New localities and syntaxonomic characteristics of sea buckthorn (Hippophaë rhamnoides L., Elaeagnaceae) in Croatia

Pasji je trn glacijalni relikt, koji se je nakon povlačenja ledenoga pokrova širio prema sjeveru i višim planinskim po­lo­žajima. U Hrvatskoj je bio rasprostranjen u Međimurju i u Podravini (uz Muru i Dravu – Legrad, Bukovec, Dubra­va, Križovljan-grad). Vrlo je rijedak i u uzgoju ili subspontano proširen, te se još navodi i za područje Samobora, Skra­di­na, a u uzgoju je još zabilježen u Botaničkome vrtu Prirodoslovno-matematičkoga fakulteta Sveučilišta u Zagrebu, Nespešu, Starom Brestju (Sesvete), uz brzu cestu Sv. Helena-Bjelovar i u Park-šumi Adica u Vukovaru. Tijekom prve polovice 20. stoljeća nije bilo nikakvih novih podataka o rasprostranjenosti pasjega trna u Hrvatskoj, a u dru­goj polovici 20. stoljeća, tijekom fitocenoloških istraživanja vegetacije u priobalnome pojasu rijeke Drave u široj varaždinskoj okolici Trinajstić (1964, 1994) bilježi nekoliko grmova, bez posebne fitocenološke pripadnosti. Za Hrvatsku prve podatke o fitocenološkim značajkama vrste H. rhamnoides donosi Trinajstić (2006) i to na osnovi jedne fitocenološke snimke iz koje se može jasno razabrati da ona prema svom florističkom sastavu pripada u sintaksonomskom smislu as. Hippophao-Berberidetum Moor 1958.Najnovijim istraživanjima sukcesije vegetacije u Podravini, 26. lipnja 2015. godine utvrđeno je novo nalazište vrste H. rhamnoides sjeverno od sela Veliki i Mali Bukovec (46.3070540, 16.7275400). Napravljena je jedna fitocenološka snimka (Tab. 1). Analizom fitocenološke snimke vidljivo je da je ona bogatija vrstama (25 : 15) od fitocenološke snimke Trinajstić-a (2006) i vrlo je slična snimkama Moor-a (1958). Dosad je Trinajstić-ev (2006) nalaz pasjega trna iz 1966. godine bio posljednji zabilježeni nalaz ove vrste u Hrvatskoj. Kako su hidrološkim zahvatima uništena staništa i kako je pasji trn nestao s toga prostora novi nalaz pasjega trna i nalaz as. Hippophao-Berberdetum Moor 1958 (Berberidion vulgaris Br.-Bl. 1950) su jedini postojeći prirodni nalazi. Iz tih razloga potrebno je naglasiti da je hrvatska flora sada bogatija za jednu vrstu prirodno rasprostranjenu, a i vegetacija Hrvatske je bogatija za jednu asocijaciju kojima treba dati odgovarajuće prirodoznanstveno značenje.Common sea-buckthorn is a glacial relict, which was, after the last glaciation, spreading to the north and higher mountain positions. In Croatia, it was widespread in Međimurje and Podravina (near Mura and Drava river – Legrad, Bukovec, Dubrava, Križovljan-grad). It is very rare in cultivation or sub-spontaneous spread, some sites are referred to the ​​Samobor and Skradin area, and cultivated it can be found in the botanical garden of the Faculty of Science, University of Zagreb, Nepeš, Staro Brestje (Sesvete), by the road Sv. Helena-Bjelovar and in the Forest Park Adica in Vukovar. During the first half of the 20th century there was no new information on the distribution of sea buckthorn in Croatia, and in the second half of the 20th century, during the phytosociological survey of vegetation in the coastal zone of the river Drava in the wider Varaždin surroundings Trinajstić (1964, 1994) records several shrubs, without special phytosociological affiliation. As for Croatia, the first data on phytosociological features of the species H. rhamnoides brings Trinajstić (2006), based on one phytosociological relevé which, according to its floristic composition, in syntaxonomic terms belongs to the Ass. Hyppophao-Berberidetum Moor 1958.The latest research on vegetation succession in Podravina, 26th of June 2015, showed a new locality of H. rhamnoides, north of the villages Veliki and Mali Bukovec (WGS84 Lat: 46.307054, Long: 16.727540). One phytosociological relevé was made (Tab. 1). The analysis of the relevé shows a greater species richness (25, 15) compared to the one of Trinajstić’s (2006) and is very similar to the relevé of Moore’s (1958). So far Trinajstić-s (2006) finding of sea-buckthorn in 1966 was the last recording of this species in Croatia. As the hydrological interventions destroyed the habitats, causing the sea-buckthorn to disappear from this area, the new records of sea-buckthorn and Ass. Hyppophao-Berberdetum Moor 1958 (Berberidion vulgaris Braun-Blanquet 1950) are the only existing natural findings there. For these reasons, it should be noted that the Croatian flora is now richer for one naturally spread species, as well as the vegetation of Croatian is richer for one association which should be given an adequate importance in natural science

