43 research outputs found
Analysis of Climate Elements in Central and Western Istria for the Purpose of Determining Irrigation Requirements of Agricultural Crops
A consequence of climate changes is an increasing frequency of drought, which on average
occurs in Croatia every third to fifth year and during the vegetation period it can reduce crop
yield significantly. The aim of the research is both to determine crop water requirements in
an average and in a dry year and to determine the decline in crop yields in an average and in
a dry year. The multi-annual climate data series for a 30-year period, 1981-2010 from station
Pazin in central Istria and 1981-2010 from PoreÄ in western Istria was used. Based on these
data, a reference evapotranspiration was calculated for an average and a dry year using the
Penman-Monteith method through "Cropwat" software. The crop water requirement for five
different crops is determined by soil water balance using the Palmer method (Palmer, 1965),
corrected according to Å iriÄ and VidaÄek (1988), using "Hidrokalk" software. Crop response
to the lack of soil water and yield decline were determined according to the method published
by Doorenbos and Kassam (1979). Correlation test was used to determine correlation
between precipitation and crop yields. In central Istria, water shortage in an average year
ranged from 3.4 mm (olives) to 110.7 mm (alfalfa) and yield decline ranged from 1.1%
(olives) to 18.6% (alfalfa), while in a dry year water shortage ranged from 43.2 mm (olives)
to 229.5 mm (alfalfa) and ranged from 10.3% (olives) to 37.7% (alfalfa). In western Istria, in
an average year water shortage ranged from 35.5 mm (olives) to 239.7 mm (alfalfa) and yield
decline ranged from 7% (olives) to 40.2% (tomatoes), and in a dry year water shortage ranged
from 74.4 mm (olives) to 288.9 mm (alfalfa) and yield decline ranged from 14.4% (olives) to
40.7% (alfalfa). The determined water shortage and reduced yields are sufficient indicators of
irrigation requirements in Istria
Mehanizmi toksiÄnosti ionskih kapljevina
Over the past three decades a growing awareness of environmental protection prompted the development of so-called green and sustainable technologies. Therefore, academic and wider community intensively explores new chemicals and safer, more energy efficient processes based on a rational compromise between economic, social, and environmental requirements. Due to low volatility and stability, ionic liquids emerged as a potential replacement for traditional volatile and harmful organic solvents. Various studies have been carried out to validate the green character of ionic liquids, whereby data published suggest that these compounds, due to their relatively high toxicity and poor biodegradability, could have an extremely negative impact on the environment. This paper presents the current knowledge on the toxicity of ionic liquids, with a special emphasis on the mechanisms by which this group of compounds causes changes in the morphology and physiology of organisms at different organisational levels of the ecosystem.U protekla tri desetljeÄa sve viÅ”e raste svijest ljudi o potrebi zaÅ”tite okoliÅ”a, pa se velika pozornost pridaje tzv. zelenim i održivim tehnologijama. Stoga se u akademskim sredinama, a i u Å”iroj zajednici, intenzivno istražuju nove kemikalije te sigurniji i energetski uÄinkovitiji procesi koji se zasnivaju na prihvatljivom kompromisu izmeÄu ekonomskih, socijalnih i ekoloÅ”kih zahtjeva. Ionske se kapljevine zbog neznatne hlapljivosti i stabilnosti smatraju potencijalnom zelenom zamjenom za tradicionalna i Å”kodljiva organska otapala. Kako