Effect of selected soil and relief vineyards parameters on grape and wine composition of \u27Merlot\u27 (Vitis vinifera L.) in Vipava Valley

Vinogradi na terasah predstavljajo pomembno kulturno dediščino. Zaradi visokih stroškov vzdrževanja, pomanjkanja strokovnih delavcev ter podnebnih sprememb smo želeli preučiti vpliv nagiba gojenja trt na terasah na kakovost vina in grozdja. V letih 2019 in 2020 se je na relativno majhnem območju s podobnimi mezoklimatskimi razmerami grozdje ter vino s teras in iz dolin razlikovalo. Ravninski vinogradi na dolinskem dnu in vinogradi na terasah so se razlikovali v talnih profilih ter morfologiji tal. Tla na terasah so vsebovala do 90 % skeleta, tla vinogradov dolin pa so bila neskeletna. V obeh letih so bile trte s teras v večjem sušnem stresu kot trte iz dolin. Trte teras so imele manjšo maso (2019: –48 %2020: –34 %) in število grozdov (2019: –31 %2020: –17 %), maso jagod (2019: –24 %2020: –9 %), manj pridelka (2019: –49 %2020: –33 %) ter večje razmerje med kožicami (2019: +78 %2020: +22 %) in pečkami (2019: +70 %2020: +25 %) ter pulpo. Temnejša barva pečk grozdja s teras je nakazovala na večjo fenolno zrelost. Vina s teras so imela v obeh letih večjo vsebnost skupnih polifenolov (2019: +12 %2020: +24 %), antocianinov (2019: +24 %2020: +67 %) in proantocianidinov (PAs2019: +37 %2020: +30 %) ter so bila senzorično bolje ocenjena (2019: +51 %2020: +74 %) kot vina iz vinogradov z dolin. V letu 2019 so imela vina manj prodelfinidinov (–14 %) in bila bolj galoilirana (+26 %). Vina s teras so vsebovala več višjih alkoholov ter manj estrov. Sveže kožice grozdja s teras so v obeh letih vsebovale več antocianinov in skupnih polifenolov, suhe kožice dolinskih vinogradov pa več nizkomolekularnih PAs ter so bile v letu 2019 bolj galoilirane ter v letu 2020 vsebovale več prodelfinidinov. Pečke grozdja teras so bile bolj galoilirane ter v letu 2019 vsebovale več skupnih polifenolov, PAs in nizkomolekularnih PAs. Pod enakimi eksperimentalnimi razmerami, kot so datum vzorčenja, standardizacija vinogradniških parametrov, so imela vina, pridelana na vinogradih s teras, boljši fenolni potencial in bila senzorično prepoznana kot boljša v primerjavi z vini ravnin. Razumevanje vpliva tal in rastišča na kakovost grozdja in vina je ključnega pomena za določanje najprimernejših vinogradniških leg vina merlot.Terraced vineyards hold cultural significance. Given high maintenance expenses, skilled labor scarcity, and climate shifts, we studied how terrace slope impacts wine and grape quality. In 2019 and 2020, grapes and wine from terraces and valleys differed in a relatively small area with similar mesoclimatic characteristics. Non–terraced vineyards in the valley floor and vineyards on terraces differed in soil profile and soil morphology. The soil on the terraces comprised as much as 90% skeleton, whereas the valley vineyards had a non–skeletal soil composition. In both years, the vines in the terraces were more affected by drought than the vines in the valleys. Grapes from all vineyards were harvested by hand and microvinified. The terrace vines had smaller, mass (2019: –48 %2020: –34 %) and number of clusters (2019: –31 %2020: –17 %), mass of berries (2019: –24 %2020: –9 %), lower yield (2019: –49 %2020: –33 %) and a higher ratio of skins (2019: +78 %2020: +22 %) to seeds (2019: +70 %2020: +25 %) and pulp. The darker color of the grapes from the terraces indicates a higher degree of phenol ripeness. In both years, the terrace wines had higher levels of total polyphenols (2019: +12 %2020: +24 %), anthocyanins (2019: +24 %2020: +67 %), and proanthocyanidins (PAs2019: +37 %2020: +30 %) and were sensory rated higher (2019: +51 %2020: +74 %) than the wines from the valley vineyards. In 2019, the wines had fewer prodelphinidins (–14 %) and were more galloylated (+26 %). The wines from the terraces contained more alcohol and less esters. Fresh grape skins from the terrace wines contained more anthocyanins and total polyphenols in both years, while dry skins from the valley wines contained more low–molecular weight PAs and were more galloylated in 2019 and contained more prodelphinidins in 2020. Grape skins from terraces were more galloylated in 2019 and contained more total polyphenols, PAs, and low–molecular weight PAs. Under the same experimental conditions (sampling date, standardization of vineyard parameters), wines from terraced vineyards exhibited better phenolic potential and were rated as better sensory than wines from non–terraced vineyards. Understanding the influence of soil and site on grape and wine quality is critical to determining the best vineyard sites suitable for Merlot wines

