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Roussos P.A.,Agricultural University of Athens | Gasparatos D.,Aristotle University of Thessaloniki | Kechrologou K.,Agricultural University of Athens | Katsenos P.,Agricultural University of Athens | Bouchagier P.,Technological Educational Institution of Ionian Islands
Scientia Horticulturae | Year: 2017

The aim of the present research was to investigate the effect of two commercial organic fertilizers (Activit and Agrobiosol) on two newly planted olive cultivars for two successive years. Two cultivars were used, ‘Koroneiki’ an olive oil cultivar and “Konservolia” a table olive one. The organic fertilizers were combined with inorganic fertilizers which when used alone served as control. Organic fertilizer application resulted in lower soil pH values (8.0–8.15 compared to 8.46 in control) and higher cation exchange capacity (up to 19.6 meq 100 g−1 compared to 17.1 meq 100 g−1 in control). Soil N, K, Mn and Zn concentration were higher under the combined application of Activit plus inorganic fertilizer. A significant increase of leaf area index was observed when organic fertilizers were used. Nutrient concentrations of the leaves were in all treatments within the adequacy range. Carbon assimilation rate also increased under organic fertilization in ‘Koroneiki’ in summer (17.4–18.7 μmol m−2 s−1) compared to control (14.9 μmol m−2 s−1). Yield of ‘Koroneiki’ trees during the second year (the only cultivar bearing fruits) was higher under both organic fertilizers application, reaching almost 55% increase compared to the use of only inorganic fertilizer. © 2017 Elsevier B.V.


Filippou P.,Cyprus University of Technology | Bouchagier P.,Technological Educational Institution of Ionian Islands | Skotti E.,Technological Educational Institution of Ionian Islands | Fotopoulos V.,Cyprus University of Technology
Environmental and Experimental Botany | Year: 2014

Ailanthus altissima (Miller) Swingle (family Simaroubaceae), commonly known as the 'Tree of Heaven', grows aggressively in harsh environments where it invades abandoned fields or cracked city sidewalks. The present study deals with the adaptation of defence mechanisms of A. altissima seedlings subjected to two of the most important abiotic stress factors worldwide, drought and salinity. Salinity-stressed A. altissima seedlings were obtained by watering the plants with two different NaCl concentration solutions (150 and 300mM) for 48h, while drought-stressed plants were obtained after withholding watering for 14d. Physiological parameters, reactive oxygen/nitrogen species and malondialdehyde content measurements in stressed plants indicated the abiotic stress factor-specific regulation of its defence response. Moreover, the content of the osmoprotective molecule proline was also affected by both stresses in parallel to the oxidative/nitrosative markers. Nitrate reductase enzymatic activity and protein content involved in nitric oxide biosynthesis, δ1-pyrroline-5-carboxylate synthetase enzymatic activity involved in proline biosynthesis, as well as the activity of H2O2-generating and scavenging enzymes (superoxide dismutase and catalase, respectively), provided further biochemical support for the specific abiotic stress tolerance mechanism of this invasive plant species. © 2013 Elsevier B.V.


Bouchagier P.,Technological Educational Institution of Ionian Islands | Efthimiadis P.,Agricultural University of Athens
Journal of Agronomy | Year: 2010

The aim of the study was to investigate the influence of bermudagrass on growth components, physiology parameters (stomatal aperture, leaf transpiration, carbon dioxide intake, leaf temperature, Fv/Fm values and net assimilation rate) and concentration of important nutrients (N, P, K, Mg, Ca) in leaves and roots of cotton. Cotton seedlings and bermudagrass plantlets were growing adjacently in a Hoagland's nutrient solution of 1/2 strength, which was continuously circulated. Under the influence of bermudagrass, cotton suffered significant reduction of stomatal aperture, leaf transpiration, CO2 intake, Fv/Fm values, net assimilation rate and significant increase in leaf temperature. No differences were recorded between control and treatment in nutrient concentration in leaves. On the contrary, in cotton roots due to the influence of bermudagrass, Mg was increased by 29.2, P by 63.2 and Ca by 297.4%. Consequently the growth of plants in treatment was significantly inferior than control. Reduction was recorded at 54.6% for stem dry matter, at 35.5% for stem diameter, at 55.3% for leaves dry matter and 46.2% for root dry matter. Growth inhibition and deterioration of photosynthesis components (specifically Fv/Fm values) indicate that cotton suffered serious allelopathic stress due to the weed influence. Stress effect was pronounced although plants were growing in the nutrient solution, were no adverse factor to limit growth was observed. The allelopathic effect was exhibited by the weed, although it was not stressed in the nutrient solution. Dilution of allelochemicals in a high volume solution didn't reduce activity of allelochemicals. © 2010 Asian Network for Scientific Information.


Beneki C.,Technological Educational Institution of Ionian Islands | Eeckels B.,Les Roches-Gruyère University of Applied Sciences | Leon C.,University Center
Journal of Forecasting | Year: 2012

We present and apply singular spectrum analysis (SSA), a relatively new, non-parametric and data-driven method for signal extraction (trends, seasonal and business cycle components) and forecasting of UK tourism income. Our results show that SSA slightly outperforms SARIMA and time-varying-parameter state space models in terms of root mean square error, mean absolute error and mean absolute percentage error forecasting criteria. Copyright © 2011 John Wiley & Sons, Ltd.

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