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7632. ECONOS 2006
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7633. ECONOS’06 a prof. Wolfgang Kiefer na Slovensku
- Creator:
- Bugár, Ignác and Uherek, František
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7634. Ecophysiological characteristics of two carrot (Daucus carota L.) cultivars in response to agroecological factors and nitrogen application
- Creator:
- Thiagarajan, A., Lada, R., and Adams, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, Daucas carota, foliar nitrogen, photosynthesis, processing carrots, water-use efficiency, 2, and 58
- Language:
- Multiple languages
- Description:
- Plant density, planting time, harvest timing, and nitrogen influence on short-term gas-exchange properties of carrot cultivars, Topcut and Sugarsnax (Daucus carota L.) were investigated under field conditions. Net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) differed significantly with the cultivars studied. Both planting and harvest timing changed the midday PN rates. P N increased as harvest timing advanced regardless of planting time. Late planting combined with late harvesting registered the maximum P N rates (4.5 μmol m-2 s-1). The water-use efficiency (WUE) was altered by temperature at different harvest timings along with the choice of cultivar. Early harvested Sugarsnax had a higher WUE (2.29 mmol mol-1) than TopCut (1.64 mmol mol-1) as Sugarsnax exhibited more stomatal conductance than TopCut. These changes were principally governed by fluctuations observed with air temperature and photosynthetic photon flux density (PPFD) and altered by the sensitivity of the cultivars to ecological factors. Plant density did not affect the photosynthetic gas-exchange parameters. Our results suggest that carrots manage high population density solely through morphological adaptations with no photosynthetic adjustments. Carrot leaves responded to N application in a curvilinear fashion in both cultivars. N did not alter gs, E, or WUE in carrots. N, applied at a rate of 150 kg N ha-1, increased foliar N up to 2.98%. We conclude that 2.98% of foliar N is sufficient to achieve the maximum photosynthetic rates in processing carrots., A. Thiagarajan, R. Lada, A. Adams., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7635. Ecophysiological response in leaves of Caragana microphylla to different soil phosphorus levels
- Creator:
- Zhao, T. T., Zhao, N. X., and Gao, Y. B.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, adaptive strategy, leaf functional traits, leaf phosphorus allocation, soil phosphorus level, 2, and 58
- Language:
- Multiple languages
- Description:
- Phosphorus (P) is one of the limiting mineral nutrient elements in the typical steppe of Inner Mongolia, China. In order to find out the adaptive strategy of Caragana microphylla to low soil P status, we grew plants in P-deficient soil in April 2009 and gave a gradient of P addition ranging from 0 to 60 mg(P) kg-1(soil) from May 2010. Leaf traits were measured in September 2010. Both leaf growth and light-saturated photosynthetic rate (P max) were similar among different groups. Leaf nitrogen (N):P ratio indicated that the growth of C. microphylla was not P-limited in most of the Inner Mongolia typical steppe, which had an average soil available P content equal to 3.61 mg kg-1. The optimal P addition was 20 mg(P) kg-1(soil) for two-year-old plants of C. microphylla. Leaf mass area (LMA) and leaf dry matter content (LDMC) were enhanced with low P, and significantly negatively correlated with photosynthetic N-use efficiency (PNUE). Photosynthetic P-use efficiency (PPUE) increased with decreasing soil P and increasing leaf inorganic P (Pi): organic P (Po) ratio, and showed no significant negative correlation with LMA or LDMC. P max of C. microphylla did not decline so sharply as it was anticipated. The reason for this phenomenon might be due to the increased PPUE through regulating the leaf total P allocation. C. microphylla had high P-use efficiency via both high PPUE and long P-retention time at low-P supply. The adaptation of C. microphylla to low-P supply provided a new explanation for the increased distribution of the species in the degraded natural grassland in Inner Mongolia, China., T. T. Zhao, N. X. Zhao, Y. B. Gao., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7636. Ecophysiological responses of Caragana korshinskii Kom. under extreme drought stress: leaf abscission and stem survives
- Creator:
- Xu, D. H., Fang, X. W., Su, P. X., and Wang, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chlorophyll content, chlorophyll fluorescence, fluorescence quenching, photosynthesis, stress response, 2, and 58
