Penman-Monteith模型模拟Venlo型温室黄瓜植株蒸腾

准确模拟温室作物蒸腾对于制定科学合理的灌溉制度及温室环境调控具有重要意义,该研究基于2017年秋冬季和2018年春夏季Venlo型温室黄瓜生育期内微气象数据、黄瓜生长发育指标和植株蒸腾,对Penman-Monteith(PM)模型中关键参数—冠层阻力和空气动力学阻力进行研究。通过分析黄瓜叶片孔阻力与温室内气象因子的响应关系,构建了由黄瓜有效叶面积指数及叶片孔阻力模拟冠层阻力的子模型;采用基于风速的Perrier对数法和基于温室对流类型的热传输系数法计算温室内低风速环境下的空气动力学阻力,并评价不同方法的适用性。结果表明:叶片孔阻力与太阳辐射呈指数关系(R~2=0.89),可通过观测温室内太阳辐射计算黄瓜叶片孔阻力;应用热传输系数法确定空气动力学阻力时,温室内对流类型绝大多数时间为混合对流;2种方法计算的温室内空气动力学阻力变化幅度均较小,Perrier对数法计算的春夏季和秋冬季空气动力学阻力平均值分别为388和383 s/m,热传输系数法计算的空气动力学阻力平均值分别为141和158 s/m;基于2种空气动力学阻力计算方法,PM模型模拟的植株蒸腾与实测值均具有较好的一致性,但采用Perrier对数法计算空气动力学阻力时,PM模型低估了植株蒸腾,春夏季和秋冬季拟合线斜率分别为0.87和0.91;而采用热传输系数法计算空气动力学阻力时,PM模型可更准确的模拟该地区温室黄瓜植株蒸腾,春夏季和秋冬季拟合线斜率分别为1.00和0.94,R~2分别为0.91和0.95,均方根误差分别为46.15和12.45 W/m~2。该研究结果为实现PM模型在Venlo型温室环境的准确应用提供了参考。     

Soil morphological control on saline and freshwater lake hydrogeochemistry in the Pantanal of Nhecolândia, Brazil

Joint pedological, geochemical, hydrological and geophysical investigations were performed to study the coexistence of saline and freshwater lakes in close proximity and similar climatic conditions in the Nhecolândia region, Pantanal wetlands in Brazil. The saline lakes are concentrically surrounded by green sandy loam horizons, which cause differential hydrological regimes.Mg-calcite, K-silicates, and amorphous silica precipitate in the soil cover, whereas Mg-silicates and more soluble Na-carbonates are concentrated in the topsoil along the shore of the saline lake. In saline solutions, some minor elements (As, Se) reach values above the water quality recommendations, whereas others are controlled and incorporated in solid phases (Ba, Sr). Locally, the destruction of the sandy loam horizons generates very acidic soil solution (pH ~ 3.5) through a process not yet understood. The soil distributions indicate that some freshwater lakes are former saline lakes. They are invaded by freshwater after destruction of the sandy loam green horizons, then the freshwater becomes enriched in K⁺, SO₄²⁻, Fe, Al, and a stream of minor and trace elements. The formation of these green sandy loam horizons in the saline environment and their destruction in the non-saline one emphasizes the dynamic nature of this environment.     

Evaluation of the effects of histone deacetylase inhibitors on cells from canine cancer cell lines

OBJECTIVE: To determine whether exposure of canine cancer cells to histone deacetylase (HDAC) inhibitors S(+)-N-hydroxy-4-(3-methyl-2-phenyl-butyrylamino)benzamide (OSU-HDAC42) or suberoylanilide hydroxamic acid (SAHA) results in increased histone acetylation and decreased cell viability and whether any changes in viability involve induction of apoptosis or alterations in progression of the cell cycle. Sample POPULATION: 9 canine cancer cell lines. PROCEDURES: Cells from 9 canine cancer cell lines were treated with dimethyl sulfoxide vehicle, OSU-HDAC42, or SAHA, then assays of cell viability were performed. Histone acetylation was assessed by use of western blot analysis. Apoptosis was assessed via ELISA to detect fragmentation of cytoplasmic nucleosomal DNA and western blot analysis to detect cleavage of caspase 3. Cell cycle analysis was performed by use of propidium iodide staining and flow cytometry. RESULTS-Concentrations of OSU-HDAC42 and SAHA required to achieve 50% inhibition of cell viability (IC(50)) were reached in cells of 6 and 4 canine cancer cell lines, respectively, and ranged from approximately 0.4 to 1.3 microM for OSU-HDAC42 and 0.6 to 4.8 microM for SAHA. Cells from T-cell lymphoma, mast cell tumor, osteosarcoma, and histiocytic sarcoma lines were most sensitive to HDAC inhibition, with IC(50)s of < 1 microM for OSU-HDAC42 and < 5 microM for SAHA. Induction of apoptosis was indicated via cleavage of caspase 3 and increases in cytoplasmic nucleosomes and the subG(1) cell population. CONCLUSIONS AND CLINICAL RELEVANCE: Micromolar concentrations of HDAC inhibitors OSU-HDAC42 and SAHA induced histone acetylation, cytotoxicity, and apoptosis in canine cancer cells. In general, OSU-HDAC42 was more potent than SAHA.     

