Sterilizacija različitih tipova eksplantata u mikropropagaciji podloga trešnje CAB-6p i Gisela 6

Research with the objective of finding efficient (non residual) sterilants for the purpose of greater automatization in establishing aseptic in vitro tissue culture was conducted on cherry rootstocks CAB 6P and Gisela 6. Two ways of sterilization were examined (NaOCl and ozone O3) through survival rate on three types of explants; buds with primordial leaves, buds without primordial leaves and nodal non lignified segment with axillary buds. Ozone resulted with the high rate of survival (from 57 to 93%) regardless of the type of explants and the rootstock variety. By introducing a complete bud without destruction significantly resulted with the higher rate of survival (from 90 to 97%). Results indicate the potential for ozone sterilization of the starting material not only as an ostensible but the perforated (sub-cuticular transpiration) agent.Istraživanja s ciljem pronalaženja učinkovitih sterilizanata, u svrhu veće automatizacije u uspostavi aseptične kulture tkiva in vitro, provedena su na podlogama trešnje CAB 6P i Gisela 6. Ispitivana su dva načina sterilizacije (NaOCl i ozon O3), prateći stopu preživljavanja na tri tipa eksplantata; pupovi s primordijalnim lišćem, pupovi bez primordijalnoga lišća i nodijalni nelignificirani segment s aksilarnim pupom. Ozon je rezultirao visokom stopom preživljavanja (od 57 do 93%), bez obzira na vrstu eksplantata i varijante podloge. Uvođenjem cjelovitoga pupa bez destrukcije značajno je rezultiralo višom stopom preživljavanja (od 90 do 97%). Rezultati ukazuju na potencijal sterilizacije ozonom inicijalnoga biljnoga materijala, ne samo kao površinskoga, nego i penetrirajućeg (subkutikularnog) agenta

UTJECAJ EKOLOŠKI PRIHVATLJIVIH TRETMANA NA ANTIOKSIDACIJSKU AKTIVNOST U PLODOVIMA JAGODA TIJEKOM SKLADIŠTENJA

Proper postharvest storage is an effective way to maintain the quality and nutritional values of fruits. The aim of this study was to determine how environmentally friendly postharvest treatments with salicylic acid solution, colloidal silver solution and ozone, affect the antioxidant activity of strawberry fruits (Fragaria x ananassa Duch. cv. Albion) during 7 days of storage at 4°C. The content of ascorbic acid, total phenols and antioxidant activity of strawberry fruits were determined spec-trophotometrically. After 7 days of storage in strawberry fruits treated with all three treatments separately, the contents of ascorbic acid were higher than in the control fruits, supporting the usefulness of these treatments for preserving fruit quality and nutritional value during storage. The treatment with salicylic acid solution showed the most beneficial effect during storage causing a significant increase in the content of ascorbic acid, phenols and antioxidant activity at the end of the storage period.Pravilno skladištenje voća učinkovit je način za održavanje kvalitete i nutritivne vrijednosti plodova nakon berbe. Cilj ovog istraživanja bio je utvrditi kako ekološki prihvatljivi tretmani (otopina salicilne kiseline, otopina koloidnoga srebra i ozon) utječu na ukupnu antioksidacijsku aktivnost u plodovima jagoda (Fragaria x ananassa Duch.) sorte Albion tijekom 7 dana skladištenja pri 4°C. Koncentracije askorbinske kiseline, ukupnih fenola i ukupna antioksidacijska aktivnost u plodovima jagoda određeni su spektrofotometrijski. Svi primijenjeni tretmani prouzročili su povećanje koncentracije askorbinske kiseline u plodovima jagoda, što potvrđuje povoljno djelovanje navedenih tretmana na očuvanje kvalitete i nutritivne vrijednosti plodova. Tretman otopinom salicilne kiseline bio je najučinkovitiji, jer je prouzročio značajno povećanje koncentracije fenola, askorbinske kiseline i ukupne antioksidacijske aktivnosti na kraju perioda skladištenja

