Current knowledge and breeding perspectives for the miracle plant Synsepalum dulcificum (Schum. et Thonn.) Daniell     

Enoch G. Achigan-Dako  Dèdéou A. Tchokponhoué  Sognigbé N’Danikou  Jens Gebauer  Raymond S. Vodouhè 《Genetic Resources and Crop Evolution》2015,62(3):465-476

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Reproductive physiology of the stallion: daily sperm output and testicular measurements     

M R Gebauer  B W Pickett  J L Voss  E E Swierstra 《Journal of the American Veterinary Medical Association》1974,165(8):711-713

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Auswirkungen des Klimawandels auf die Verfügbarkeit von Kältewirkung (Chilling) für Obstgehölze in Deutschland     

Eike Luedeling  Michael Blanke  Jens Gebauer 《Erwerbs-Obstbau》2009,51(3):81-94

To quantify the effects of climate change on fruit production in Germany, this study aimed at determining long-term trends in winter chill, as calculated with the Chilling Hours and Dynamic Models (Chill Portions). An idealized daily temperature curve was used to convert daily temperature records from 43 weather stations, taken throughout the twentieth and late nineteenth centuries, into an hourly dataset, which was then converted to units of winter chill. Besides exposing temporal trends in winter chill, the data could be spatially interpolated, yielding contiguous maps of typical winter chill in Germany around 2010, as well as chilling losses since 1950. Throughout Germany, winter chill varied between 1700 and 3000 Chilling Hours or 125 and 150 Chill Portions. The areas of highest winter chill were located in the northern parts of the country. For the whole of Germany, there were no significant temporal trends. The extent of interregional variation in winter chill depended on the chilling model used. While the Chilling Hours Model showed strong declines in winter chill for the areas around Dresden and Leipzig, as well as for the Lake Constance region, the Dynamic Model did not detect such dramatic changes. More than a decline in winter chill, increased heat during the winter months might become a challenge to German fruit growers. As already experienced during the extraordinarily warm winter of 2006/07, warm temperatures during the winter can cause fruit trees that fulfill their chilling requirements relatively early to bloom prematurely. This can then lead to elevated risk of frost damage and hamper the homogeneity of flowering.  相似文献   

Nitrogen uptake from 15N-enriched fertilizer by four tree crops in an Amazonian agroforest     

Harald Dinkelmeyer  Johannes Lehmann  Andreas Renck  Lucerina Trujillo  Jose Pereira da Silva Jr  Gerhard Gebauer  Klaus Kaiser 《Agroforestry Systems》2003,57(3):213-224

Mixed tree cropping systems have been proposed for sustainable nutrient management in the humid tropics. Yet, the nutrient interactions between intercropped trees have not been addressed sufficiently. In the present study we compare the temporal and spatial patterns of the uptake of applied ¹⁵N by four different tree crops in a mixed tree cropping system on a Xanthic Ferralsol in central Amazônia, Brazil, during one year. Most of the N uptake occurred during the first two weeks. Very little N was recovered by peach palm (Bactris gasipaes), more by cupuassu (Theobroma grandiflorum) and annatto (Bixa orellana) and most by Brazil nut (Bertholletia excelsa). Due to tree pruning the total accumulation of applied ¹⁵N in the above-ground biomass of annatto decreased throughout the year. It remained constant in cupuassu and peach palm and increased in Brazil nut. Brazil nut showed an extensive root activity and took up more fertilizer N applied to neighboring trees than from the one applied under its own canopy in contrast to the other three tree crops. Therefore, trees with wide-spread root systems may not need to receive N fertilizer directly but can take up N applied to other trees in the mixed cropping system. This means that such trees may effectively decrease N leaching when intercropped with trees that have dormant periods or places with low N uptake, but also exert considerable resource competition.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

Nitrogen recovery in a decoupled aquaponic system with lamellar settler and trickling biofilter: implications for system management     

Gebauer  Radek  Lehman  Liliana  Monsees  Hendrik  Rennert  Bernhard  Mráz  Jan  Kloas  Werner 《Aquaculture International》2022,30(4):2043-2058

