Christos Lykas | UNIVERSITY OF THESSALY, GREECE (original) (raw)

Papers by Christos Lykas

Horticulturae

Aiming at evaluating new candidate species for the cut flower market of Greece and beyond, in thi... more Aiming at evaluating new candidate species for the cut flower market of Greece and beyond, in this study, the vase life of three Greek tulip plant species, Tulipa cretica ‘Hilde’ (CRH, local endemic of Crete, Greece), T. clusiana ‘Chrysantha’ (CLC, naturalized in Chios Island, Greece), and T. australis (AUS, native in the Mediterranean and Greece), was investigated in comparison to the commercial tulip hybrid Île-de-France (IDF). To this end, pre-cooled at 4 °C bulbs of the abovementioned Greek tulip plant species were bought from Dutch nurseries and grown in pots placed in unheated greenhouses located at two different climatic conditions in Northern Greece. The plants were uprooted when the flowers reached a slightly open stage. Half of the flowering stems were immediately placed into bottles with deionized water, while the rest were placed in a preservative solution containing citric acid 5% and sulfuric acid 1% and then remained under laboratory conditions until the entire tepal ...

International Symposium on High Technology for Greenhouse Systems: GreenSys2009, 2011

Bioresource Technology Reports

International Journal of Agriculture & Environmental Science

Proceedings of the 16th IFAC World Congress, 2005, 2005

FCT/MEC e FEDER (POCI-01-0145-FEDER-007265) pelo apoio financeiro ao REQUIMTE e pela bolsa de A. ... more FCT/MEC e FEDER (POCI-01-0145-FEDER-007265) pelo apoio financeiro ao REQUIMTE e pela bolsa de A. Fernandes (REQUIMTE 2016-13).

Ozonation as an alternative method for the disinfection of dried herb material shows promising re... more Ozonation as an alternative method for the disinfection of dried herb material shows promising results concerning the microbial load reduction. However, there is not enough data about the effect of the method on the essential oil quality. The aim of this study was to investigate the effect of ozone on the essential oil content and composition of dried oregano, thyme and lemon verbena. Quantitative and qualitative essential oil measurements were performed before and after ozonation. The results showed that in cases of oregano and lemon verbena, no statistically significant difference was observed either in total essential oil content or on any of their compound concentration. However ozonation may affect the concentration of some components since in the case of thyme the concentration of 8 compounds decreased.

In this study was investigated the effect of manure and cocoa shell biomass addition on soil che... more In this study was investigated the effect of manure
and cocoa shell biomass addition on soil chemical
properties and microflora, when the above mentioned
organic materials areused in different proportions in
soil mixtures. For this reason different amounts (0.2,
0.4, and 0.6g) of air dried cocoa beans residue, were
mixed with 50g of soil and 5.0g of manure. The
control mixtures that contained only soil and manure
as well as the mixtures which contained different
amount of cocoa shells, were placed in incubator at
28oC for a period of 21 weeks. The organic matter
and the concentration of nutrient elements in the soil,
manure, cocoa shells biomass and in their mixtures,
were measured before and after the incubation
period. The results showed that the addition of more
than 1% of cocoa shell biomass to soil-manure
mixtures, may influence the mineralization of N, C
and K, and reduce the time needed for mixtures
maturation. The higher organic P content measured
in mixtures contained lower than 1% cocoa shell
biomasswhere the microbial activity was still high.
However the concentration of the available P was not
affected from the addition of cocoa shell biomass to
the soil-manure mixtures.

Controlled release fertilizers (CRFs) insure controlled release of nutrients due to their coating... more Controlled release fertilizers (CRFs) insure controlled release of nutrients due to their coating. The aim of this study was to investigate the effect of nutrient solution parameters as well as time on the evolution of NO3, NH4, PO4 and K concentrations. For this reason, 0.5 g of Multicote fertilizers 14-14-14 and 15-7-15 dissolved in 100 mL and 300 mL of deionized water respectively. The solutions remained at 24C and their pH was adjusted once during their preparation at 5.5, 6.0 and 6.5 or adjusted every three days for a 24 days period. A linear empirical mathematical model was developed for the prediction of the above mentioned nutrients concentrations (CX) in relation to the remaining (Vs) and the removed (dVs) volume of the nutrient solution, its pH and time (t) from its preparation. The model output compares favorably with data for the prediction of the concentration of these nutrients.

From an ornamental viewpoint, tulips are famous clonally propagated crops. This research focuses ... more From an ornamental viewpoint, tulips are famous clonally propagated crops. This research focuses on 15 wild-growing Greek tulip species including 11 range-restricted species, i.e., six Greek endemics and five Balkan or Aegean endemics and subendemics, among which seven are currently threatened with extinction (two Critically Endangered, three Endangered and two Vulnerable). An overview of the global electronic trade over the internet is presented herein for these valuable phytogenetic resources in an attempt to define the extent of their commercialization (25 nurseries in three countries, mainly bulb trade at various prices) with concomitant conservation implications. In the frame of the repatriation initiatives launched, their global ex situ conservation is overviewed according to the PlantSearch facility of the Botanic Gardens Conservation International (materials from 15 species stored in 41 botanic gardens of 14 countries). The results of this study on the Greek tulips showed th...