Changes in Photosystem II Photochemistry in Senescing Maple Leaves

Biochemical and functional changes in photosystem II (PSII) were investigated during natural senescence of maple (Acer platanoides L.) leaves. Three different types of senescing leaves were used: early senescent green (G), yellow green (YG) and yellow (Y). The main goal of this study was to investigate the dynamics of degradation of major photosynthetic proteins (D1, LHCII and Rubisco LSU) and how this would reflect on PSII photochemistry. It was revealed that D1 and LSU degrade faster than LHCII. Such differential degradation dynamics influenced PSII photochemistry. A decrease in the maximum (Fv/Fm) and effective (ΔF/F\u27m) quantum yields of PSII as well as a decrease in its capability for O2 evolution were observed. Analysis of chlorophyll a fluorescence transient measurement (OJIP test) in senescent leaves showed striking decrease in performance index (PIABS), a measure of overall photosynthetic performance. Further, increased absorption, trapping and dissipation of excitation energy per reaction centre were found in senescent leaves. In addition, it was shown that a marked decrease in electron transport beyond the primary electron acceptor (QA) in Y leaves was due to reduced electron transfer ability from QA– to QB. It can be concluded that molecular and functional modifications of a certain fraction of reaction centres from active to dissipative might be considered an important regulatory mechanism in chloroplast electron-transport chain redox poise control during natural senescence of maple leaves

Selenium biofortification

Selen (Se) je mikronutrijent koji se u prirodi pojavljuje u tragovima, ali u brojnim organskim i anorganskim oblicima. Primijenjen u odgovarajućim koncentracijama ima brojne pozitivne učinke na organizme, dok izloženost prekomjernim koncentracijama Se vodi ka toksičnosti i oksidacijskom stresu. Količina Se koja se dnevno unosi prehranom odraz je zastupljenosti elementa u tlu. Na svjetskoj razini prevladavajući je udio područja siromašnih Se, stoga se pojavljuje i velik broj oboljelih od malnutricije. Obećavajuće rješenje problema je biofortifikacija usjeva, ponajprije pšenice, jedne od najzastupljnijih žitarica u prehrani ljudi. Biofortifikacija usjeva poboljšava kvalitetu prehrambenih proizvoda uslijed povećanja koncentracije bioraspoloživog Se, a na područjima siromašnim Se najčešći izbor je agronomska biofortifikacija.Selenium (Se) is a micronutrient that occurs in trace amounts but numerous organic and inorganic forms. Applied in appropriate concentrations, it has numerous positive effects on the living organisms, while exposure to excessive concentrations of Se leads to toxicity and oxidative stress. The amount of Se that is ingested daily through food reflects the presence of the element in soil. Globally, the share of low Se areas is predominant, and consequently, many malnutrition patients also occur. A promising solution to the problem is the biofortification of crops, primarily wheat, one of the main cereals in human nutrition. Crop biofortification improves the quality of food products due to the increase in the concentration of bioavailable Se, and in low Se areas, the most common choice is agronomic biofortification

Changes in Peroxidase Activity in the Peel of Unshiub Mandarin (Citrus unshiu Marc.) Fruit with Different Storage Treatments

The Unshiu mandarin (Citrus unshiu Marc.) is the major Citrus crop in Croatia. Limiting factors for longer consumption of Unshiu mandarin are low storage performance and the appearance of chilling injuries during storage. Previous studies indicated that oxidative stress might be involved in cold-induced peel damage of harvested Citrus fruit. The aim of the present study was to investigate peroxidase distribution, isoenzyme pattern and activity in the peel of Unshiu mandarin fruit. Special goal of our study was to investigate the changes of peroxidase activity in respect to two different hot water dipping (HWD) treatments (3 min at 48 and 52 °C) and two different storage temperatures (1 and 3 °C) combined. Peroxidase activity was detected at the border of oil glands, in the peel surface and in the conducting elements positioned in the inner part of the peel. Electrophoretic analysis revealed the presence of two peroxidase isoenzymes. There were no differences in the electrophoretic pattern after the HWD treatments and cold storage. Lowering of both total and specific peroxidase activity was measured in HWD-treated samples in comparison with the control ones. However, it appeared that significant decrease in total peroxidase activity was influenced by the storage temperatures, while the increase in total soluble protein content was influenced by the HWD pretreatment

