Biomass production of Lolio‐Cynosuretum grassland is not increased by plant‐species richness          下载免费PDF全文

Melanie Seither  Nicole Wrage‐Mönnig  Johannes Isselstein 《植物养料与土壤学杂志》2014,177(4):613-623

In experimental grasslands, a positive relationship between biomass production and plant diversity has often been found. Here, we compared a moderately species‐rich old sward with its grass‐dominated counterpart (12 vs. 8 species per 2.5 m², or 8.3 vs. 0.7% yield proportion of dicots at the start of the experiment) established by herbicide application. We hypothesized an increased N, P and K uptake in the diverse sward related to a higher colonization rate with arbuscular mycorrhizal fungi (AMF), the presence of legumes, and complementary nutrient use of plant species. Phosphorus or N fertilizer application (according to contributions of AMF or legumes) were expected to balance the assumed smaller biomass production of the grass compared to the diverse sward. In two experimental years, N, P and K uptake, biomass production, N₂ fixation, and intra‐ and extraradical AMF colonization were investigated in an untreated control and plots that were fertilized with P and N in a low (P1: 20 kg P ha^?1; N1: 50 kg N ha^?1) or a high dose (P2: 100 kg P ha^?1; N2: 500 kg N ha^?1) in both swards. Biomass production was larger in the grass compared to the diverse sward. The N, P and K uptake, accumulated over three harvests (or 1.5 years), was also larger in the grass sward. The biomass production ranged from 5.3 to 10.0 t ha^?1 and accumulated nutrient uptake from 82 to191 kg N ha^?1, 19 to 31 kg P ha^?1 and 112 to 221 kg K ha^?1. Small legume proportions resulted in an accumulated N₂ fixation between 0 and 3 kg ha^?1. In the second year, the root length colonized with AMF structures was larger in the diverse compared to the grass sward, and the root length colonized with arbuscules and coils was larger in the N2 treatment compared to the control in the diverse sward. There were hints to higher AMF abundance under conditions of limited P availability (low soil P content, high N:P ratio in plant biomass). We conclude that in semi‐natural grassland of moderate species richness several factors may affect the relationship between plant diversity and productivity, i.e., management, plant species identity, and the number of the plant species of the low‐diversity level.  相似文献   

Effects of activated charcoal and tannin added to compost and to soil on carbon dioxide,nitrous oxide and ammonia volatilization          下载免费PDF全文

Greta Jordan  Martina Predotova  Mariko Ingold  Sven Goenster  Herbert Dietz  Rainer Georg Joergensen  Andreas Buerkert 《植物养料与土壤学杂志》2015,178(2):218-228

Given high mineralization rates of soil organic matter addition of organic fertilizers such as compost and manure is a particularly important component of soil fertility management under irrigated subtropical conditions as in Oman. However, such applications are often accompanied by high leaching and volatilization losses of N. Two experiments were therefore conducted to quantify the effects of additions of activated charcoal and tannin either to compost in the field or directly to the soil. In the compost experiment, activated charcoal and tannins were added to compost made from goat manure and plant material at a rate of either 0.5 t activated charcoal ha^?1, 0.8 t tannin extract ha^?1, or 0.6 t activated charcoal and tannin ha^?1 in a mixed application. Subsequently, emissions of CO₂, N₂O, and NH₃ volatilization were determined for 69 d of composting. The results were verified in a 20‐d soil incubation experiment in which C and N emissions from a soil amended with goat manure (equivalent to 135 kg N ha^?1) and additional amendments of either 3 t activated charcoal ha^?1, or 2 t tannin extract ha^?1, or the sum of both additives were determined. While activated charcoal failed to affect the measured parameters, both experiments showed that peaks of gaseous CO₂ and N emission were reduced and/or occurred at different times when tannin was applied to compost and soil. Application of tannins to compost reduced cumulative gaseous C emissions by 40% and of N by 36% compared with the non‐amended compost. Tannins applied directly to the soil reduced emission of N₂O by 17% and volatilization of NH₃ by 51% compared to the control. However, emissions of all gases increased in compost amended with activated charcoal, and the organic C concentration of the activated charcoal amended soil increased significantly compared to the control. Based on these results, tannins appear to be a promising amendment to reduce gaseous emissions from composts, particularly under subtropical conditions.  相似文献   