Emulsifying properties of hemp proteins: Effect of isolation technique

peer-reviewedHemp protein was isolated from hemp seed meal using two different isolation procedures: alkali extraction/isoelectric precipitation (HPI) and micellization (HMI). The ability of these proteins to form and stabilize 10% (w/w) sunflower oil-in-water emulsions (at pH = 3.0) was studied at three different concentrations, 0.25, 0.75 and 1.5% (w/w), by monitoring emulsion droplet size distribution, microstructural and morphological properties, rheological behaviour and stability against flocculation, coalescence and creaming. In addition, hemp proteins were analysed for water solubility, denaturation degree and surface/interfacial activity. HMI protein, which was found to be less denatured after isolation, exhibited higher solubility and slightly higher surface/interfacial activity than HPI protein. HMI emulsions possessed a smaller volume mean droplet diameter (d4,3 = 1.92–3.42 μm in 2% SDS) than HPI emulsions (d4,3 = 2.25–15.77 μm in 2% SDS). While HMI stabilized emulsions were characterized with individual droplets covered by protein film, both confocal laser scanning microscopy and flocculation indices indicated occurrence of bridging flocculation in HPI stabilized emulsions. Protein aggregation, which induced flocculation of the droplets, contributed to higher apparent viscosity of HPI stabilized emulsions compared to HMI stabilized emulsions. Interestingly, emulsions stabilized with 1.5% (w/w) HPI exhibited much better creaming and coalescence stability than other emulsions due to the formation of a weak transient network of floccules and higher continuous phase viscosity which both suppressed the movement of the droplets

Phytosociological analysis of beech forests in the Žumberak and Samobor highlands (Croatia)

The Žumberak and Samobor highlands are situated in the north-western part of Croatia where the characteristics of the Dinarides, the Alps and the Pannonian Plain meet. The greater part of the area is occupied by beech forests. The aim of the study was to determine the syntaxonomic affiliation of these forest communities, and to explore their floristic and main ecological features. Numerical analyses of floristic compositions were conducted on a data-set consisting of 144 new relevés and 99 relevés from the existing literature. Relevés were made following the standard Braun-Blanquet method. For descriptions of ecological conditions Ellenberg’s indicator values were used. Six plant associations and two subassociations of beech forests were established in Luzulo-Fagion and Aremonio-Fagion alliances. The higher altitudes of the studied area are occupied by ass. Cardamini savensi-Fagetum, whereas the lower altitudes are occupied by ass. Lamio orvalae-Fagetum and Hacquetio-Fagetum. Ass. Hacquetio-Fagetum spreads on southern slopes and ridges, whereas ass. Lamio orvalae-Fagetum occurs in ditches and on northern slopes. In the warmer habitats with shallow soils on a dolomite base ass. Ostryo-Fagetum occurred. A small part of the area is characterized by silicate substrate which is occupied by ass. Luzulo-Fagetum and Gentiano asclepiadeae-Fagetum

Conductometric study of sodium dodecyl sulfate - nonionic surfactant (Triton X-100, Tween 20, Tween 60, Tween 80 or Tween 85) mixed micelles in aqueous solution