Careful nitrogen (N) management will be needed to nourish the growing human population while minimizing adverse environmental impacts. Aquaponic systems (AS) have a great potential to become a sustainable technology making further use of N-rich aquaculture wastewater. In the present study, we observed the N retention and losses in a running prototype of decoupled AS with Nile tilapia (Oreochromis niloticus) and tomatoes (Solanum lycopersicum) over 24 days. N losses amounted to 32.5% of feed N input and were observed in the recirculating aquaculture system (RAS) of the AS. Fish retained 21.1% of N input while 25.2% of N input accumulated in the RAS water. About 14.1% of the loss of N was caused probably by anaerobic denitrification processes in the lamellar settler (LS). In addition, 18.4% of N input was discharged during the three cleanings of LS. In the hydroponic unit of the AS that has been due to space limitations much smaller than an optimized AS could be (only about 20% of the optimal size relative to fish biomass), the tomato plants, including fruits, leaves, and stems, recovered 3.1% of N input with water uptake of 1700 L. The fish culture management, system design, and environmental management in the greenhouse affect the N recovery in the decoupled AS.

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Effect of thinning on anatomical adaptations of Norway spruce needles     

Gebauer R  Volarík D  Urban J  Børja I  Nagy NE  Eldhuset TD  Krokene P 《Tree physiology》2011,31(10):1103-1113

Conifers and other trees are constantly adapting to changes in light conditions, water/nutrient supply and temperatures by physiological and morphological modifications of their foliage. However, the relationship between physiological processes and anatomical characteristics of foliage has been little explored in trees. In this study we evaluated needle structure and function in Norway spruce families exposed to different light conditions and transpiration regimes. We compared needle characteristics of sun-exposed and shaded current-year needles in a control plot and a thinned plot with 50% reduction in stand density. Whole-tree transpiration rates remained similar across plots, but increased transpiration of lower branches after thinning implies that sun-exposed needles in the thinned plot were subjected to higher water stress than sun-exposed needles in the control plot. In general, morphological and anatomical needle parameters increased with increasing tree height and light intensity. Needle width, needle cross-section area, needle stele area and needle flatness (the ratio of needle thickness to needle width) differed most between the upper and lower canopy. The parameters that were most sensitive to the altered needle water status of the upper canopy after thinning were needle thickness, needle flatness and percentage of stele area in needle area. These results show that studies comparing needle structure or function between tree species should consider not only tree height and light gradients, but also needle water status. Unaccounted for differences in needle water status may have contributed to the variable relationship between needle structure and irradiance that has been observed among conifers.  相似文献   

First record of <Emphasis Type="Italic">Grewia tenax</Emphasis> (Forssk.) Fiori in northern Oman,a valuable fruit producing shrub     

J. Gebauer  A. Patzelt  K. Hammer  A. Buerkert 《Genetic Resources and Crop Evolution》2007,54(6):1153-1158

Grewia tenax (Forssk.) Fiori is a wild fruit species with multiple uses in different parts of the Tropics and Subtropics. It is common on the Arabian Peninsula and has also been recorded in southern Oman. To date, no record of the species exists for the northern part of this country. To close this distributional gap, three sites in the al-Hajar mountains of northern Oman were surveyed in summer 2005 and spring 2006. During the botanical fieldwork, several flowering and fruiting plants were found in Wadi Bani Awf and Wadi Muaydin. In the latter area G. tenax fruits are eaten by local people. In addition to G. tenax, nine woody perennials with edible fruit were recorded. In northern Oman, fruits of Sideroxylon mascatense (A. DC.) Penn. and Ziziphus spina-christi (L.) Desf. are widely collected and sold on local markets. G. tenax shrubs were found to be heavily grazed indicating its high palatability to goats and sheep. The occurrence of G. tenax in the al-Hajar mountains is a new record to the flora of northern Oman and calls for further investigation of botanists and germplasm collectors.  相似文献   

Photosynthetic water‐use efficiency of irrigated winter and summer crops in a typical mountain oasis of northern Oman     

Sabine D. Golombek  Jens Gebauer  Andreas Buerkert 《植物养料与土壤学杂志》2007,170(1):98-105

