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Drought-induced Losses in Fruit Orchards
37-40Views:73Scientists investigating the causes of the extremities of climate that have become quite frequent in the Carpathian Basin over the past few years are quite often in doubts as to whether increased atmospheric warming and the shortage of rainfall are to be seen as recurrent natural phenomena under our climate, or the first signs of global warming. Climate anomalies have, to a certain extent, always been common in the Carpathian Basin. However, statistical data of the past few decades indicate that the rise in temperature and the fall in precipitation have, by now, become a tendency, which requires further in-depth scientific research.
The series of articles to be published in continuation of this paper endeavors to synthesize the research results and many years of experiences, in order to give an analysis of
I. The economic effects and the symptoms of drought in tree cultures
II. The possibilities of reducing the adverse affects of drought -
Changes of relative chlorophyll content at maize smut inoculated hybrids
55-58Views:223The leaf chlorophyll content analysis is important for several reasons. The natural or anthropogenic stressors directly effect on the chlorophyll content. Through the measurement of the chlorophyll content it is possible to obtain data concerning the physiological status of the plant, moreover the chlorophyll content is closely related to the nitrogen content, so it is linked to photosynthesis and the photosynthetic activity which determine biomass production.
One of the most common symptoms of plant diseases is the larger and smaller interveinal chlorotic areas. These might be local, or expand to the whole plant. There are multiply reasons of chlorosis such as reduction of chlorophyll content, unfavorable effects on the chlorophyll content,disorders regarding function of chloroplasts or ultimately destruction of the chloroplasts. Although such a chlorotic deviancy can contribute to significant losses in photosynthesis; however the underperformance photosynthesis of the sick plants is a more complex process.
As we unambiguously experienced during our investigations on common smut that the infected maize plants most common accompanying symptom was chlorosis on the leaves, so it is especially important to examine how the infection influenced on the chlorophyll content of different hybrids. -
Relation of availability and barley uptake of some potentially toxic elements
7-10Views:70A small-plot microelement load field trial was set up on brown forest clay soil with eight elements (Al, As, Cd, Cr, Cu, Hg, Pb, Zn), on 3 levels each (0/30, 90, 270 kg element ha-1). The soil was treated with soluble salts of elements once at initiation (1994). In the seventh year of the experiment (2001) winter barley was the test plant. The total element content was determined in plant samples (shoot, straw, grain) after microwave digestion using cc.HNO3+cc.H2O2. The element composition of the prepared samples was determined using ICP-MS technique. In the experiment toxic effects of treatments and yield loss could not be observed. Zn and As contents in barely shoots were only moderately increased by increasing microelement loads. Effects of Cr, Cu, Hg, Pb and Al treatments could not be observed. On the other hand, Cd accumulation was significant in the shoot. Cd content was also increased both in straw and grain. Results of this experiment prove that Cd remains mobile in the soil-plant system for a long time. Its accumulation can be observed both in vegetative and reproductive parts of plants without toxic symptoms and yield loss.
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The Effect of Grazing Intensities on Magnesium Contents
8-13Views:158Research was carried out on two areas of grassland in Hortobágy National Park, Hungary. Two herds of Hungarian Grey Cattle were kept in free range grazing and the effects of grazing pressure on the magnesium content of soil and ryegrass (Lolium perenne L) were determined.
Changes of plant available and total soil magnesium content under different grazing intensities did not show any evident tendency on the investigated grasslands. Different amounts of cattle faeces, urine and trampling had no effect on the magnesium concentration of ryegrass. We conclude that the magnesium content of ryegrass on both grassland sites as moderate grazing and overgrazing matches the requirements of cattle. Symptoms of magnesium deficiency of cattle will likely not appear. -
Investigation of the Resistance Against the Fusarium solani at Different Pea Varieties and Combinations of Breeding
157-160Views:32The Fusarium species are soil and polyphage parasits, and the rate of damage, caused by them, highly depend on interactions between climatic and edaphic factors and also on sensitivity of cultivars. Even though about 70-80 percent of the widely grown green peas cultivars is resistant to Fusarium oxysporum f. sp. pisi 1. race, the rate of Fusarium infections and severity of symptoms increased in the latest years. It is supposed that another Fusarium sp. the Fusarium solani has been spreading. The most exact way to study the cultivars in a provoking garden established in natural environment, where the pathogen is artificially enriched to a level, at which the cultivars can be distinguished according to their susceptibility. In the provoking garden the reaction against to Fusarium of our breeding lines and our registered cultivars and cultivars existed on the National List (including cultivars with well-known susceptibility as standards) are examined year by year. In our experiments we could found two green peas cultivars to be resistant to Fusarium solani (Early sweet (13,36%) and Lora (16,9%)) The breeding lines Margit and 8607/75-3-2 proved to be the most susceptible to Fusarium solani (94,4% and 73,1% infected plants, respectively).