Changes in Photosystem II Photochemistry in Senescing Maple Leaves

Biochemical and functional changes in photosystem II (PSII) were investigated during natural senescence of maple (Acer platanoides L.) leaves. Three different types of senescing leaves were used: early senescent green (G), yellow green (YG) and yellow (Y). The main goal of this study was to investigate the dynamics of degradation of major photosynthetic proteins (D1, LHCII and Rubisco LSU) and how this would reflect on PSII photochemistry. It was revealed that D1 and LSU degrade faster than LHCII. Such differential degradation dynamics influenced PSII photochemistry. A decrease in the maximum (Fv/Fm) and effective (ΔF/F\u27m) quantum yields of PSII as well as a decrease in its capability for O2 evolution were observed. Analysis of chlorophyll a fluorescence transient measurement (OJIP test) in senescent leaves showed striking decrease in performance index (PIABS), a measure of overall photosynthetic performance. Further, increased absorption, trapping and dissipation of excitation energy per reaction centre were found in senescent leaves. In addition, it was shown that a marked decrease in electron transport beyond the primary electron acceptor (QA) in Y leaves was due to reduced electron transfer ability from QA– to QB. It can be concluded that molecular and functional modifications of a certain fraction of reaction centres from active to dissipative might be considered an important regulatory mechanism in chloroplast electron-transport chain redox poise control during natural senescence of maple leaves

Comparative Study of Leaf Anatomy and Certain Biochemical Traits in Two Olive Cultivars

Olive (Olea europea L.) is one of the most cultivated trees in Dalmatia (Croatia). The aim of this work was to compare leaf anatomy, guaiacol peroxidases activity and soluble polyphenols content in two olive cultivars: Oblica and Leccino, to get preliminary data for further investigations of stress influence on their growth and productivity. Leaves from fi ve two–years–old trees of each, Olea europaea L. cv. Oblica and cv. Leccino were used in this study. Composed sample of each cultivar was used for determination of guaiacol peroxidases activity (GPOD), content of soluble polyphenols (PHEN) and dry weight (DW). The presence of lignin, suberin and callose were analyzed by histochemical reactions on fresh hand-made leaf sections. The leaf anatomy was studied on 3 μm thin sections stained with Toluidine blue O. There were significant differences of tissue areas between two olive cultivars. Bigger areas of upper and lower epidermis in cultivar Leccino leaves as well as bigger areas of schlerenchyma, idioblasts and intercellulars in leaves of cultivar Oblica were measured. Oblica had higher activity of GPOD and portion of DW than Leccino. Higher PHEN content was measured in Leccino leaves. Histochemical reactions showed more lignin and suberin in cultivar Oblica leaves. Based on the presented results, cultivars Oblica and Leccino should response differently on cold, salt and drought stress that should be the scope in further investigations

Comparative Study of Leaf Anatomy and Certain Biochemical Traits in Two Olive Cultivars

Olive (Olea europea L.) is one of the most cultivated trees in Dalmatia (Croatia). The aim of this work was to compare leaf anatomy, guaiacol peroxidases activity and soluble polyphenols content in two olive cultivars: Oblica and Leccino, to get preliminary data for further investigations of stress influence on their growth and productivity. Leaves from fi ve two–years–old trees of each, Olea europaea L. cv. Oblica and cv. Leccino were used in this study. Composed sample of each cultivar was used for determination of guaiacol peroxidases activity (GPOD), content of soluble polyphenols (PHEN) and dry weight (DW). The presence of lignin, suberin and callose were analyzed by histochemical reactions on fresh hand-made leaf sections. The leaf anatomy was studied on 3 μm thin sections stained with Toluidine blue O. There were significant differences of tissue areas between two olive cultivars. Bigger areas of upper and lower epidermis in cultivar Leccino leaves as well as bigger areas of schlerenchyma, idioblasts and intercellulars in leaves of cultivar Oblica were measured. Oblica had higher activity of GPOD and portion of DW than Leccino. Higher PHEN content was measured in Leccino leaves. Histochemical reactions showed more lignin and suberin in cultivar Oblica leaves. Based on the presented results, cultivars Oblica and Leccino should response differently on cold, salt and drought stress that should be the scope in further investigations