Ungulate Herbivory Is Correlated with High Aspen Suckering Density but Reductions in Aspen Growth Rates and Recruitment

Aspen is a foundation species that provides vital habitat for hundreds of plant and animal species. However, changing ungulate herbivory regimes may be altering recruitment success and resilience of aspen forests. The objective of this observational study was to quantify the impacts of ungulate herbivory on aspen recruitment potential. We sampled 36 aspen dominant stands on the Fishlake National Forest in Utah for browse of apical meristems, suckering density (< 180 cm in height), and recruitment density (≥ 180 cm). Our analysis indicated that for each 10% of apical meristems browsed, annual vertical and radial growth rates and recruitment density were reduced by 1.2 cm, 0.02 mm, and 17 ha^? 1, respectively. In contrast, aspen suckering density increased by 1 230 suckers ha^? 1, with each 10% browse of apical meristems. This suggests that ungulates contribute to aspen suckers persisting in the understory for longer periods and may alter recruitment success of aspen stands. Aspen that were under high ungulate browse pressure were associated with lower growth rates and persisted for twice as long in the understory. For example, a 5-yr-old sucker was predicted to be 115 cm without browse of apical meristems and 60 cm with 100% browse of apical meristems. Further, aspens of the same height with 100% browse of apical meristems were nearly 4 yr older on average than aspens with no evidence of browse of apical meristems. Approximately 34% of aspen suckers had persisted in the understory < 100 cm for ≥ 6 yr, and 7% of suckers had persisted in the understory for ≥ 10 yr. Our results suggest that high rates of meristem removal are correlated with increased aspen suckering yet reduced aspen growth and recruitment.     

Northern Bobwhite (Colinus virginianus) Space Use Minimally Affected by Oil and Gas Development

Despite the fact that the northern bobwhite (Colinus virginianus Linnaeus; hereafter, bobwhite) is one of the most well-studied and widely distributed wildlife species in North America, we know little about how bobwhite respond to oil and gas infrastructure. We investigated the impacts of oil and gas development on space use of bobwhite using a multiseason approach. We captured and monitored bobwhite in the breeding season (1 April–30 September, n = 135 individuals) and nonbreeding season (1 October–31 March, n = 30 coveys) and modeled their habitat selection in a resource-utilization function (third order, within home range selection) and resource-selection function (second order, home range selection) format. Generally, energy infrastructure effects on bobwhite were neutral, but breeding season bobwhite did select for areas near low-traffic roads (β = ? 0.31 ± 0.15 SE). In the nonbreeding season, coveys selected for areas within their home range with a limited viewshed (i.e., areas with limited visibility of anthropogenic structures; β = ? 0.03 ± 0.02 SE). Selection differed between sexes for well pads (t = ? 2.12, P = 0.04) but was otherwise similar. At the level of home range selection, bobwhite exhibited a preference for areas with a low density of oil and gas wells and a high density of low-traffic roads during both the breeding and nonbreeding seasons (breeding: β_well = ? 0.14 ± 0.02, β_road = 0.26 ± 0.27; nonbreeding: β_well = ? 0.08 ± 0.03, β_road = 0.16 ± 0.03). As a generalist species, bobwhite appear to be largely tolerant of energy infrastructure and associated disturbances at moderate levels of development but may be sensitive to high densities of oil and gas pads.     

Reproductive seasonality in Saanen goats kept under tropical conditions

Tropical Animal Health and Production - This study aimed to verify the reproductive seasonality in Saanen goats from distinct parity orders (nulliparous, primiparous, and pluriparous) throughout an...     

So much for the city: Urban–rural song variation in a widespread Asiatic songbird

Song plays a fundamental role in intraspecific communication in songbirds. The temporal and structural components of songs can vary in different habitats. These include urban habitats where anthropogenic sounds and alteration of habitat structure can significantly affect songbird vocal behavior. Urban–rural variations in song complexity, song length and syllable rate are not fully understood. In this study, using the oriental magpie‐robin (Copsychus saularis) as a model, we investigated urban–rural variation in song complexity, song length, syllable rate, syllable length and inter‐syllable interval. Comparing urban and rural songs from 7 countries across its natural Asiatic range (Bangladesh, India, Malaysia, Nepal, Singapore, Sri Lanka and Thailand), we found no significant differences in oriental magpie‐robin song complexity. However, we found significant differences in temporal song variables between urban and rural sites. Longer songs and inter‐syllable intervals in addition to slower syllable rates within urban sites contributed the most to this variance. This indicates that the urban environment may have driven production of longer and slower songs to maximize efficient transmission of important song information in urban habitats.