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White rust species (Chromista, Peronosporomycetes, Albuginales, Albuginaceae) on common weeds in Hungary
30-33Views:206The obligate plant parasite fungi in the family Albuginaceae are responsible for causing white rust diseases on weeds and they are rather common worldwide. Weedy plants with characteristic symptoms have been collected in 2014 and 2015 on location Hajdú-Bihar and Jász-Nagykun-Szolnok counties in Hungary. The determination of the species were based on the morphological characters both pathogens and hosts. Albugo candida was determined on shepherd’s purse (Capsella bursa-pastoris). Common purslane (Portulaca oleracea) is a host for Wilsoniana portulacae. The fungus Wilsonia bliti (syn.: Albugo bliti), the causal agent of white rust disease was found on redroot pigweed (Amaranthus retroflexus).
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The Effect of Smut Gall Tumour Infection on Iron and Zinc Uptake and Distribution in Maize Seedlings
27-32Views:87The amounts of Fe, and Zn were measured in maize seedlings infected by smut gall tumour (Ustilago maydis Dc. Cda.) and in healthy seedlings five days after infection. The amount of elements was also measured under different stress intensities. Due to the infection, as a biotic stress, the amount and distribution of examined elements have been changed. On the bases of the differences in the Fe distribution between the symptoms less and tumorial leaf parts, we have come to the conclusion that the infection also effects the mobilisation of Fe and Zn inside the plants. The Fe uptake was much higher in the infected plants and the tumour development also had an effect on the uptake and distribution of the examined elements. The experiments of infecting maize seedlings by monosporidial strain of crown gall tumour showed no tumour development. We found that the monosporidial strain also acts as a biotic stress and has an effect of iron and zinc distribution. We observed a slight difference in the iron and zinc contents in the roots of corn seedlings infected by different monosporidial sporidium concentrations, while the iron and zinc contents in the shoots were increased by the intensity of the infection. The roots do not form tumours. There is no difference between the roots of the infected and healthy corn seedlings. Since the Fe and Zn contents of the shoots of infected plants depend on the intensity of the infection, we have come to the conclusion that there must exist a „special” communication system regulating the transportation of the examined elements.
In the experiments with infected maize seedlings, it became necessary to get the iron chlorosis before the disease reaches the lethal phase. Although most of the iron reserves are located in the embryo, to accelerate the chlorosis, the endosperm was removed, and it was observed, that the iron chlorosis appears later in maize seedlings when the endosperm is removed. The relative chlorophyll content of the first and second leaves was measured in iron efficient and iron deficient maize seedlings at different times.
The higher IAA content of tumorial plant tissues is already known. The treatment with IAA decreases the iron concentration in the shoots and in the roots of +Fe precultured plants and increases at -Fe precultured ones. The TIBA retards the shoot-to-root transport of IAA. When the seedlings were treated simultaneously with IAA and TIBA, higher iron concentrations were observed in the shoots and in the roots of corn seedlings.
We found extremely high iron concentrations in the roots of infected seedlings and, in line with this, serious damage to the roots was observed that this can be caused by the high iron content generated free radicals. The results demonstrate that IAA has a role in the shoot to root communication. -
Phytopatological properties of symbiotic Rhizoctonia solani strains associated to orchids
65-71Views:143The mycobiota of the Orchidarium of ELTE Botanical Garden (Budapest) has been studied applying aerobiological methods and isolating of tissue samples taken from 92 individuals of sixty orchid species. Among isolated basidiomycetaceous fungi 13 strains of Rhizoctonia solani were surviving in axenic culture. These symbiotic R. solani strains proved to be pathogenic on 24 cultivated plant species at varying degree. The symptoms of disease caused by R. solani strains isolated from orchids did not differ from that caused by reference strains. Three groups of strains could be separated regardless of their source or aggressivity. The host plants clustered into two groups, and their taxonomic position had no role in this respect. In general, we can assume that orchid associated Rhizoctonia strains are potential plant pathogens, and removed or withdrawn orchid stools should be treated as hazardous waste.
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The Impact of Water Supply on the Quality and Health of Potato
144-147Views:103Besides its effect on potato yield, water also has a significant impact on yield quality. Excess water (too much precipitation, over-irrigation) and the lack of water (lack of precipitation or irrigation) both trigger stress in the plant and can significantly worsen the quality of the yield (seed potato) and deteriorate the health of the plant and the seed potato. Excess precipitaton or irrigation water leaches nitrate-nitrogen under the rhizosphere, consequently, the amount of available nitrogen decreases leading to the deficiency of N in potato. If water cover (the maximally saturated state of soil) exceeds 8-12 hours, it can cause root destruction (because of the lack of oxygen), which leads to the wilting and later to the death of the plant. Abundance of water caused by excess precipitation or irrigation is a major problem primarily on sandy loam, loam and clay loam soils with bad structure and water management qualities, but also on any soils, which are over-irrigated or irrigated at an improper time. Symptoms of the lack of water are detectable mostly when the available water content of the soil (disponible water) decreases under 60-65%.
