网室内作物蒸散量的变化和影响要素研究

在香蕉种植网室内,研究了网室内外作物蒸散量和参考作物蒸散量的关系,以及网室内小气候变化对参考作物蒸散量的影响.研究结果显示,网室内参考作物蒸散量(ET0)和A级蒸发皿水面蒸发量分别比大田减少39%和42%,网室内香蕉树蒸腾量较网室外下降53%.网室内净辐射降低和风速减小是网室内香蕉树蒸腾量和参考作物蒸散量降低的主要原因,而网室内温度和饱和水汽压差变化对蒸散量的影响较小.建立了网室内参考作物蒸散量和网室内外水面蒸发量的关系,计算出该地区的A级蒸发皿系数为0.84.     

Potential Nitrate Leaching Under Common Landscaping Plants

Two Elsholtzia haichowensis S. populations, copper-tolerant (TLS) and non-tolerant (HA) ones were studied in hydroponic experiment for the nitrogen assimilation and plant growth under excess Cu conditions. The results demonstrated that there were surely the differences in nitrogen assimilation and plant growth between the two populations. Excess Cu caused evident decreases in the shoot and root biomass and root/shoot biomass ratio in HA population while no significant changes happened in TLS population. In addition, in HA population, excess Cu also induced apparent declines in activities of nitrate reductase (NR, EC 1.6.6.1) and glutamine synthetase (GS, EC 6.3.1.2) in the leaves and roots as well as the contents of nitrate, ammonium and amino acids in the roots. In TLS population, excess Cu did not significantly affect the NR activities in the leaves and roots and the nitrate content in the roots, and apparently elevated the root ammonium and amino acids contents, although it also clearly reduced the GS activities in the leaves and roots. Besides, with the addition of Cu in the culture solution, the Cu contents in the leaves and roots of the two populations markedly increased. But this increase was significantly lower in TLS population than that in HA population; the fact might be partly responsible for the relative stabilization of nitrogen assimilation in TLS population compared to that in HA population.     

Landscape configuration affects herbivore–parasitoid communities in oilseed rape

It is crucial to consider the effects of large-scale drivers on species presences and ecological interactions to understand what structures communities. In our study, we investigated how the species composition and the potential interaction networks of herbivore and parasitoid communities in oilseed rape fields are affected by agricultural landscape characteristics. Insect communities of 26 winter oilseed rape fields in southern Sweden were captured in water traps over a continuous time span of 30 ± 2 days. In total, 31% of the variation in the composition of herbivore host communities was explained by a combination of the surrounding oilseed rape area in the study year and the previous year and distance to the nearest forest. The oilseed rape area in the study year and distance to forest also explained 14% of the variation in the composition of parasitoid communities. Distance to the nearest forest together with the area of oilseed rape in the previous year explained 45% of the variation in asymmetry of interaction webs. These results indicate that several measures of landscape configuration are important both for the composition of host and parasitoid communities and also for the structure of interaction networks. Our results support the view that it is an appropriate strategy to cultivate oilseed rape in landscapes that are far away from forests, in order to minimize recolonization by pest species and at the same time to attract parasitoid species from the open landscape.     

Wood characteristics of Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz and Gray native to Costa Rica: their significance for wood utilization

Due to over-exploitation in the past, native conifer species in many tropical countries are hardly available anymore for wood utilization. In the last decades Costa Rica has undertaken considerable efforts to study the silvicultural characteristics of the native species of the family Podocarpaceae, in particular Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz and Gray, in order to evaluate its suitability for cultivation in mixed plantations with preference for native species. However, sufficient information on the structural, chemical and physical characteristics of the wood of this species are not available. This investigation reports on selected wood characteristics of old-growth trees from the Cordillera de Talamanca (approximately 2,700 m a.s.l.), Costa Rica. Tracheids occupy 93% of total volume; average tracheid length is 4 mm, wall thickness ranges 2.5–4.5 (–6.5) μm throughout the annual increment. Lignin content is between 33.6 and 34.7% excluding any lignin-like compounds. Cellular UV microspectrophotometry reveals that the compound middle lamella (CML) and S2 layer are characterized by a higher absorbance than is commonly observed in e.g. Pinaceae, and with a distinct gradient from S1 to S3. The carbohydrate (cellulose and hemicelluloses) composition reflects the typical proportions as found in other conifers. A low content of organic extractives explains the only moderate (white rot) to low (brown rot) natural durability of the heartwood against wood destroying fungi. The wood density (12% mc) ranges 0.5–0.68 g cm^-3; compression strength (44±2.38 MPa) and corresponding modulus of elasticity (8,600±1,720 MPa) indicate good elastomechanical properties. Accordingly, the wood is recommended for multiple indoor enduses. For exterior applications, effective protective measures and/or preservative treatment are required. Dedicated to Prof. Dr. Dr. h.c. mult. Walter Liese on the occasion of his 80th birthday     

PHENIPS—A comprehensive phenology model of Ips typographus (L.) (Col., Scolytinae) as a tool for hazard rating of bark beetle infestation