The millenia‐old existence of traditional, surface‐irrigated Omani mountain oases implies a remarkable sustainability of such systems in a hyperarid environment. This study was conducted in the mountain oasis of Balad Seet, situated in the Al‐Jabal‐al‐Akhdar mountains of northern Oman, to investigate the water‐use efficiency (WUE) of these oases and how farmers regulate it. In 2005, gas exchange of single leaves of 9–16 plants was measured for the most important perennial field crop alfalfa in both February and August, for the typical winter crop oat in February, and the dominating summer crop sorghum in August. The measurements were conducted five times a day in subplots irrigated the evening before and in the surrounding control plots, where plants had been withheld from irrigation for 14–16 d. Water deficit at the end of the irrigation interval reduced the stomatal conductance (g_s) strongly in summer alfalfa, oat, and sorghum, but only slightly in winter alfalfa. In oat, the reduction of net photosynthetic rate (P_N) at the end of the irrigation cycle was caused mainly by stomatal closure, in sorghum by nonstomatal factors and in summer alfalfa by both, whereas P_N in winter alfalfa remained unaffected. The ratio of net photosynthetic rate to stomatal conductance (P_N/g_s), the “intrinsic water‐use efficiency”, increased in all investigated crops in response to drought because of a stronger reduction of g_s than of P_N. This increase was small in winter alfalfa, but much stronger in oat, sorghum, and summer alfalfa. The data indicate that alfalfa maintains a relatively high CO₂ assimilation rate year‐round, contributing to a relatively high annual dry‐matter production. The decrease of the light intensity in the late afternoon caused by the shading effect of the surrounding mountains diminishes the crop evapotranspiration in the oasis.  相似文献   

Vitamin E und B in Pflanzen     

Gebauer  H. 《Plant foods for human nutrition (Dordrecht, Netherlands)》1958,3(1):381-392

Zusammenfassung Aus dem Forschungsgebiet des Vitamin E wird mitgeteilt, daß zwischen der Keimfähigkeit und dem Tocopherolgehalt des Roggens und Weizens Wechselbeziehungen bestehen, desgleichen zwischen dem Tocopherol- und Ölgehalt der Paprikafrucht und der Sanddornbeere. Besondere Erwähnung findet der B-Vitamingehalt der Fruchtsäfte, deren Veredelungsprodukte sowie deren Trester. Auf die Komplexwirkung dieser Fruchtsäfte, sowie verschiedener Gemüsearten wird an Hand einiger Wachstumsversuche an Albinoratten hingewiesen.

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Summary The rate of vitamin E in cereal-oil is reduced a great deal by stockage of the cereals. Diminution is roughly parallel with diminution of germinative power. Vitamin of B group (B₁, B₂, nicotinamide, inositol) is found in mark juices in greater quantities than in clarified juice. Rats, at diet rich in coco grease and vitamin, died from enteritis fastely. Introduction in food of little quantities of raw vegetables tolerates a normal growth of these animals.

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Résumé Le taux de vitamine E des huiles de céréales diminue beaucoup par stockage des céréales; la diminution est grossièrement parallèle à la diminution du pouvoir germinatif. Les vitamines du groupe B (B₁, B₂ nicotinamide, inositol) se rencontrent dans les marcs de fruits beaucoup plus abondamment que dans le jus clarifié. Des Rats soumis à un régime riche en graisse de coco, et riche en vitamines, meurent d'entérite assez rapidement; l'introduction dans la nourriture de petites quantités de légumes crus permet une croissance normale de ces animaux.

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Vitamine und Pflanzen     

Gebauer  H. 《Plant foods for human nutrition (Dordrecht, Netherlands)》1958,3(1):161-165

Zusammenfassung In kurzen Übersichten werden einzelne Forschungsthemen besprochen, die in der ehemaligen Anstalt für Vitaminforschung und Vitaminprüfungin Potsdam-Rehbrücke bearbeitet werden. Erwähnt wird der Ascorbinsäuregehalt der Kartoffel während der Lagerung und des Sanddornbeerensaftes nach verschiedenen Konservierungsverfahren, sowie die Verschiebung der Verhältnisse zwischen Ascorbinsäure und Dehydroascorbinsäure in Sonnenblumensamen nach der Ernte.

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Summary The rate of vitamine C is reduced during the storage of potatoes, pending the winter, but augments, in the same samples, in the spring, at the time of germination starting. The rate in vitamin C of theHippophaë Rhamnoïdes juice decreases with 9/10 after pasteurisation and 4 months of conservation. Diminution is only by half after sterilisation by ultraviolet or infrared rays.

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Résumé La teneur en vitamine C diminue au cours de la conservation en magasin des pommes de terre durant l'hiver, mais augmente dans les mêmes échantillons au printemps, au moment du départ des germes. La teneur en vitamine C du suc d'Hippophaë Rhamnoïdes diminue des 9/10 après pasteurisation et 4 mois de conservation; la diminution n'est que de moitié après stérilisation par l'ultraviolet ou l'infrarouge.

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Bericht über eine Auswahl von Forschungsthemen aus der ehemaligen Anstalt für Vitaminforschung in Potsdam-Rehbrücke, die sich mit einzelnen Vitaminen in der Pflanze beschäftigen  相似文献