
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Vliv vysokých teplot a různých vodních režimů na tvorbu nadzemní biomasy vybraných odrůd pšenice ozimé
Hlaváčová, M. ; Klem, Karel ; Hlavinka, Petr ; Trnka, Miroslav
Cílem této studie bylo hodnocení vlivu vysoké teploty a nedostatku půdní vláhy v období kvetení na alokaci nadzemní biomasy dvou odrůd pšenice ozimé (Bohemia a Pannonia). Za tímto účelem byly simulovány podmínky stresu teplem s těmito teplotními maximy: 26 °C (kontrolní komora), 29, 32, 35, 38 a 41 °C. Průběh relativní vlhkosti vzduchu (RV) a fotosynteticky aktivní radiace (FAR) byl řízen prostřednictvím protokolů. Kromě toho byla v každé komoře ustanovena varianta stresovaná suchem (Dry) a varianta optimálně zalévaná (Wet). Rostliny byly po 14 dnech stresového režimu vyjmuty z komor a do období plné zralosti byly vystaveny vlivům aktuálního počasí. Po sklizni byla pro všechny varianty nastolených stresových podmínek obou odrůd vyhodnocena produktivita hlavních klasů a sklizňový index (HI) hlavních klasů
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