bi se potvrdio zeleni karakter ionskih kapljevina, posljednjih godina provode se razliÄita istraživanja njihova uÄinka na okoliÅ”. Do sada objavljeni podaci upuÄuju na to da bi ova skupina spojeva, zbog relativno visoke toksiÄnosti i slabe biorazgradljivosti, ipak mogla imati izrazito negativan utjecaj na okoliÅ”. U ovom radu prikazana su dosadaÅ”nja saznanja o toksiÄnosti ionskih kapljevina, s naglaskom na mehanizme kojima ova skupina spojeva uzrokuje promjene u morfologiji i fiziologiji organizama koji se nalaze na razliÄitim organizacijskim razinama ekosustava
Primjena kultura stanica za odreÄivanje bioloÅ”ke aktivnosti spojeva iz biljaka
Prirodni proizvodi poput žitarica, oraÅ”astih plodova, voÄa, povrÄa i ljekovitog bilja sadrže brojne bioloÅ”ki aktivne tvari (fenolne spojeve, glukozinolate, karotenoide, alkaloide i dr.) koje mogu imati razliÄite povoljne, ali i nepovoljne uÄinke na organizam. Povoljni uÄinci na zdravlje ljudi povezuju se s antitumorskim, antialergijskim, antibiotiÄkim, antioksidacijskim i drugim svojstvima koje mogu posjedovati bioloÅ”ki aktivne tvari iz biljaka. UtvrÄeno je da djelovanje navedenih tvari ima zaÅ”titni uÄinak kod Å”irokog raspona tumorskih oboljenja, smanjuje moguÄnost pojave koronarnih bolesti, srÄanog udara te Å”titi organizam od oksidativnog stresa uzrokovanog slobodnim radikalima. Stoga se sve viÅ”e ispituje primjena bioloÅ”ki aktivnih tvari iz biljaka kao izvora novih lijekova, pri Äemu se u istraživanjima Äesto koriste in vitro testovi koji ukljuÄuju uporabu razliÄitih humanih staniÄnih linija.
StaniÄne linije koriste se u procjeni toksiÄnosti kemikalija i uzoraka iz okoliÅ”a te predstavljaju vrlo koristan alternativni pristup u (eko)toksikoloÅ”kim istraživanjima. TakoÄer, Äesto se koriste pri ispitivanju bioloÅ”ke aktivnosti spojeva prisutnih u biljkama, osobito voÄu i povrÄu, te raznih proizvoda koji se baziraju na tim sirovinama. Interakcija ispitivane tvari i bioloÅ”kih sustava odvija se ponaprije na staniÄnoj razini, na Äemu se temelji primjena in vitro staniÄnih kultura, koje omoguÄuju brže i ekonomiÄnije studije u odnosu na in vivo istraživanja. Kod in vitro testova najÄeÅ”Äe se odreÄuje tzv. bazalna citotoksiÄnost, kojom se odreÄuje uÄinak ispitivane tvari na preživljenje stanica u kulturi, a tako dobiveni rezultati mogu poslužiti kao smjernice za daljnja in vivo istraživanja
Glucosinolates potential role in plant defence
Glukozinolati su složena klasa spojeva tioglukozidne strukture svojstvena biljkama porodice Cruciferae, u koju ubrajamo znaÄajne kulture kao Å”to su uljana repica, kupus, cvjetaÄa, brokula, koraba, kelj, hren, goruÅ”ica. Sve biljke koje sadrže glukozinolate sadrže i endogeni enzim hidrolize - mirozinazu (Ī²-tioglukozid-glukohidrolaza, EC 3.2.1.1) u odijeljenim dijelovima biljke. OÅ”teÄenjem tkiva oni dolaze u kontakt s enzimom mirozinazom te ovisno o strukturi glukozinolata nastaju razliÄiti bioloÅ”ki aktivni produkti razgradnje, koji imaju Äitav niz bioloÅ”kih svojstava, od toksiÄnih do antikarcinogenih. Udio i sastav glukozinolata razlikuje se izmeÄu biljnih vrsta te izmedu sorata istih vrsta te se mogu razlikovati unutar biljne jedinke ovisno o stupnju razvoja i vrsti organa. RazliÄiti uvjeti okoliÅ”a u kojima se biljka nalazi, kao Å”to su svjetlo, nutritivni status biljke, mehaniÄko oÅ”teÄenje, infekcija fitopatogenima i oÅ”teÄenja uzrokovana napadom insekata, mogu uzrokovati znaÄajne promjene u sastavu i udjelu glukozinolata. Stoga postoji niz teorija o potencijalonoj ulozi glukozinolata u biljci, iako se njihova uloga u obrani biljke od insekata i fitopatogena smatra primarnom.Glucosinolates are