Fitokemijski sastav mljevene začinske paprike iz istočne Dunavske regije

This study aimed to evaluate the phytochemical composition of sweet and hot ground paprika originating from different production sites in the Eastern Danube Region, i.e. in Croatia, Serbia and Hungary. Obtained results showed that composition and level of metabolites as well as antioxidant activity in paprika samples varied greatly among different locations. For the first time, clear differences in the chemical composition of sweet and hot paprika obtained from two Hungarian wax pepper cultivars produced in three different states of the Eastern Danube region were determined. Averagely, paprika samples from Croatia had the highest carotenoid content but the lowest levels of phenols and flavonoids. The hot paprika samples from Croatia had the highest content of capsaicin and dihydrocapsaicin. Thus, the results of this investigation indicate that bioactive compounds in paprika can vary greatly depending on their geographical origin. However, this variation can also occur due to different production technology and processing methods. Further investigations and methods need to be employed to determine the factors responsible for variation of content of bioactive compounds in paprika.Cilj ovog istraživanja bio je utvrditi fitokemijski sastav slatke i ljute začinske paprike podrijetlom iz različitih uzgojnih područja u Istočnoj dunavskoj regiji, tj. u Hrvatskoj, Srbiji i Mađarskoj. Dobiveni rezultati pokazali su kako se sastav i razina metabolita, kao i antioksidacijska aktivnost, u uzorcima začinske paprike značajno razlikuju između različitih uzgojnih područja. Prvi su put istaknute jasne razlike u kemijskome sastavu slatkih i ljutih sorata mađarske paprike proizvedene u tri različite države Istočne dunavske regije. Općenito, uzorci paprike iz Hrvatske imali su najveći sadržaj karotenoida, ali najniže vrijednosti fenola i flavonoida. Uzorci ljute paprike iz Hrvatske imali su najveći sadržaj kapsaicina i dihidrokapsaicina, kao i najviše Scovilleovih jedinica ljutine. Stoga, ovo istraživanje ukazuje na prikladnost određenih uzgojnih područja za dobivanje paprike željenoga kemijskoga sastava. Podatci su vrlo zanimljivi i važni za prehrambeno prerađivačku i farmaceutsku industriju, kao i za usmjeravanje regionalnih proizvođača prema dobivanju kvalitetne mljevene paprike

ANTIOKSIDATIVNI ODGOVOR U LISTU JAGODA (Fragaria x ananassa Duch) NA TRETMANE BIOSTIMULATORIMA UZ REDUCIRANU GNOJIDBU DUŠIKOM I KALIJEM

Strawberry cultivar Elsanta was grown in peat based substrate in a green house. Full dose and 50% reduced nitrogen and potassium fertilization were applied during fruit bearing period in spring, along with biostimulators Viva®, Megafol® and their combination. The specific activities of guaiacol peroxidase (GPXs; EC 1.11.1.7), catalase (CATs; EC 1.11.1.6), ascorbate peroxidase (APXs; EC 1.11.1.11) and glutathione reductase (GRs; EC 1.6.4.2) in strawberry leaf were stimulated by biostimulators and reduced fertilization. The strongest link seen here was between the enzymes of ascorbate-glutathione cycle (APXs and GRs), which were positively related to trifoliate leaf fresh mass (TLFM). The highest TLFM was observed in Megafol® treated plants.Sorta jagoda Elsanta uzgajana je u tresetnom supstratu u plasteniku. Puna doza i 50% smanjena doza dušika i kalija primjenjene su tijekom proljetnoga plodonošenja, uz primjenu biostimulatora Viva®, Megafol® i njihove kombinacije. Specifične aktivnosti gvajakol peroksidaze (GPXs; EC 1.11.1.7), katalaze (CATs; EC 1.11.1.6), askorbat peroksidaze (APXs; EC 1.11.1.11) i glutation reduktaze (GRs; EC 1.6.4.2) u listu jagode bile su značajno više poslije tretiranja biostimulatorima i reduciranom gnojidbom. Najjača povezanost uočena u ovom istraživanju, bila je između enzima askorbat-glutation ciklusa (APXs i GRs), koji su bili u pozitivnoj korelaciji s masom svježega lista (TLFM). Najveća masa svježega lista (TLFM) uočena je na biljkama tretiranim Megafolom®