Resistance of surface and subterranean waterlice populations to water current

Podzemeljsko okolje in podzemeljske živali so zaradi ekstremnih razlik v okoljskih dejavnikih med podzemeljem in površjem odličen modelni sistem za preučevanje ekološke speciacije, tj. nastanka novih vrst zaradi divergentne naravne selekcije. Enakonožni rak vodni osliček, Asellus aquaticus, je podzemlje naselil večkrat neodvisno in ima še živeče površinske populacije. Med površinskimi in podzemeljskimi populacijami vodnega oslička genskega pretoka praktično ni, zato mora med njimi obstajati reproduktivna izolacija. Pri dveh površinsko-podzemeljskih parih populacij vodnih osličkov (Planinsko polje-Pivkin rokav Planinske jame, Cerkniško polje-Rakov rokav Planinske jame) smo izmerili sposobnost kljubovanja vodnemu toku in preverili ali bi ta lastnost lahko učinkovala kot reproduktivna bariera. Kritično hitrost vodnega toka (tj. hitrost toka, pri kateri oslička odplavi) smo izmerili 160 vodnim osličkom, po 20 samcem in 20 samicam iz vsake populacije. Podzemeljski oslički iz Pivkinega rokava so vzdržali hitrejši tok kot površinski oslički s Planinskega polja, med podzemeljskimi oslički iz Rakovega rokava in površinskimi oslički s Cerkniškega polja pa ni bilo razlike v kritični hitrosti vodnega toka. Obe podzemeljski populaciji sta imeli v primerjavi s površinskima večjo napovedljivost kritične hitrosti toka pri posamičnih osebkih. Razlika med obema podzemeljskima populacijama bi lahko bila posledica različnih hidroloških razmer v obeh rokavih Planinske jame. Razlike v sposobnosti kljubovanja vodnemu toku med ekomorfoma so verjetno premajhne, da bi lahko delovale kot reproduktivna bariera. Da bi ugotovili, ali so izmerjene razlike ključne za to, da se podzemeljski oslički v podzemlju obdržijo, površinski pa ne, bi morali izmeriti še hitrosti vodnega toka v naravnem habitatu populacij.Due to the extreme differences in environmental factors between subterranean and surface environments, subterranean habitats and animals therein are an excellent model system for studying ecological speciation, i.e. the origin of new species as side effect of divergent natural selection. The freshwater isopod crustacean waterlouse, Asellus aquaticus, has colonised the underground several times independently and has still living surface populations. There is practically no gene flow between surface and subterranean populations, suggesting a reproductive isolation must exist among them. In two surface-subterranean population pairs of waterlice (Planina Polje-Pivka River in Planina Cave, Cerknica Polje-Rak River in Planina Cave), we measured the ability of individuals to resist water current and checked if this trait could act as a reproductive barrier. Critical water current velocity (i.e. the velocity of water current at which waterlouse was washed away) was measured for 160 individuals, 20 males and 20 females from each population. The subterranean waterlice from Pivka River resisted a faster water current than the surface waterlice from Planina Polje, but no difference in the critical water current velocity was found between the subterranean waterlice from Rak River and the surface waterlice from Cerknica Polje. Individuals of both subterranean populations also had a higher predictability of the critical water current velocity compared to surface individuals. We assume that differences between both subterranean populations may be a consequence of different hydrology of Pivka and Rak River in Planina Cave. The differences between ecomorphs are probably too small to function as a reproductive barrier. To determine whether the measured differences are crucial for keeping the subterranean waterlice in the underground and washing out the surface waterlice, water current velocity should be measured in the natural habitat of these populations

Accelerated Solvent Extraction of Phenols from Lyophilised Ground Grape Skins and Seeds

