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Actual state of research concerning vitamin C as reflected in the literature (Review article)
7-15.Views:754Vitamin C (L-ascorbic acid) being essential for many living organisms, including man, became once more into the focus of interests because of its numerous physiological effects. Its anti-scurvy and anti-oxidant properties have already been recognised since long in the human body, but it turned out gradually that it has many other functions. In plants, its primary importance is defense against the photo-oxidative stress.
The present review is intended to reveal some details of the artificial synthesis of vitamin C. Emphasis is put on the metabolism of L-ascorbic acid in higher plants. Biosynthetic processes, translocation and accumulation are discussed in detail on the basis of recent results published in the scientific literature.
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Temporal changes of the frequency of spring frost damages in the main fruit growing regions in Western Hungary and in East Hungary
81-87.Views:1261Most of the risk in Hungarian fruit growing is the damage caused by late spring frosts. The frequency of late frosts seems to increase nowadays. The aim of the study was to check this contention: what is the real probability of the damages. Based on earlier experiences, the physiological LT50 function has been elaborated for new fruit varieties, which are eligible to moderate the danger when being threatened by frost. By means of this technique, the probability of freezing is distinguished between frost susceptible, frost resistant and medium frost resistant fruit species and varieties around their blooming time. The degree of frost damage depends on the duration and severity of the low temperature and not at least on the frost tolerance of the plant. For that purpose, the frequencies of frost damages were studied at two Transdanubian and two Trans-Tisza fruit growing sites by means of a meteorological database for the 60-year-long period 1951–2010. Being aware of the LT50 values changing during the phonological phases of the fruit trees from budding, bloom, fruit set and fruit growth, the number and date of critical (frosty) days could be settled. An important role is attributed to the orographic relief and the height above the sea level of the site, as 20–30 m differences and expositions may become decisive within the same plantation. The spatial distribution of damages is also dependent on the air circulations within the Carpathian basin. At the southern and northern borders of the country, especially valley bottoms represent additional risks of frost. Most spring frost damages are experienced in April 20–22, and cause heavy damages by temperature minima between – 3°C and – 6°C. The severity of damage depends largely on the temperature of the preceding few days. The earlier bloom the heavier damage is expected. The study is emphasising the importance of the varieties. Frost tolerance of some varieties may lower the risk of spring frosts by 40–50%, as experienced on the plantations. The quantifi cation of the risks based on data raised during the last years will be suitable to defi ne the security of yields of each growing site successfully.
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Fruit drop: II. Biological background of flower and fruit drop
103-108.Views:1184The most important components of fruit drop are: the rootstock, the combination of polliniser varieties, the conditions depending of nutrition, the extent and timing of the administration of fertilisers, the moments of water stress and the timing of agrotechnical interventions. Further adversities may appear as flushes of heat and drought, the rainy spring weather during the blooming period as well as the excessive hot, cool or windy weather impairing pollination, moreover, the appearance of diseases and pests all influence the fate of flowers of growing and become ripe fruits. As generally maintained, dry springs are causing severe fruit drop.
In analysing the endogenous and environmental causes of drop of the generative organs (flowers and fruits), the model of leaf abscission has been used, as a study of the excised, well defined abscission zone (AZ) seemed to be an adequate approach to the question. Comparing the effects active in the abscission of fruit with those of the excised leaf stem differences are observed as well as analogies between the anatomy and the accumulation of ethylene in the respective abscission tissues.
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Interaction of nutrient supply and crop load of apple trees (Malus domestica Borkh.)
33-35.Views:341Long term fertilisation trials were combined with storage experiments with 'Jonathan' apple trees and fruits to study influence of tree nutrition on quantity and quality of crop. The site of experiments is a typical Carpathian-basin environment with loamy silt soil, high lime content and arid summers. Conclusions has been drown from six years' set of data. Augmented levels of soil fertilisation increased cropping capacity of apple trees, however, the fruit load has not met with cropping capacity in every year. More the def cit came into view in crop load, less the fruit quality resulted in. The deficit in cropping capacity, however, could not have been determined with simple rates as fruit weight per trunk circumference or similar. Better determination was obtained where foliar nutrient contents were correlated to crop per tree figures. In general terms, the N and Ca content in leaves increased with yields when K and P content formulated reciprocally. When storage quality of 'Jonathan' apple fruits were related to crop load (kg/tree), influence of crop deficit became visible. As the crop load and foliar nutrient levels interacted, the fruit quality (number of disordered apples after 6 month of storage) subjected of both physiological phenomena. Higher determination degree were obtained when crop load was assessed together with single or multiple foliar analysis data.