- Language:
- Multiple languages
- Description:
- Caragana korshinskii Kom. is a perennial xerophytic shrub, well known for its ability to resist drought. In order to study ecophysiological responses of C. korshinskii under extreme drought stress and subsequent rehydration, diurnal patterns of gas exchange and chlorophyll (Chl) fluorescence parameters of photosystem II as well as Chl content were analyzed. Plant responses to extreme drought included (1) leaf abscission and using stem for photosynthesis, (2) improved instantaneous water-use efficiency, (3) decreased photosynthetic rate and partly closed stomata owing to leaf abscission and low water status, (4) decreased maximum photochemical efficiency of photosystem II (PSII) (variable to maximum fluorescence ratio, Fv/Fm), quantum efficiency of noncyclic electron transport of PSII, and Chl a and Chl b. Four days after rehydration, new leaves budded from stems. In the rewatered plants, the chloroplast function was restored, the gas exchange and Chl fluorescence returned to a similar level as control plant. The above result indicated that maintaining an active stem system after leaf abscission during extreme drought stress may be the foundation which engenders these mechanisms rapid regrowth for C. korshinskii in arid environment., D. H. Xu ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7637. Ecophysiological responses of Cunninghamia lanceolata to nongrowing-season warming, nitrogen deposition, and their combination
- Creator:
- Yu, L., Dong, T. F., Lu, Y. B., Song, M. Y., and Duan, B. L.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fruktóza, škrob, chlorofyl, fructose, starch, chlorophyll, fluorescence chlorofylu, výměna plynu, malondialdehyde, reaktivní formy kyslíku, chlorophyll fluorescence, gas exchange, reactive oxygen species, maximal quantum yield of PSII photochemistry, 2, and 581
- Language:
- Multiple languages
- Description:
- Warming winter and atmospheric nitrogen (N) deposition are expected to have effects on net primary production (NPP) of Chinese fir (Cunninghamia lanceolata) plantation and implications for plantation carbon sequestration. The effects of nongrowing-season warming on plant morphological and physiological traits were investigated in a greenhouse experiment with two-year-old C. lanceolata seedlings. Elevated temperature (ET) during the nongrowing season significantly increased the net photosynthetic characteristics. The strongest effects occurred during warming period from 1 December 2014 to 1 February 2015 (W1). Moreover, the carbohydrate concentration was elevated due to the warming during W1, but it declined during four months of the warming (from 1 December 2014 to 1 April 2015, W2). The seedlings kept under N deposition (CN) showed a positive effect in all the above-mentioned parameters except δ13C. Significant interactions between ET and N deposition were observed in most parameters tested. At the end of the experiment (W2), the seedlings exposed to a combined ET and N deposition treatment exhibited the highest carbon contents. Our results showed that N deposition might ameliorate the negative effects of the winter warming on the carbon content., L. Yu, T. F. Dong, Y. B. Lu, M. Y. Song, B. L. Duan., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7638. Ecophysiological responses of different density maíze stands under drought stress and during recovery
- Creator:
- Nagy, Z., Tuba, Z., and Csintalan, Zs.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Net photosynthesis (Pn)> transpiration (£) and water use efficiency (WUE) responses to prolonged drought and subsequent recovery after rewatering were investigated in sun and shade leaves of two maize (Zea mays L. cv. Pioneer 3839 SC) stands with different plant density (6.2 and 10.8 plants per m^). Drought stress was induced by the very smáli amount of precipitation (60 mm) during the 57 d of the study period. was higher in both sun and shade leaves in the low density stand through the study period, presumably owing to higher degree of intraspecific competition in the denser stand. did not decrease under severe drought stress in the sun leaves of the two stands. WUE decreased in sun leaves in both stands. decreased most in the shade leaves of the high density stand, due to less available radiation in this stand. The higher degree of intraspecific competition might also contribute to this. The short- and long-term responses by the stands to irrigation differed greatly, as WUE decreased in the high density stand and increased in the low density stand. Thus was more strongly affected in the high density stand because of the higher degree of interactive drought stress and intraspecific competition concurrently with considerable loss of stomatal control of E.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7639. Ecophysiological responses of Eichhornia crassipes (Mart.) Solms to As5+ under different stress conditions