In the present year, there was a lack of precipitation on the Great Plain, which can be compensated by proper irrigation. Unfortunately, this problem is further intensified by the high temperature, which results in faster ripening and accompanied with fluctuating soil moisture content, in the formation of secondary tubers. -
Phytoplasma diseases on fruits in Hungary
24-29Views:158In the last twenty years, three phytoplasma diseases were identified in Hungary, viz. European Stone Fruit Yellows (ESFY) (caused by Candidatus Phytoplasma prunorum), pear decline (caused by Candidatus Phytoplasma pyri), and apple proliferation (caused by Candidatus Phytoplasma mali). Candidatus Phytoplasma prunorum was isolated from apricot, peach, plum and japanese plum. Cacopsylla pruni the vector of ESFY was also isolated and identified. Infection of Candidatus Phytoplasma pyri was diagnosed from pear and Candidatus Phytoplasma mali was found on apple and pear. The three phytoplasmas cause different damages on their host plants. The most economically important phytoplasma disease is the ESFY. It seriously impairs apricot and japanase plum trees. After infection of apricots and japanese plums show yellowing and defoliation, and within a few years die in apoplexy-like symptoms. The disease on japanese plum is so severe that this fruit practically can not be cultivated in Hungary. Pear decline is the most serious problem especially in intensive pear plantations. The vector Cacopsylla pyri, C. pyrisuga and C. pyricola can be found in almost all pear orchards. Because of the regular presence of psyllids in intensive pear orchards the insecticide control is necessary. Apple proliferation is not an important disease in Hungary. All of our isolations of ’Candidatus Phytoplasma mali’ occured in organic orchards and record was not available in Hungary lately.
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Comparison of Scab Warning Systems in Integrated Apple Production
53-57Views:55In the present study, the suggestions for infection risk and sprays of the most frequently used PC-based scab warning systems (RIMpro and WELTE) and the conventionally used Mills table as a reference were compared in integrated apple production. The efficacy of the spraying programs based on the three different warning systems was evaluated by assessment of apple scab incidences during primary infection periods.
13 and 11 Mills infection periods were detected in 2000 and 2001, respectively, during primary infection periods (from 15 March until 5 June). Taking into consideration the heaviness of Mills infection periods, 11 and 9 sprays were applied in 2000 and 2001, respectively. The two PC-based scab warning systems detected 1-4 less infection periods and suggested 1-3 less sprayings compared to the numbers of infection periods and sprays according to the Mills table. Our results proved that the 9-11 sprays according to the Mills table could be reduced to 7-9 sprays by RIMpro scab warning systems which did not reduce the efficacy and did not increase the symptoms of leaf and fruit scab significantly. The WELTE scab warning systems detected generally one or two more infection periods and suggested one additional spray compared to RIMpro warnings and sprays. -
Nutritional disorders of arable crop growth in eastern Croatia
273-290Views:136Nutritional imbalances accompanied with growth retardation of crops at early growth stage were found since the last 40 years on certain arable lands in eastern Croatia. In this regard, phosphorus (P) deficiencies in maize and wheat were found mainly on acid soils of the western part of the region, potassium (K) deficiencies in maize, soybean on the hydromorphic neutral to alkaline calcaric drained gleysols of Sava valley lowland, while zinc (Zn) deficiencies were observed mainly in seed-maize and soybean on neutral calcaric eutric cambisols of the eastern part of the region. Cold and moist spring is factor promoting P deficiency symptoms. As oasis of normal crops existed on same arable land, comparison of plant and soil composition was possible from typical sites. P nutrition disorders were in connection with the lower P and the higher aluminum (Al) and iron (Fe) concentrations in the top of plants and the lower soil pH values. K-deficiency as result of strong K fixation and imbalances with high levels of magnesium (Mg) were the main responsible factors of low maize and soybean yields on some drained gleysols. Chlorosis incidences typical for Zn deficiency in maize and soybean were in close connection with the higher soil pH, the lower quantities of mobile Zn, here and there the higher mobile P in soil, the lower concentrations of Zn and the higher levels of Al and Fe in plants. Overcoming the above mentioned disorders and normalization of yields were achieved using ameliorative fertilization either by K or P fertilizers and in case of Zn by foliar spraying of crops with 0.75% ZnSO4 solution. Also, alleviations are possible by selection of more tolerant genotypes of field crops to specific types of nutritional disorders. From this aspect, some practical solutions were recommended for maize with reference to K nutritional problems.