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Study on the Penicillin-content of botrytized wines and noble rotted berries in Tokaj-region
91-94.Views:456Favourable parameters are offered to the formation of noble rot caused by Botrytis cinerea by the climatic conditions, soil circumstances and grape-varietes of Tokaj-region. As the result of noble rot, aszú-berries represent the most important raw material of the world-wide known Tokaji Aszú Wine. The objective of this study was to measure the penicillin-content of aszú-berries and Tokaj Wine Specialities. As the result of infection of Botrytis free way can be opened in front of other mould strains, especially Penicillium and Aspergillus. There is a possibility to the presence of Penicillium chrysogenum on the surface of aszú-berries during noble rotting process. P. chrysogenum was found to produce the so called Naturally Derived Penicillins such as Penicillin-V (phenoximethyl-penicillin).
According to our findings the Penicillin-V content was detected between 0.4 and 26 mg/1 wine and 0-74 mg/kg aszú-berry. These values do net have therapeutic effect, but physiological benefit and it can be a basis to the qualification of the raw material of Tokaj Wine Specialities naturally together with the other component of noble rotted berries and botrytized wines.
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The effect of cluster thinning, cluster tipping, cluster shredding and defoliation at the flowering on the vegetative and generative vine performance from Kékfrankos Cv.
63-68.Views:519The cluster thinning is a method of the yield regulation.With the removal one part of the clusters, the yield pro leaf area will be lower, hereby the grape and wine quality will be improved. The regulation of the yield can lead to further advantages: the ratio of the vegetative and generative performance of the vines will improve, the condition of the plants will better, the number of the physiological diseases can be reduced and the growth of the shoots and roots can be promoted. The grape growers make the cluster thinning almost exclusive by creating one cluster shoots. Usually the upper clusters are removed, because the sugar content of these second or third clusters will be lower. The cluster thinning is an easy task, can be done without special skills. It is an effective method improving wine quality, but its use can lead to other problems. The grapes try to compensate the removed clusters. Therefore the clusters will be bigger and thicker, but more sensitive to bunch rot. Moreover the treatment is expensive, because it needs manual work. It is worth to get acquainted and try the new yield regulation methods, which can help to avoid the occurring problems. Our aim is to show the results of our experiment, which was carried out in Eger, examining the red grape cultivar Kékfrankos. During our 4 years long experiment we compared the effects of cluster thinning, cluster shredding, cluster tipping and defoliation at the flowering, on the vegetative and generative vine performance.
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Treatments for improving tree growth, yield and fruit quality and for reducing double fruit and deep suture incidence in “Desert red” peach trees
7-19.Views:578Five years old “Desert red” peach trees budded on Nemaguard rootstock and grown in sandy soil at commercial orchard Al-Nubaria city, El-Behira Governorate-Egypt were treated with some agricultural treatments involving thinning out pruning, fruit thinning and foliar application of potassium silicate (25% S +10% K2O) at 0.1% and super grow (20% N, 20% P2O5 and 20% K2O) at 0.3% in 2014 and 2015 seasons, to study their effects on yield and fruit quality and the relationship between nutrient balance and yield of “Desert red” peach trees. Beside, testing the influence of used treatments on two physiological disorder, double fruit and deep suture %. Also, economic evaluation of different treatments was done. All obtained data were statistically analyzed using a randomized complete block design. Depending on the obtained results in this study, it could be concluded that application of thinning out pruning 35%, fruit thinning by leaving 15 cm between fruits on one-year old shoot at 20 days after full bloom and foliar application of potassium silicate which sprayed five times during each growing season at fruit set, the second fruit development stage, the beginning of the fruit color change and twice after month from harvest, most profitable treatment for peach trees grown under conditions of this investigation. This treatment gave the best vegetative growth, yield, fruit quality, higher crop value with high net income /fed. from “Desert red” peach trees, in addition, reduced the percentage of double fruit and deep suture by more than 50% in both seasons, therefore, the study recommends this treatment for “Desert red” peach growers.
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Transmethylation and the general defense reaction of plants
35-40.Views:406Plant breeding for resistance, namely building specific resistance genes into cultivated plants to ensure resistance against certain pathogen species, is a several-decade-long practice. While looking for purposes of failures appearing during the cultivation of varieties created in this way, a plant feature that ensures non-specific reactions against effects which evoke biotic stress attracted our attention. We named this plant defense form the general defense reaction. The general defense reaction is a fundamental attribute of the plant kingdom, fulfils the role of plant immune system and manifests itself in cell enlargement and cell division. Plants with a high level general defense reaction endure abiotic stresses as well.
In studying the biochemical background of the interaction of the general defense reaction and transmethylation, we found that transmethylation has important role in warding off both biotic and abiotic stresses. According to our observations, plants possessing high level general defense system are suitable for thorough examination of the process and plant physiological role of transmethylation. Biochemical studies also strengthened our observation, which has been taken on the basis of phenotype, that the general defense system can not be ignored during future plant breeding.
