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Path analysis and correlation coefficient of environmental factors influencing foraging behaviour of four honeybee species pollinating litchi flowers (Litchi chinensis Sonn.)
77-82.Views:120Honeybee species Apis dorsata F; A. mellifera L; A. cerana F. and A.florea F. were the most important and efficient pollinators of litchi flowers (Litchi chinensis Sonn.) in India. They constituted more than 65% of the total pollinating insects. The ecological threshold for commencement and cessation of flight activity of each honeybee species varied from one another. In general, 15.5-18.5°C temperature, 600-1700 lx light intensity, 9-20 mW/cm2 solar radiation appeared to be the minimum ecological conditions for commencement of flight activity in Apis species. Cessation of activities in all the honeybee species was governed mainly by decline in values of light intensity and solar radiation irrespective of other factors.
In between commencement and cessation, the activity of all honeybee species followed the same general pattern as temperature (T), light intensity (LI). Solar radiation (SR). Nectar sugar concentration (NSC) and inversely with relative humidity (RH). Path analysis revealed that all the honeybee species differed in their responses to environmental factors prevailing under similar set of conditions depending upon physiological adaptation of each honeybee species. Of all the factors studied; temperature, light intensity and solar radiation were the three important factors whose influence on foraging population was more pronounced.
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Cracking susceptibility evaluation of some stone fruit species (Sour cherries – Prunus cerasus L.; Sweet cherries – Prunus avium and European plums – Prunus domestica L.) grown in Hungary
45-54.Views:250The rain induced fruit cracking is a big, serious problem especially for sweet cherry growers but in some year growers of other stone fruit species had also problem with fruit cracking caused by too much and heavy rainfalls in the ripening and harvesting season. Cracked stone fruits can be easily infected by different diseases like Monillinia sp. Cracked and infected fruits can not be transported for long distance and using for preservation, they lost their market value by the destroyed fruit quality. It was decided to make a research work to determine the rain fruit cracking susceptibility of few stone fruit species (sour cherries, sweet cherries and European plums). Fruit cracking tests were occurred under laboratory conditions on the most common cultivars grown in Hungary. Furthermore we tried to find correlation between the fruit cracking and some fruit quality parameters (fruit size; total sugar content, fruit flesh firmness).
Our conclusions are the followings:
Sour cherries: There were found differences in the cracking ratio and the cracking dynamics of the tested sour cherry varieties when they were immersed in distillated water for 24 hours. Based on cracking test results under laboratory condition (immersing in distillated water) we made the grouping by cracking susceptibility of sour cherry varieties. Tested cultivars were divided three groups: very susceptible; susceptible; moderately susceptible (tolerant). Groups with varieties are: Very susceptible - ’Maliga emléke’, ’Piramis’, ’Érdi jubileum’,’Érdi nagygyümölcsû’ and ’Meteor korai; Susceptible (Sensitive) – ’Érdi bôtermô’, ’Pándy’ and Cigány 59. Moderately susceptible (tolerant) – ‘Éva’ and ‘Petri’as new rereleases. The most of tested sour cherry varieties are in agreement with the literature (Apostol, 2003) and four of them (’Maliga emléke’, ’Pándy 279’, ‘Éva’ and ‘Petri’) had higher average fruit weight than was mentioned in the literature (Apostol, 2003). Our fruit cracking results are in agreement with Zelinski’s (1964) and Christensen’s (1975) conclusions that there is no close relationship between fruit size and rain induced fruit cracking tendency. We found significant differences between the sugar content of tested cultivars. In contrast of Verner & Blodget (1931) our results confirm Tucker’s opinion that the sugar content is not correlation with the cracking tendency of cherry fruits (Tucker, 1934). Fruits firmness (elasticity) was measured by destructive method when juice was coming out from fruits. There were found big differences of fruit firmness and skin strength of observed cultivars. Our results are only partly agreement with Christensen’s (1996) opinion that cherry cultivars with firmer fruits are more prone to fruit cracking than softer ones. By this was seemingly we did not found close relationship between the fruit firmness and the cracking tendency of sour cherry fruits. We found that during fruits immersing in distillated water the fruit weight was increasing due to the absorbed water. Our opinion is that there is no close relationship between the scale of fruit cracking and the quantity of absorbed water. By results presented above we our opinion is that no very close relationship between the fruit cracking of sour cherries and the observed parameters (fruit size, fruit firmness, sugar content, amount of absorbed water) maybe other varietal effects and physiological characters (fruit skin structural parameters) play more important role in the fruit cracking mechanism of cherries.Sweet cherries: Similarly to sour cherries in the case of sweet cherries we also did not find close relationship between observed fruit parameters and cracking index. It was differences in the cracking ratio and the cracking dynamics of the tested sweet cherry cultivars when they were immersed in distillated water for 24 hours. It was found that the cracking ratio of very cracking susceptible sour cherry varieties had the same or higher cracking index than observed sweet cherries. It is in contrast with the general opinion (Chistensen, 1996) that sour cherries are less prone to rain induced fruit cracking than sweet cherries. We found differences between the cracking ration and cracking dynamic of the same cultivar in different years (2006 and 2013). It is in agreement Christensen’s (1996) opinion that the year effect cause big differences in the fruit cracking of cherries.