The present study is concerned with the determination of the critical micelle concentration (cmc) of mixed micelles of sodium dodecyl sulfate with one of five nonionic surfactants (Triton X-100, Tween 20, Tween 60, Tween 80 or Tween 85) from conductance measurements. Based on the calculated values of the β parameters we have noticed that SDS-nonionic surfactants mostly showed strong synergistic effect. It was found that nonionic surfactants with mainly longer and more hydrophobic tail show stronger interactions with hydrophobic part of SDS, thus expressing stronger synergism. In SDS-Tween 80 binary system the strongest synergistic effect was noticed. SDS-Tween 85 micellar system showed antagonistic effect, most probably because the presence of the double bond in its three hydrophobic tails (three C18 tails) makes it sterically rigid

Photosyntesis Intensity andVegetative Growth of Pedunculate Oak (Quercus roburL.) in Common-Garden Experiment

U radu je analiziran utjecaj mikrostaništa na fiziološke značajke i vegetativni rast hrasta lužnjaka. Istraživanje je provedeno na dvije pokusne plohe koje se odlikuju različitim kemijskim značajkama, sadržajem vlage i temperaturom tla. Cilj rada bio je utvrditi utjecaj različitih kemijskih značajki tla na vegetativni rast i intenzitet fotosinteze hrasta lužnjaka, kao i odnos koncentracije klorofila i intenziteta fotosinteze. Biljke uzrasle na tlu s većom koncentracijom humusa, dušika, fosfora i kalija imaju veći intenzitet fotosinteze, veću koncentaraciju klorofila te bolji vegetativni rast. Zbog povoljnog odnosa volumetrijskog sadržaja vlage u tlu i vodnog potencijala istraživanih biljaka, njihov značajniji utjecaj na fiziološke i vegetativne značajke hrasta lužnjaka nije utvrđen. Rezultati ukazuju na visoku pozitivnu korelaciju između indeksa ukupnih klorofila u proljetnim listovima i većine fizioloških te vegetativnih značajki istraživanih biljaka.The effect of various types of environmental stress factors on forest trees is most often manifested through the reduced absorption of mineral nutriments. This results in lowered efficiency of photosynthetic pigments on the leaf’s cellular level and production of insufficient amounts of carbohydrates necessary for normal vegetative growth. Due to sudden increase in concentration of carotenoids in relation to chlorophyll, which is susceptible to a sudden destruction under the effect of stress factors, a change takes place in the relative amounts of chlorophyll and carotenoids. Because of this, the leaves in the crown of a tree temporarily lose their green color and turn yellow, which is indicative of plant’s lack of nitrogen nutrition, i.e. the nitrogen deficiency in the soil. The role of nitrogen as a plant nutriment is connected with numerous physiological processes responsible for successful growth and development of plants. For example, nitrogen is an essential element responsible for an uninterrupted continuation of photosynthetic process and vegetative plant growth, primarily because of its role in the synthesis of chlorophyll and certain proteins, such as ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco), which is responsible for CO2assimilation. In the previous studies of forest trees, significant differences were determined in the intensity of photosynthesis and vegetative development regarding the diverse conditions in the habitats. These variations are usually due to the lengths of summer droughts and high temperatures, the intensity of illumination, and the differences between dry and wet years. The aim of this study was to, (1) determine the effect of various chemical characteristics of the soil on the intensity of photosynthesis and the vegetative growth of pedunculate oak, (2) establish a connection between content index of the total amount of chlorophyll in the leaf, and the intensity of photosynthesis and the vegetative growth of pedunculate oak. The study was conducted during the vegetative period in 2010, on 4-yearold plants, planted with 2 – 2,5 meters of space between plants. Based on visual differences in the leaf color, two plots have been set aside – the chlorotic and the control plots (without chlorosis). Each field contained 8 plants, i.e. 16 in total. The average height of the plants under study before the start amounted to 1.96 ± 0.44 meters, and the diameter of the trunk 2.5 centimeters, measured 30 centimeters above ground. In order to determine the differences in the soil’s chemical characteristics between the two studied plots, the samples were taken on the depth of 0–30 centimeters. The soil reaction was determined with a potentiometer in the suspension of soil and water, i.e. soil and nKCl. Humus was determined by the Thorin method, and the total nitrogen level by the Kendahl method. The content of physiologically active phosphorus and potassium was determined by the Al-method. The study determined height and diameter increment for the plants studied, and also height and diameter increment for primary branches of each plant. The number of spring and summer shoots with its attending leaves was also determined. Based on the number and surface area of leaves, as well as the projection of crown surface on the ground, index of leaf surface was calculated for each tree. The measurements of photosynthesis intensity and the