The efficient extraction of phenols from grapes is an important step for their reliable quantification. The aim was to optimise the lyophilisation process and the extraction of phenols from grape skins and seeds. The phenol extraction yield from lyophilised tissues was investigated with different accelerated solvent extraction (ASE) operating conditions. Skins and seeds were separated from frozen berries and lyophilised without being ground. The weight loss during lyophilisation was followed daily. Phenols were extracted from lyophilised, cryo-ground seeds and skins with ASE at room temperature and 10.3 MPa using 80% aqueous acetone and 60% aqueous methanol. The effects of ASE operational parameters (the number of extraction cycles (ECs) and static time (ST) duration) were investigated. The yield of extracted phenols was evaluated spectrophotometrically by determining total phenolic index at 280 nm (TPI). The weight of skins and seeds significantly dropped after 24 h of lyophilisation and continued to decrease, although not significantly, up until the 9th day. The optimal lyophilisation time was estimated to be 3 days and 5 days for skins and seeds, respectively. The phenol extraction yield was significantly affected after changes of ASE conditions. Based on TPI, the optimal ASE conditions were as follows: (i) lyophilised seeds—eight ECs with 10 min ST using aqueous acetone and then four ECs with 20 min ST using aqueous methanol; (ii) lyophilised skins—eight ECs with 1 min ST using aqueous acetone and then one EC with 20 min ST using aqueous methanol

An investigation of vine water status as a major factor in the quality of Merlot wine produced in terraced and non-terraced vineyards in the Vipava Valley, Slovenia

Terraced vineyards are cultural landscapes with a special value. The increase in costs and the lack of professional workers make viticulture on terraces difficult to be maintained. Thus, in the face of climate change and production challenges, we aimed to study the impact of slope-wise cultivation on wine quality. The quality of Merlot wines from terraced and slightly lower non-terraced vineyards within a small area characterised by similar mesoclimatic features was compared in the seasons 2019 and 2020. The non-terraced and terraced vineyards differed in both soil profile and morphology. The number of buds, number of clusters, and leaf area were standardised, and the stem water potential (SWP) was measured during wine-growing seasons. Upon reaching maturity, grapes were hand-picked on the same day in all vineyards and microvinified. The wines were analysed chemically and sensorially. In both years, the SWP showed higher water stress in the vines from terraces. The yield, berry weight, and leaf area were lower on terraced than on non-terraced vineyards in both years, and the skin- and seed-to-flesh ratios were higher. The darker seed colour pointed to the advanced ripening on terraces, where the wines had a higher alcohol concentration and a higher total dry extract. The wines from terraces had higher concentrations of total polyphenols, anthocyanins, and proanthocyanidins (PAs) than the wines from non-terraced vineyards in both years, and the PAs in the wines from terraces in 2019 had fewer prodelphinidins and were more galloylated. Higher concentrations of higher alcohols and lower concentrations of esters and methoxypyrazines were found in the wines from terraces. The sensory analysis revealed a preference for wines from terraces with better colour intensity, fruitiness, astringency, midpalate, and overall quality. Under experimental conditions (the same harvest date, standardised viticultural variables), the wines from terraces had both better phenolic potential and better sensory quality than the wines from non-terraced vineyards

High spatial heterogeneity of water stress levels in Refošk grapevines cultivated in Classical Karst

Grapevines are being challenged by climate changes, forcing winemakers to implement irrigation systems to cope with excessive water stress. Previous studies focused on a small set of international varieties, and only few data are available for terroirs hosting cultivars with possibly different responses to drought stress. In this light, we monitored grapevine water status and grape’s physical and chemical composition, as well as concentration and structural characteristics of grape extractable polyphenols, in ten different Refošk vineyards located in the Classical Karst terroir during 2018 and 2019. Grapevines did not suffer severe stress during the two years, but their response to water shortage periods was highly heterogeneous, as pre-dawn (Ψpd) and minimum (Ψmin) leaf water potential significantly differed between vineyards, especially during the drier part of the season. Moreover, the timing of maximum water stress differed in the two years, as in 2019 longer water shortage periods and higher temperature occurred at flowering stage and before veraison, while in 2018 they were higher after veraison. These differences influenced berry’s quality, as titratable and malic acid concentration in juice, as well as total anthocyanin, total polyphenols and higher high molecular weight proanthocyanidins (HMWP) concentration in skins, were higher in 2019 than in 2018. Regarding seed proanthocyanidins, HMWP concentration, mean degree of polymerisation (mDP) and percentage of galloylation (G) in seeds were higher in 2018 than in 2019. The differences in water status measured in spatially close-related vineyards strongly support the importance of monitoring grapevines’ water status dynamics to design adequate and effective water management activities rather than relying on climate data solely. Moreover, the timing of water shortage periods also played a role in determining Refošk grape quality. Our analyses showed that the higher (but still moderate, with Ψpd and Ψmin mean values around −0.50 and −1.25 MPa, respectively) water stress between veraison and harvest occurred in 2018 might reduce Refošk grape acidity and increase concentration, polymerisation and galloylation of seed extractable proanthocyanidins