European plums: We found differences in the cracking ratio and the cracking dynamics of the tested plum varieties when they were immersed in distillated water for 24 hours. A shorter term (6 hours) immersing in water caused three groups by their cracking susceptibility: „Very susceptible”: ’Révfülöpi’ and ’Szarvasi’; „Susceptible”: ’Besztercei’; „Less sensitive”: ’Bluefre’ and ’Cacanska rodna’. A longer term (24 hours) immersing in water resulted only two groups with significant differences: „Susceptible group”: ’Révfülöpi’, ’Szarvasi’ and ’Besztercei’; „Less sensitive”: ’Bluefre’ and ’Cacanska rodna’ Similarly the cherries we did not find correlation between the fruit size and cracking susceptibility of European plum cultivars. It was based on: the big fruit sized ‘Bluefre’ and middle sized ‘Cacanska rodna’ cracked in the lowest scale, during the small sized ’Révfülöpi’, ’Szarvasi’ and ’Besztercei’ cultivars cracked in higher scale We found positive correlations between the cracking susceptibility and total sugar content of tested plum cultivars. Cultivars with significantly lower sugar content (‘Bluefre’ and ‘C. rodna’) showed lower fruit cracking susceptibility than cultivars (’Révfülöpi’, ’Szarvasi’ and ’Besztercei’) with higher sugar content). We found close relationship between the relative (%) absorbed water amount and the fruit cracking susceptibility. Cultivars with higher absorbed water amount (’Szarvasi’-’Révfülöpi’-’Besztercei’) had higher cracking susceptibility. -
Fruit drop: The role of inner agents and environmental factors in the drop of flowers and fruits
13-23.Views:400The basic conditions of fruit set (synchronic bloom, transfer of pollen, etc.) still do decide definitely the fate of the flower (Cano-Medrano & Darnell, 1998) in spite of the best weather conditions (Stösser, 2002). Beyond a set quantity of fruits, the tree is unable to bring up larger load. A system of autoregulation works in the background and causes the drop of a fraction of fruits in spite of the accomplished fertilisation and the equality of physiological precedents (Soltész, 1997). There are also basically genetic agents in action. The further development of fruits maintained on the tree depends mainly on the growing conditions (e.g. water, supply of nutrients, weather adversities, pruning, fruit thinning, biotic damages, etc.), which may cause on their own turn fruit drop especially at the time of approaching maturity.
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Relation of sour cherry blooming dynamics and meteorological variables
17-23.Views:213The aim of our research was to identify the role of weather parameters in the development of the start date and length of blooming. In order to achieve this, we examined how meteorological conditions of a particular year influence the start date and length of blooming in different years (dry, wet, cool, hot, sunny, cloudy). The meteorological parameters were the following: maximum temperature, minimum temperature, average temperature, precipitation, length of sunlight, difference of daytime and nightime temperatures, potential evaporation-PET, Huglin-index,Winkler-index, climatic water balance which can be calculated as a difference of precipitation and potential evaporation. In this study we wanted to find out whether early start of blooming results in a longer blooming period or if there is a generally faster blooming period when blooming starts later. Based on the results we can say that early start of blooming resulted in extended blooming period for three sour cherry varieties at the examined production sites. The start of blooming showed the closest relation with the difference of average daytime and nightime temperatures of the 30-day period prior to blooming. Significant relation was also detected with the thermic indexes as well as with maximum temperatures, climatic water balance and the degree of potential evaporation.We examined how weather 30 days prior and during blooming influenced the length of phases. Results showed that precipitation prior and during blooming is in significant relation with the length of blooming. We detected significant relation between daytime and nightime temperature differences and the length of blooming. The nature of the relation indicates that blooming periods were shorter in case of increasing temperature differences.We found that shorter blooming lengths occurred when maximum temperatures averaged between 13.5–14.5 ºC 30 days prior to blooming when examining the relation between blooming length and maximum temperature. If the average of maximum temperatures was below 13 ºC or exceeded 15 ºC during this period, then we could calculate with a blooming period longer than ten days. We proved that little precipitation and high temperature accelerates physiological processes, therefore we could calculate with an accelerated blooming and shorter blooming period.
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Review of nutritional value and putative health-effects of quince (Cydonia oblonga Mill.) fruit
29-32.Views:440Quince (Cydonia oblonga Mill.) has been long regarded to be a health-promoting fruit. Although it is mainly consumed in processed form, its relatively heat-stable polyphenolics were confirmed to be responsible for most of the beneficial effects. This review aims to show basic nutritional information on quince fruit such as carbohydrate, fibre, pectin and mineral element contents. In addition, vitamin and polyphenolic contents and composition as well as the physiological effects of quince consumption were also surveyed. Information on presumable protective effects against several diseases including infl ammation, atopic dermatitis, ulcers and cancer is summarized. Potential antibacterial effects of quince polyphenolics were also considered. Polyphenolics are supposed to be responsible for the major part of benefi cial health-effects, and phenolic compounds predominantly accumulate in peel. There exists a considerable extent of genetic variation in phytochemical composition among cultivars, which might be exploited in designing future breeding programs for quince improvement and opening new ways for health-related uses.
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Ripening related processes in strawberry, a nonclimacteric fruit: a short overview
105-109.Views:189Fruits are essential part of the human diet: they provide vitamins, minerals, antioxidants to the mankind. Physiologically they can be divided into two groups-climacteric and nonclimacteric - depending if they display any respiratory peak and dramatic increase in ethylene biosynthesis or do not. Ethylene is a gaseous hormone playing a very important role in several physiological processes in plants. While climacteric fruits, like apples, bananas, tomatoes, peaches, apricots show increased ethylene biosynthesis and dramatic respiratory peak during their ripening, nonclimacteric fruits, like strawberries, grapes, citrus do not.
The most widely used fruits for studying nonclimacteric ripening are strawberries: several papers are focusing on the identification and characterization of ripening related genes from this plant. Therefore here we attempt to summarize the most important advances in strawberry fruit development, and ripening.
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Actual state of research concerning vitamin C as reflected in the literature (Review article)
7-15.Views:174Vitamin 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.