sulfur- and nitrogen-containing plant secondary metabolites common in the Brassicaceae and related plant families. In the plant, they coexist with an endogenous Ī²-thioglucosidase (EC 3.2.3.1) called myrosinase and upon plant tissue disruption, glucosinolates are released at the damage site and become hydrolyzed by myrosinase. The chemical nature of the hydrolysis products depends on the structure of the glucosinolate side chain, plant species and reaction conditions. Glucosinolate pattern differs between species and ecotype as well as between and even within individual plants, depending on developmental stage, tissue and photoperiod. A number of environmental conditions such as light plant, nutritional status, fungal infection, wounding and insect damage can alter the glucosinolate pattern significantly. The change of the glucosinolate profile by several environmental factors has brought forward different theories regarding their potential roles in the plant. However, the most accepted theory is that the glucosinolate-myrosinase system is involved in defense against herbivores and pathogens
Bioactive compounds glucosinolates and polyphenols in florets, leaves and stems of broccoli (BrassicaĀ oleracea var. italica L.)
Brokula (Brassica oleracea var. italica L.) je povrÄe koje se smatra izvornim oblikom cvjetaÄe, a uzgaja se zbog zelenih cvjetnih izdanaka smjeÅ”tenih na razgranatoj mekanoj stabljici. Brokula je bogata bioaktivnim spojevima, glukozinolatima i polifenolima te se uvelike istražuje radi njihova korisnog djelovanja na ljudsko zdravlje. U literaturi je mnogo viÅ”e radova o sastavu i udjelima bioaktivnih spojeva u cvatu nego u listovima i stabljici biljke. U ovom radu analizirani su ukupni i pojedinaÄni glukozinolati, ukupni polifenolni spojevi te njihov antioksidacijski kapacitet u svim jestivim dijelovima brokule (cvat, listovi, stabiljka). UtvrÄeno je da je koliÄina glukozinolata najveÄa u listu brokule pri Äemu udio indolnih prevladava nad alifatskim spojevima Å”to vrijedi i za cvat. U stabljici je veÄi udio alifatskih spojeva. Udio polifenolnih spojeva u uzorcima u rasponu je od 9,70-16,11 mg GE g-1 s. tv. u stabljici, od 17,65-31,08 mg GE g-1 s. tv. u cvatu i od 22,27-34,02 mg GE g-1 s.tv. u listu brokule. VeÄu antioksidacijsku aktivnost pokazuju uzorci s veÄom koncentracijom polifenola. Ti rezultati upuÄuju da ne samo cvat brokule veÄ i ostali dijelovi biljke mogu biti vrijedan izvor bioaktivnih spojeva te ih se preporuÄa takoÄer koristiti u prehrani. Nadalje, nusproizvodi nakon berbe, stabiljke i listovi mogli bi se koristiti kao sirovina za njihovu izolaciju te eventualnu uporabu kao dodataka prehrani.Broccoli is rich in bioactive compounds, polyphenols and glucosinolates, and as such considered as functional food and great experimental material. Previous scientific attention had mostly been focussed on composition and amounts of phytochemicals in florets rather than leaves and stem. In this research, content of total and individual glucosinolates, total polyphenols and antioxidative capacity were studied in broccoli florets, leaves and stems. Leaves showed to be the most abundant in glucosinolates with indolyl predominating aliphatic as was also the case in florets. In contrast, stem contained more aliphatic than indolyl glucosinolates. Polyphenol quantity ranged from 9.70-16.11 mg GE g-1 DW in stems, from 17.65-31.08 mg GE g-1 DW in florets and from 22.27-34.02 mg GE g-1 DW in leaves and was the highest in leaves irrespective of extraction method. It was determined that samples containing the highest amounts of polyphenols also had the highest antioxidant activity