Journal of Horticultural Science and Biotechnology

This study investigated the effect of light and agitation on the availability of iron in hydropon... more This study investigated the effect of light and agitation on the availability of iron in hydroponic nutrient solutions. In recycled hydroponic nutrient solutions used for the cultivation of roses, iron is added usually in the form of chelate fertilizers, such as Fe-EDDHA. In practice, the concentration of iron in the nutrient solution in those systems reaches low critical levels very rapidly (in less than 2 d). Fe-chelates are unstable in light and can form soluble or insoluble precipitates. Iron contained in soluble precipitates can be recovered in the solution by agitation. In contrast, iron contained in insoluble precipitates cannot be recovered. The tank of the closed-loop fertigation system used to grow a rose crop was filled with fresh nutrient solution every 10 d. Immediately after preparing each solution, four 11 plastic bottles were filled with the solution and kept in light or in the dark (two bottles of each), at the same temperature. For the next 10 d the concentration o...

Agronomy

Thermography is a technique based on infrared imaging, which is used nowadays to detect plants un... more Thermography is a technique based on infrared imaging, which is used nowadays to detect plants under stress caused by biotic and abiotic factors. In many cases, temperature changes have already been correlated with pathogen attacks. In this sense, thermography offers the ability of early disease detection in plant pathology. In this work, a low-cost AMG8833 Grind-Eye infrared camera combined with a 1080P RGB web camera was used to develop an integrated infrared and RGB imaging system, to record temperature changes on vine, chrysanthemum, and rose plant leaf surfaces. Vine and chrysanthemum leaves were infected with Phomopsis viticola and Septoria ssp. respectively, respectively, whereas rose plants leaves were infected with Colletotrichum spp. as well as with Podosphaera pannosa. Measurements were performed using the integrated imaging system on infected and uninfected leaves, as well as on PDA plates with active and non-active mycelium. According to the results, vine leaf tissue in...

International Conference on Sustainable Greenhouse Systems - Greensys2004, 2005

Plant foods for human nutrition (Dordrecht, Netherlands), Jan 28, 2015

Common purslane (Portulaca oleracea L.) is an annual weed rich in omega-3 fatty acids which is co... more Common purslane (Portulaca oleracea L.) is an annual weed rich in omega-3 fatty acids which is consumed for its edible leaves and stems. In the present study six different genotypes of common purslane (A-F) were evaluated for their nutritional value and chemical composition. Nutritional value and chemical composition depended on genotype. Oxalic acid content was the lowest for genotype D, whereas genotypes E and F are more promising for commercial cultivation, since they have low oxalic acid content. Genotype E had a very good antioxidant profile and a balanced composition of omega-3 and omega-6 fatty acids. Regarding yield, genotype A had the highest yield comparing to the other genotypes, whereas commercial varieties (E and F) did not differ from genotypes B and C. This study provides new information regarding common purslane bioactive compounds as affected by genotype and could be further implemented in food industry for products of high quality and increased added value.

Spanish Journal of Agricultural Research, 2014

Acta horticulturae

The objective of this work was to quantify temporal changes of NO3-, PO43- and SO42- concentratio... more The objective of this work was to quantify temporal changes of NO3-, PO43- and SO42- concentration on leaves, shoots and roots of rose plants during a short growing period, in response to air temperature, light intensity and the concentration of the above mentioned anions in the nutrient solution. For this reason rose plants (×Rosa hybrid ‘Iceberg’) were placed in a glasshouse during September 2004 and grown in nutrient solution according to the Deep Flow Technique (DFT). The plants were pruned in order to develop one main flower shoot. Measurements were performed during December 2004. The concentration of NO3-, PO43- and SO42- (mg L-1) in the nutrient solution and in different plant parts (mg kg-1) as well as the fresh (fw) and dry (dw) weight of leaves, shoots and roots were measured every day, by destructive sampling of 6 plants each time, for a period of 28 days. In addition during the same period the greenhouse air temperature and the intensity of the incoming solar radiation w...

A network of hardwired conventional sensors have been used traditionally for sensing, monitoring ... more A network of hardwired conventional sensors have been used traditionally for sensing, monitoring and control of the climate in greenhouses and fertigation of the crop. However, in recent years due to the introduction of new cultivation methods, e.g. hydroponics, the number of required sensors in greenhouse installations has increased drastically and their associated monitoring and control has become complex. In addition, the extensive wiring of the sensor network has increased the requirements for system maintenance and measurement errors. The development and application of wireless embedded sensors for monitoring and control of hydroponic systems can result in reduction of measurement errors, easy expansion of the sensor network system, reduction in the cost of system installation and its maintenance and safe data transfer. In addition, the use of embedded computer systems and appropriate software can provide flexibility and reliability in measuring and controlling the parameters o...

Purslane is considered as an important weed that severely affects crop production. However, nowad... more Purslane is considered as an important weed that severely affects crop production. However, nowadays there is increasing interest in purslane commercial cultivation as a vegetable species due to its high content in omega-3 fatty acids. In a field experiment that was carried out at the experimental field of the University of Thessaly in Velestino within the period of May-July 2014, the growth and yield of three genotypes of purslane (Portulaca oleracea L.) were evaluated. The experimental design was a completely randomized design with four replicates per treatment. The treatments were three different genotypes of common purslane: i) genotype A (local population from “Domokos” region), ii) genotype B (commercial cultivar Common purslane from Gemma S.A.) and iii) genotype C (commercial cultivar Purslane Dark Green). The measurements (height, internode length, leaf length and width, yield, total soluble solids (TSS) content, chlorophyll content and photosynthetic rate) were repeated twi...