The aim of the study was the study of winter frost damages, especially their changes expressed in temporal frequencies on the main fruit growing regions of the country. In our earlier paper, we introduced the calculation with the term LT50 as the quantitative expression of temperature threshold, when the lethality halves the survival of plant o...rgans, buds or cells causing 50% death rate. The damage is highly dependent on the temperature and on its duration (length of time), but not at least on the frost tolerance of the fruit trees. The incidence and severity of damage is analysed according to the apricot and peach varieties of their different susceptibility or tolerance too. Four fruit growing regions, two of the in Transdanubia and two belonging to the regions east of the Tisza river have been selected to trace the incidence and severity of frost damages. For that purpose, we analysed the history of the past 60 year period, 1951–2010, utilising the database of the network of 16 meteorological stations of the countrywide service. Being aware of the values of LT50 during the rest period and afterward, the compulsory dormancy caused by low temperature, the number of days, the probability of frost damage could be predicted. The role of the orographical profi le, the height above sea level and the exposition of plantations are also decisive. Within the same plantation, 20–30 m difference of level may cause large diversity in temperature and frost damage. Air circulation and regular incidence of winds within the Carpathian basin modify the occurrence and severity of damages. Lowlands near the southern and northern country borders are particularly exposed to winter frosts. Most damages are reported in February, as temperatures below –20 °C especially if the fi rst part of the winter was mild, or in January was a warm period. With the end of the physiological rest period of the trees, the frost-susceptibility increases signifi cantly, and a cold period of –15 °C may cause heavy damage. This study proves that tolerance of varieties infl uence the damages substantially. By planting frost tolerant varieties, winter frost damages could be diminished by 40–50% at the same growing sites. Present results may also offer a tool to estimate the risk of frost damages and express the security of yields at a given site based on the data accumulated in the database over many years.
Nowdays it is generally expressed opinion of the leading scientific circles that the purposefully planned biotechnological actions of the 21st century will be indispensable of realizing the sustainable technical development in the supplementation of the increasing population, especially those who suffer privation, thus the long-distance interes...ts of mankind will be met without impairing the world's ecological integrity. In 1989 Robert Bud gave account of the fact that the father of the term "biotechnology" was the Hungarian agricultural engineer, Karl Ereky. Recently, we have explored and found some important biographical sources and scientific documents which had been published by Károly (Karl) Ereky, the which, however, have already been forgotten. This article expands on that more contextual treatment to explore the man and his doctrine. It draws upon Hungarian and private sources as well as on German publications.
The knowledge of tissue culture deserves attention in respect of understanding the development of universal biology. This study intends to contribute to the past of the plant tissue culture by such data of the history of science which have been unprocessed so far. It seems that the life-work of the Hungarian biologist, Dr. Ottó Orsós is a mis...sing and essential link between those early plant hormone researchers and the representatives of the pioneers of tissue culture schools who have contributed substantially to the development of the modern in vitro plant morphogenesis and plant cell biology. Orsós cultured kohlrabi tuber cubes on White culture medium in a sterile manner. This way, he could efficiently direct the in vitro morphogenesis of the kohlrabi, the regeneration of its shoot and root, and the formation and steps to subculture of pure callus tissues in 1938. He supported the correctness of its statements by means of detailed anatomical examinations. Orsós successfully rooted and aclimatized complete regenerated plants. We may as well call the above system — in remembrance of the creators of the original concept — "Haberlandt-Orsós model". Between the publishing of his main paper in 1938 and 2003, a period of 65 years has lapsed. On the occasion of this anniversary, we bow before this forgotten pioneer.
The widespread genus Cotoneaster has its centre of diversity in the Himalayas and surrounding areas. Most taxa appear to be polyploid and apomictic, and many of them have become popular ornamentals due to their attractive foliage and berries. One of the taxonomically most critical groups is Section Alpigeni which contains seve...ral important ornamental plants. The number of species belonging to this section varies widely between different taxonomic treatises, depending on whether 'splitting' or 'lumping' of species is preferred. Using a rather narrow species definition, we have investigated 13 different species using RAPD analysis. A simple matching (SM) coefficient-based principle coordinate analysis (PCO) was calculated from the RAPD data. Some species were clearly more similar to each other than to other species in the analysis. The levels of similarity did, however, not correspond very well to the lumping together of several taxa under the same species name as performed e.g. in the recent Flora of China. Obviously, the complex hybridogenous origination and, in some cases, still ongoing recombination with sexual species or among the apomictic taxa themselves, produces a genetic variability structure that cannot be properly reflected in a hierarchical taxonomy.