Levantilides A and B, 20-membered macrolides from a Micromonospora strain isolated from the Mediterranean deep sea sediment     

Gärtner A  Ohlendorf B  Schulz D  Zinecker H  Wiese J  Imhoff JF 《Marine drugs》2011,9(1):98-108

Two new 20-membered macrolides, levantilide A and B, were isolated from the Micromonospora strain M71-A77. Strain M71-A77 was recovered from an Eastern Mediterranean deep-sea sediment sample and revealed to produce the levantilides under in situ salinity of 38.6 ‰. The chemical structures of the levantilides were elucidated on the basis of different one- and two- dimensional NMR experiments. Levantilide A exhibits a moderate antiproliferative activity against several tumor cell lines.  相似文献   

Comparison of the Effects of Four Freezing Methods on Motility Characteristics,Morphology, and Viability of Postthaw Stallion Epididymal Sperm     

Stefanie Neuhauser  Svenja Rheinfeld  Johannes Handler 《Journal of Equine Veterinary Science》2014

Semen cryopreservation is of growing interest in the horse breeding industry, and collecting epididymal sperm might provide the chance to preserve genetic material from valuable stallions after severe injury or death. In case of an unexpected emergency, there may not always be an adequate laboratory nearby. Therefore, we compared fast and slow freezing methods using either a programmable freezer or a styrofoam box filled with liquid nitrogen. Epididymides of 10 stallions were collected immediately after routine castration under general anesthesia. Epididymal spermatozoa were evaluated before and after the freeze-thaw process for motility, viability, morphological, and kinematic parameters. Neither postthaw motility nor kinematic values differed among the four freezing protocols. Morphological abnormalities after freezing and thawing differed among epididymal segments. However, there were significantly more nonviable spermatozoa after the freeze-thaw process using the fast freezing process in the styrofoam box filled with liquid nitrogen compared with all other freezing processes. According to the results of this study, freezing in nitrogen vapor should be considered as an alternative to the programmable freezer only in combination with a prolonged cooling period.  相似文献   

Comparison of respiratory function during TIVA and isoflurane anaesthesia in ponies Part II: breathing patterns and transdiaphragmatic pressure     

Stijn Schauvliege  Johannes Peter Schramel  Kiriaki Pavlidou  Ioannis Savvas  Luc Duchateau  Frank Gasthuys  Yves Moens 《Veterinary anaesthesia and analgesia》2014,41(6):592-601