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Impact of sodium-selenate on the growth of radish (Raphanus sativus L.) seedlings in vitro
113-115.Views:704Selenium (Se) is an essential trace element for animals, microorganisms and some other Eukaryotes. It has become increasingly evident that Se plays a significant role in reducing the incidence of lung, colorectal and prostate cancer in humans. Although it is well known that some species among higher plants are able to accumulate selenium in their tissues, but others are not able to do so, and there is evidence that selenium is needed for the growth of algae, meanwhile the question of essentiality of Se in vascular plants is unresolved. We aimed to study the in vitro growing and to characterise some physiological properties in radish (Raphanus sativus L.) seedlings treated with 0 to 200 mg/1 sodium-selenate. The results showed that lower (2 mg/1) concentration sodium-selenate increased the biomass as well as the total antioxidant capacity of seedlings. The seedling's selenium content showed linear correlation with the sodium-selenate content of the medium.
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Evaluation of morphological parameters and bioactive compounds in different varieties of beetroot (Beta vulgaris L. ssp. esculenta GURKE var. rubra L.)
31-35.Views:881Beetroot consumption based on pickled beets generally in Hungary which is due to the higher yield from second crop harvested in autumn and processed by manufacturing industry. Researches of the past years confirmed its favourable nutritional-physiological effects on human body so demands, as for fresh salad, also increased. The trial aimed at testing the interaction of varieties on quality parameters and in the same time suggestions are made how to use different varieties of beetroot according to its quality. Morphological and sensory evaluations were examined on 10 varieties of beetroot harvested in autumn. The regular spherical shape can reduce the refining loss during the processing of beetroot which is beneficial for the manufacturing industry. In our trial the root shape of Libero, Mona Lisa and Rubin varieties approached most the regular spherical shape (diameter/length – 1.0) which is favoured by not only processing industry but also fresh market. The highest red pigment content (betanin) was observed in Mona Lisa, Akela and Cylindra (34.58–47.66 mg/100 g). A similar trend could be observed in yellow pigments (vulgaxanthins) which proves the close correlation between the quantities of the two pigments (r=0.898). Highest total polyphenol (77.13–83.37 mg GAE/100g) and flavonoid (21.73–22.73 mg CE/100g) contents were detected in Akela, Mona Lisa and Bonel. These varieties are favourable for fresh salad and they can satisfy processing requirements also. Highest water soluble solids content was found in Akela (7.15%). In our conditions nitrate (NO3-N) values below 900 mg/kg were examined in all of the varieties which is favourable in the case of beetroot.
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Water relations of sour cherries (minireview)
103-107.Views:430Recently, the sour cherries as food resources become more important for health preservation and so the modernization of growing technology in sour cherry production will be timely. The global warming and inadequate distribution of precipitation result a decrease in the alternancy of sour cherry production, as well. Sour cherries rather adapted to survival of drought than sweet cherry trees therefore a few studies performed to explore the water requirement of sour cherry varieties. The rootstocks, the type of soils in plantation and the water balance influence the water management of sour cherries. In orchards, in particular first year plantation, use of various row covering contribute to preservation of the natural water pool of soil and affect on the tree vigor, yield and fruit quality. Wide-spread application of integrated fruit growing technology and climate changes the researches are pointed to develop efficient irrigation technology based on transpiration yield model. The crop model based on use of meteorological data was developed for cherry orchards in order to predict transpiration of trees, dry matter production and fruit yield. The linear relationship between dry matter accumulation and transpiration was verified for sour cherry trees. Other models essay to asses the effects of climate changes on crop production. Importance of economical production and fruit quality such as ingredients of raw materials and food increases in intensive sour cherry orchards used by irrigation techniques. Because of climate changes it should more pay attention to research concerning on the stress physiological response of sour cherry varieties and post-harvest fruit quality.
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New trends in selection of poppy (Papaver somniferum L.)
69-75.Views:595Since the isolation of morphine by Sertümer in 1805 more than 40 alkaloids have been isolated from the poppy (Papaver somniferum L.). Some of them have high biological-pharmacological activity and economical importance, while others have none, or restricted ones. The increasing demand for poppy alkaloids is the consequence of the widening of the medical application of morphine and its related compounds: the quantity of morphine used for the treatment of pain reached a record level of 17.9 tonnes in 1997, compared with an annual average of 2.2 tonnes used during the period 1978-1983. However, the production of raw material (either opium, or dried capsule is produced) has to be re-evaluated taking into consideration the UN Convention signed in 1988 against Illicit Traffic in Narcotic Drugs and Psychotropic Substances. The countries were forced by the Convention to introduce new arrangements in poppy production including selection and introduction of new cultivars.
In the present work up to date results of poppy selection are reviewed explaining the biosynthetic and eco-physiological background of their alkaloid accumulation. The effectiveness and the possibilities of traditional selection methods as well as the probability of the application of biotransformation for producing cultivars accumulating low or high alkaloid content or plant material with special alkaloid spectrum (codeine, thebaine, narcotine) are discussed. The examples of Hungarian cultivars 'Monaco', 'Kék Gemona' and 'Tebona' are given in more detail.