index of total chlorophyll content were performed early in September. The photosynthesis intensity was measured with the help of the infrared gas analizer portable device LCpro + (ADC BioScientific). While taking photosynthesis intensity measurements, each leaf was subjected to illumination intensity of 1500 µmol m-2 s-1, CO2concentration of 380 ± 10 µmol mol-1and the air temperature of 25 ± 2 °C. The chlorophyll content index was determined by using chlorophyll content meter CCM-200. By using a portable chamber for measuring water potential, the measurement of water potential was taken in the leaves (.) of plants under study. The chemical characteristics of the soil in the test plots were shown in Table 1. There was an extremely acidic reaction in the chlorotic plot, and acidic in the control plot. The chlorotic plot was marked by an extremely low nitrogen supply, while the control plot had a medium to good nitrogen supply. The content of physiologically active phosphorus in the chlorotic plot was extremely low, while the control plot was averagely supplied with physiologically active phosphorus. Both plots under study featured accessible potassium levels on the lower margins of an average supply. The humus content in the studied plots was very low, especially in the chlorotic plot. Statistically significant difference in the measured values of water potential of the plants grown in the plots was determined only during noon measuring throughout July. In August and September, statistically significant differences in the measured values of water potential were not determined (Table 3). All the parameters of the vegetative growth of the plants under study which were grown on the control plot had statistically significant higher values compared to the plants grown on the chlorotic plot, except for the number of primary branches, which showed no statistically significant differences between the two studied plot trials (Table 4). Leaf surface index, value of which was taken in the middle and near the end of the vegetative cycle, was statistically significantly higher in the control plot than in the chlorotic plot (Figure 2). There was statistically significant difference in the intensity of photosynthesis measured on spring leaves of studied plants between the control and the chlorotic plot. The intensity of photosynthesis on the control plot was 28.4 µmol CO2m-2 s-1, while its value on the chlorotic plot was 19.3 µmol CO2m-2 s-1. Content index values of total chlorophyll in the leaves of the studied plants were statistically significantly different regarding the plots under study, no matter whether the measuring of chlorophyll content was conducted on spring or summer leaves (Figure 4). Regression analysis determined a high positive correlation between the content index of total chlorophyll measured on spring leaves of studied plants with the intensity of photosynthesis, leaf surface index, tree’s girth increment, and also length and girth increment in the primary branches (Table 5). The correlation between content index of total chlorophyll and tree’s height increment was very weak. The results of the study indicate that the soil’s chemical characteristics have an effect on the photosynthetic activity and the concentration of chlorophyll in the leaves of pedunculate oak. The higher values of the total chlorophyll’s content index and the intensity of photosynthesis were recorded for plants grown on the soil with a higher concentration of humus, nitrogen, phosphorus and potassium. Positive correlations between the content indexes of total chlorophyll in leaves and the intensity of photosynthesis, as well as most of the parameters of vegetative growth, indicate the possibility of successful application of chlorophyll measuring methods when determining vitality of particular trees and forest stands of pedunculate oak

Physical properties of dough for cookies with chestnut flour

A challenge for food producers is certainly to find suitable flour that can replace wheat flour in the production of flour–based products. Chestnut flour can be adequate substitute for wheat flour in the production of gluten–free flour confectionary products, due to high starch and sugar content. The objective of this work was to characterize physical changes, rheological and textural properties of dough for cookies with chestnut flour. The control dough was only with wheat flour. The substitution of wheat flour with chestnut flour for examined dough samples was at three different levels (20, 40 and 60%). Moisture of the dough was 22%.Dynamic oscillatory measurements describe all dough samples as typical viscoelastic systems with dominant elastic modulus G' over viscous modulus G". The modulus ratio (tan δ=G"/G') decreased with increase in amount of chestnut flour. Also, the dough compliance (J) determined by creep and recovery curves decreased, thus more chestnut flour resulted in more brittle consistency of the dough. Texture determination confirmed the rheological results. Resistance to extension of the control dough sample was the highest, as well as dough extensibility. Application of chestnut flour and increase in its amount reduced these texture parameters for dough samples. Optimal physical properties of dough were achieved with low amounts of chestnut flour of 20%