We developed the model PHENIPS for spatial and temporal simulation of the seasonal development of Ips typographus at the Kalkalpen National Park in Austria. The model is based on a digital elevation model used for interpolation of temperature and solar radiation to calculate the microclimatic conditions (bark temperature) for the beetles’ development. Additionally, the beetles’ phenology at Kalkalpen National Park was monitored along with air and bark temperature measurements. The onset of host tree infestation in spring was estimated using a lower threshold of 16.5 °C for flight activity and a mean thermal sum of 140 degree-days (dd) from beginning of April 1st onward. Rate of brood development was calculated from accumulated degree-days of hourly temperature data using upper and lower temperature thresholds of 38.9 and 8.3 °C, respectively, and a nonlinear function for calculating effective thermal sums. Re-emergence of parental beetles occurred at a time when 49.7% of the thermal sum for total development (557 dd) was reached. The model includes the discontinuance of the beetle's reproductive activity at a day length <14.5 h. The rate of successful hibernation of established broods is predicted by assessing the developmental stage of initiated generations at the beginning of the cold period. For validation we compared the timing of phenological events in the field with predicted events using both, hourly recorded data at trap trees in the terrain and generated daily topoclimatic data. Using topoclimatic data, the onset of infestation was predicted with a mean absolute error of 1.3 days. The observed onset of emergence of filial beetles in the field was estimated with a mean error of 39 dd. Our PHENIPS explicitly considers the strong effects of regional topography and stand conditions on local air and bark temperature and can be used for precise monitoring of the actual state of bark beetle development at the specific stand/tree level. Using topoclimatic data, PHENIPS simulates the maximum number of generations which is necessary to assess the potential impact of bark beetle outbreaks at regional scale. Further applications of PHENIPS for site-specific hazard rating of bark beetle infestation are discussed.     

Untersuchungen über das Auftreten der Erreger der Holländischen Ulmenwelke in Österreich

Zusammenfassung Das Vorkommen der Erreger des Ulmensterbens in ?sterreich wurde in den neunziger Jahren des vorigen Jahrhunderts untersucht. Von insgesamt 174 Isolaten, die zwischen 1993 und 1997 in verschiedenen Teilen ?sterreichs gesammelt worden waren, konnten 150 aufgrund ihrer Wachstumsrate bei 20 °C und 33 °C sowie der Morphologie der Kultur auf Oxoid-Malzextraktagar der aggressiven ArtO. novo-ulmi zugeordnet werden. Die weniger aggressive ArtO. ulmi wurde kein einziges Mal nachgewiesen und kommt vermutlich in ?sterreich nicht mehr vor. Ein Isolat wies eine einzigartige Kulturmorphologie auf, die weder der vonO. ulmi noch jener vonO. novo-ulmi entsprach. Dieses Isolat ist m?glicherweise durch Hybridisierung vonO. ulmi undO. novo-ulmi entstanden. Ein Teil (<14 %) der Isolate ist aufgrund ungünstiger Bedingungen w?hrend der Stammhaltung degeneriert, zeigte untypisches Wachstum in Kultur und konnte daher nicht bestimmt werden.O. novo-ulmi konnte in den Bundesl?ndern Wien, Nieder- und Ober?sterreich, Burgenland, Steiermark, K?rnten und Tirol festgestellt werden und scheint in weiten Teilen des Verbreitungsgebietes der in ?sterreich heimischen Ulmenarten vorzukommen. Es ist damit zu rechnen, dassO. novo-ulmi weiterhin gro?e Sch?den in Mitteleuropa verursachen wird und früher oder sp?ter auch in Gebiete und Waldbest?nde vordringen wird, in denen bisher geringe oder keine Sch?den durch die Ulmenwelke aufgetreten sind.      

Variation in chromosome numbers and nuclear DNA contents in genetic resources of Lactuca L. species (Asteraceae)

Fifty accessions of 25 Lactuca species,L. serriola ×L. sativa and Mycelismuralis were analyzed for chromosome number and relative DNA amountvariation. In the majority of Lactuca species studiedchromosome counts, as earlier reported (n = 8, 9, 17), were verified; however,for L. dregeana andL. homblei (probablyL. schweinfurthii orL. longespicata) the chromosome number(n = 9) was determined for the first time. Relative nuclear DNA content,estimated by using flow cytometry (DAPI staining), showed that 2C DNA contentranged from 2.02 pg in L.capensis to 17.96 pg inL. canadensis. Statistical and clusteranalysis of data based on relative nuclear DNA contents correspond fairly wellwith recently accepted taxonomic classification of the genusLactuca. However, the position of certain species as wellas clarification of taxonomic determinations of someLactuca accessions needs further examination.     

Assessment of Detoxifying Markers for Florfenicol in Rainbow Trout Liver

Florfenicol (FF) is employed in fish farms to contest or prevent bacterial infections. However, this pharmaceutical may produce reactive oxygen species that may cause biochemical changes in antibiotic-treated fish. The aim of this study was to evaluate the effect of FF on Rainbow Trout Oncorhynchus mykiss treated for 10 d with 7.5 and 15 mg/kg FF followed by a withdrawal period of 5 d. Superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, glyoxalase I and glyoxalase II, total glutathione, lactic dehydrogenase, and alkaline phosphatase were investigated in the livers of treated and untreated fish. A general impairment of antioxidant enzymes and metabolic indicators was measured in FF-treated Rainbow Trout. Onset of oxidative damage may have occurred during the antibiotic treatment as a consequence of the effect of FF toxicity at mainly the highest dose. Nevertheless, the rise in levels of total glutathione and glutathione S-transferase even after the withdrawal period may shield the antibiotic-mediated oxidative processes.

Received December 22, 2015; accepted May 26, 2016 Published online October 28, 2016