- Creator:
- Meneguelli-Souza, A. C., Vitória, A. P., Vieira, T. O., Degli-Esposti, M. S. O., and Souza, C. M. M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, carotenoid, chlorosis, remediation, senescence, trace element, 2, and 581
- Language:
- Multiple languages
- Description:
- Arsenic is a critical contaminant that is released into the environment through geochemical processes and anthropic actions. Two independent hydroponic experiments were performed to evaluate the ecophysiological responses of water hyacinth [Eichhornia crassipes (Mart.) Solms] to As under various stress conditions. In experiment 1, water hyacinth was exposed to As5+ at concentrations of 0, 0.2, 2.0, and 20 mg L-1 for 0, 2, and 4 d; in experiment 2, water hyacinth was exposed at concentrations of 0, 0.025, 0.05, and 0.1 mg L-1 for 0, 10, and 20 d. In both experiments, As accumulation in plant tissue was proportional to its increase in the nutrient solution; As concentrations were higher in roots than in shoots. Detrimental effects of As on gas exchange were observed and were more pronounced in experiment 1. In experiment 1, at the beginning on the second day of exposure, significant decreases of maximum photochemical efficiency of PSII (Fv/Fm), variable chlorophyll fluorescence (Fv/F0), and photosynthetic pigment contents were observed in plants exposed to 2.0 and 20 mg(As5+) L-1. It indicated that damage to the photosynthetic apparatus had occurred. No changes in Fv/Fm, Fv/F0, and contents of photosynthetic pigments were observed in the plants grown in the presence of 0.2 mg(As5+) L-1 (in experiment 1) or after any of the treatments in experiment 2, indicating plant tolerance. Elevated nonphotochemical quenching was observed in experiment 2 after 20 d of exposure to As; it was as a part of protection mechanisms of the photosynthetic apparatus in these plants. The results obtained here indicate that the use of water hyacinth for As5+ removal from highly impacted environments is limited but that it is effective in remediating sites with a low contamination., A. C. Meneguelli-Souza, A. P. Vitória, T. O. Vieira, M. S. O. Degli-Esposti, C. M. M. Souza., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
7640. Ecophysiological responses of native invasive woody Juniperus virginiana L. to resource availability and stand characteristics in the semiarid grasslands of the Nebraska Sandhills
- Creator:
- Msanne, J., Awada, T., Bryan, N. M., Schacht, W., Drijber, R., Li, Y., Zhou, X., Okalebo, J., Wedin, D., Brandle, J., and Hiller, J.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fluorescence, karboxylační rychlost, východní červený cedr, transport elektronů, výměna plynu, půdní živiny, jalovec viržinský, carboxylation velocity, eastern red cedar, electron transport, gas exchange, isotope ratio, soil nutrients, 2, and 581
- Language:
- Multiple languages
- Description:
- Vegetation in grasslands is changing at an unprecedented rate. In the Nebraska Sandhills, this shift is attributed in part to encroachment of the woody species Juniperus virginiana. We investigated changes in resource availability and their feedback on seasonal trends in photosynthetic characteristics of J. virginiana trees scattered in open grasslands vs. a dense 57-year-old stand. Dense stand exhibited lower volumetric soil water content, NH4+, NO3-, and δ13C, as well as foliage δ13C, δ15N, and N content, compared to grasslands. Water potential was higher in trees in grasslands compared to dense stand. J. virginiana in dense stand exhibited similar trends to trees in grasslands for net photosynthetic rate (PN), stomatal conductance, transpiration, maximum photochemical efficiency of PSII, maximum carboxylation velocity, and maximum rate of electron transport. PN peaked early summer and declined in the fall, with trees in open grasslands lagging behind those in dense stand. Plasticity of this species may place it at a competitive advantage in the Sandhills, further altering grasslands vegetation and ecosystem processes., J. Msanne, T. Awada, N. M. Bryan, W. Schacht, R. Drijber, Y. Li, X. Zhou, J. Okalebo, D. Wedin, J. Brandle, J. Hiller., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public