ObjectiveTo compare breathing patterns and transdiaphragmatic pressure during total intravenous (TIVA) and isoflurane anaesthesia in ponies.Study designExperimental, cross–over study.AnimalsSix healthy ponies weighing 286 (233–388) ± 61 kg, age 13 (9–16) ± 3 years.MethodsFollowing premedication with romifidine [80 μg kg^?1 intravenously (IV)], general anaesthesia was induced with midazolam (0.06 mg kg^?1 IV) and ketamine (2.5 mg kg^?1 IV) and maintained with either isoflurane (Fe’Iso = 1.1%) (T-ISO) or an IV combination of romifidine (120 μg kg^?1 per hour), midazolam (0.09 mg kg^?1 hour^?1) and ketamine (3.3 mg kg^?1 hour^?1) (T-TIVA), while breathing 60% oxygen (FIO₂). The circumference changes of the rib cage (RC) and abdominal compartment (ABD) were recorded using respiratory ultrasonic plethysmography (RUP). Balloon tipped catheters were placed in the distal oesophagus and the stomach and maximal transdiaphragmatic pressure (P_{di max)} was calculated during Mueller's manoeuvre.ResultsThe breathing pattern T-ISO was more regular and respiratory rate significantly lower compared with T-TIVA. Ponies in T-TIVA showed regularly appearing sighs, which were never observed in T-ISO. Different contribution of the RC and ABD compartments to the breathing pattern was observed with a smaller participation of the RC to the total volume change during T-ISO. Transdiaphragmatic pressures (mean 13.7 ± SD 8.61 versus 23.4 ± 7.27 cmH₂O, p < 0.0001) were higher in T-TIVA compared to T-ISO. The sum of the RC and ABD circumferential changes was lower during T-TIVA compared to T-ISO (6.32 ± 4.42 versus 11.72 ± 4.38 units, p < 0.0001).Conclusion and clinical relevanceMarked differences in breathing pattern and transdiaphragmatic pressure exist during inhalation- and TIVA and these should be taken into account for clinical estimation of anaesthetic depth.  相似文献   

Variety of non‐invasive continuous monitoring methodologies including electrical impedance tomography provides novel insights into the physiology of lung collapse and recruitment – case report of an anaesthetized horse     

Yves Moens  Johannes P Schramel  Gerardo Tusman  Tamas D Ambrisko  Josep Solà  Josef X Brunner  Lidia Kowalczyk  Stephan H Böhm 《Veterinary anaesthesia and analgesia》2014,41(2):196-204

IntroductionThe use of alveolar recruitment maneuvers during general anaesthesia of horses is a potentially useful therapeutic option for the ventilatory management. While the routine application of recruitments would benefit from the availability of dedicated large animal ventilators their impact on ventilation and perfusion in the horse is not yet well documented nor completely understood.Case historyA healthy 533 kg experimental horse underwent general anaesthesia in lateral recumbency. During intermittent positive pressure ventilation a stepwise alveolar recruitment maneuver was performed.ManagementAnaesthesia was induced with ketamine and midazolam and maintained with isoflurane in oxygen using a large animal circle system. Mechanical ventilation was applied in pressure ventilation mode and an alveolar recruitment maneuver performed employing a sequence of ascending and descending positive end expiratory pressures. Next to the standard monitoring, which included spirometry, additionally three non-invasive monitoring techniques were used: electrical impedance tomography (EIT), volumetric capnography and respiratory ultrasonic plethysmography. The functional images continuously delivered by EIT initially showed markedly reduced ventilation in the dependent lung and allowed on-line monitoring of the dynamic changes in the distribution of ventilation during the recruitment maneuver. Furthermore, continuous monitoring of compliance, dead space fraction, tidal volumes and changes in end expiratory lung volume were possible without technical difficulties.Follow upThe horse made an unremarkable recovery.ConclusionThe novel non-invasive monitoring technologies used in this study provided unprecedented insights into the physiology of lung collapse and recruitment. The synergic information of these techniques holds promise to be useful when developing and evaluating new ventilatory strategies in horses.  相似文献   

Linking food systems and landscape sustainability in the Mediterranean region     

García-Martín  María  Torralba  Mario  Quintas-Soriano  Cristina  Kahl  Johannes  Plieninger  Tobias 《Landscape Ecology》2021,36(8):2259-2275

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Sex identification in Encephalartos natalensis (Dyer and Verdoorn) using RAPD markers     

Surya Prakash  Johannes Van Staden 《Euphytica》2006,152(2):197-200

All cycads are strictly dioecious with a long juvenile stage. Currently, there is no method available to determine the sexuality of seedlings prior to the onset of cone formation. This study aimed to develop a sex specific Random Amplified Polymorphic DNA (RAPD) marker for Encephalartos natalensis. Initially, 140 primers were used to amplify the bulk DNA of five individuals each of known male and female sexuality. While a high degree of polymorphism was observed in the amplification profiles of male and female plants, only primer OPD-20 generated a specific band (∼850 bp) in female DNA. To validate this observation, this primer was re-tested with 69 individuals of E. natalensis. The 850 bp DNA band was present in all 38 female individuals tested and it was consistently absent in all 31 male plants tested. The result offers a rapid and simple test to determine sexuality of E. natalensis seedlings at early stages of development, before the onset of reproductive maturity thereby saving time and economic resources when cultivating these specimens.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .  相似文献   

Effects of some conventional insecticides and insect growth regulators on different phenological stages of the white wax scale,Ceroplastes destructor Newstead (Hemiptera: Coccidae), and its primary parasitoid,Aprostocetus ceroplastae (Girault) (Hymenoptera: Eulophidae)     

Waktola Wakgari  Johannes Giliomee 《国际虫害防治杂志》2013,59(3):179-184

The toxicity of two juvenile hormone analogues, pyriproxyfen (Nemesis^®) and fenoxycarb (Insegar^®), and two contact insecticides, methomyl (Lannate) and methidathion (Ultracide), was evaluated against immature stages (LI, LII, LIII) of Ceroplastes destructor Newstead in the field. The effects of these chemicals and one moulting inhibitor, triflumuron (Alsystin^®), and three insecticides: methyl-parathion (Penncap-M), profenofos (Selecron) and prothiofos (Tokuthion), on Aprostocetus (= Tetrastichus) ceroplastae (Girault) were assessed in the laboratory. Development of the first and second instar nymphs of C. destructor was completely arrested by the chemicals. Less than 1% of scales sprayed with pyriproxyfen at LII stage survived to adult female. Survival to the adult stage varied significantly between chemical treatments, and between chemicals and untreated controls for scales sprayed at the LIII stage. Female fecundity, fertility and body sizes of survivors of treatments applied at the LIII stage were not significantly affected by any of the chemicals. All the chemicals exhibited high toxicity to A. ceroplastae. Only triflumuron was slightly harmful, while methomyl was the most toxic (harmful), causing 100% mortality in the first 30 min after treatment. Although all the chemicals evaluated had effectively arrested the first and second instars of C. destructor, none of them exhibited sufficient selectivity to A. ceroplastae to warrant recommendation for integrated management of C. destructor in citrus orchards in South Africa, where A. ceroplastae plays an important role.  相似文献   

Identification of beer bitter acids regulating mechanisms of gastric acid secretion     

Walker J  Hell J  Liszt KI  Dresel M  Pignitter M  Hofmann T  Somoza V 《Journal of agricultural and food chemistry》2012,60(6):1405-1412

Beer, one of the most consumed beverages worldwide, has been shown to stimulate gastric acid secretion. Although organic acids, formed by fermentation of glucose, are known to be stimulants of gastric acid secretion, very little is known about the effects of different types of beer or the active constituents thereof. In the present study, we compared the effects of different beers on mechanisms of gastric acid secretion. To investigate compound-specific effects on mechanisms of gastric acid secretion, organic acids and bitter compounds were quantified by HPLC-DAD and UPLC-MS/MS and tested in human gastric cancer cells (HGT-1) by means of a pH-sensitive fluorescent dye which determines the intracellular pH as an indicator of proton secretion. The expression of relevant genes, coding the H(+)/K(+)-ATPase, ATP4A, the histamine receptor, HRH2, the acetylcholine receptor, CHRM3, and the somatostatin receptor, SSTR2, was determined by qPCR. Ethanol and the organic acids succinic acid, malic acid, and citric acid were demonstrated to contribute to some extent to the effect of beer. The bitter acids comprising α-, β-, and iso-α-acids were identified as potential key components promoting gastric acid secretion and up-regulation of CHRM3 gene expression by a maximum factor of 2.01 compared to that of untreated control cells with a correlation to their respective bitterness.  相似文献