Life history and population dynamics of the Japanese Yam,Dioscorea japonica Thunb.

The adaptive significance of the emergence mode ofDioscorea japonica was studied with respect to initial plant size (seed, bulbil and tuber) and light intensity, using mathematical simulation based on Yokoi's (1976) model. Under 1.5% full sunlight conditions, plants emerging with only one leaf did not develop a shoot system throughout the growing period (Hori and Oshima, 1986). Simulation indicated that, for this species of plant under poor productive conditions, the optimal time for switch-over from the vegetative to reproductive growth phase to maximize the tuber weight at the end of the growing period, occurred immediately following the start of autotrophic growth. By means of shoot growth patterns, small and large size plants acquired the ability of shade tolerance and shade avoidance, respectively. Further, the life history ofD. japonica could be expressed as a flow chart based on plant size and light intensity data.     

Cell bathing medium as a target for non thermal effect of millimeter waves

Non thermal (NT) effect of direct radiation 4 Hz-modulated 90–160 GHz of Millimeter Waves (MMW) and preliminary MMW-treated physiological solution (PS) influence were studied on snail isolated neuron, rat's brain tissue hydration and skin penetration. It was shown that the 4 Hz-modulated low intensity 90–160 GHz MMW direct radiation and MMW-treated PS leads to on single neuron shrinkage, skin and brain tissue dehydration. On the basis of obtained data it was suggested that the cell bathing aqua medium serve as a target through which the NT effect of MMW on cell hydration is realized. The MMW-induced brain tissue dehydration can considering as consequence of MMW-induced skin water structural changes leading to unknown messenger formation able to modulate the brain cell hydration. The extrasensitivity of cell hydration to low intensity of MMW radiation allow to recommend cell hydration as a cellular marker for estimation of the NT biological effect of MMW on cells and organisms.     

我院2015-2018年度抗菌药物的使用强度与鲍曼不动杆菌的耐药性的关系研究

摘要 目的：分析我院2015-2018年度抗菌药物的使用强度与鲍曼不动杆菌的耐药性的关系。方法：统计2015年1月～2018年12月北京中医医院顺义医院抗菌药物的应用情况以及鲍曼不动杆菌的耐药性。鲍曼不动杆菌的耐药性资料来源于检验科临床送检的伤口分泌物、痰液、血液、尿液等病原学标本。结果：2015年～2018年,共分离到菌株13246株,其中分离到鲍曼不动杆菌株1927株,分离率为14.55 %。其中 2015 年的分离率为3.11 %,2016年的分离率为4.51 %,2017 年的分离率为5.15 %,2018 年的分离率为2.11 %;鲍曼不动杆菌标本分离率最高的为痰液,占78.83 %,其次为伤口分泌物,占12.51 %,尿液标本占5.81 %,血液标本占2.85 %;鲍曼不动杆菌在我院所有致病菌中的排序均为第一位或者第二位;2015年～2018年抗菌药物的使用强度逐年升高,2018年有所降低;2015年～2018年鲍曼不动杆菌对哌拉西林钠他唑巴坦钠、美洛培南以及亚胺培南的耐药率均逐年升高,2018年有所降低;哌拉西林钠他唑巴坦钠、美洛培南以及亚胺培南的耐药性与抗菌药物使用强度之间具有明显的相关性（P<0.05）。结论：哌拉西林钠他唑巴坦钠、美洛培南以及亚胺培南的使用,是造成鲍曼不动杆菌耐药的重要原因之一,临床应加以重视。     

柑橘木虱成虫趋光行为反应

柑橘木虱Diaphorina citri Kuwayama是柑橘黄龙病(huanglongbing,HLB)的重要传播媒介。为了利用灯光诱控技术防治柑橘木虱,本实验于室内条件下研究柑橘木虱对波长为360 nm、400 nm、440 nm、480 nm、520 nm、560 nm和600 nm的LED光源和不同光照强度趋光行为反应。结果表明:柑橘木虱对7种单色光都有正趋向性。其中雌雄混合存在时对400 nm的紫光趋向性最强,其次是560 nm的绿光;单独处理时,雌成虫对400 nm的紫光趋性最强,其次是520 nm的绿光,雄成虫则是对520 nm的绿光趋性最强,其次是400 nm的紫光。在200μw/cm 2到1000μw/cm 2的光照强度范围内,随着光照强度的增大,柑橘木虱雄成虫趋光行为逐渐增强,在光照强度为1000μw/cm 2时趋光行为最强,但雌成虫趋光行为变化不明显。该研究表明:柑橘木虱雌雄成虫具有明显的正趋光性,且对光谱和光强的反应存在差异。这一结果可为柑橘木虱田间的灯光诱控提供实验依据。     

Comparison of biodiversity and ground cover between a commercial rotationally grazed property and an adjacent nature reserve in semi‐arid rangeland

Continuous livestock grazing can have negative effects on biodiversity and landscape function in arid and semi‐arid rangelands. Alternative grazing management practices, such as rotational grazing, may be a viable option for broad‐scale biodiversity conservation and sustainable pastoral management. This study compared ground cover, plant species composition and floristic and functional diversity along gradients of grazing intensity between a pastoral property rotationally grazed by goats and an adjacent nature reserve (ungrazed by commercial livestock) in semi‐arid south‐eastern Australia. Understorey plant species composition differed significantly between the rotationally grazed property and the nature reserve, with a greater proportion and frequency of palatable species recorded in the nature reserve. Understorey plant species richness, diversity, functional biodiversity measures and ground cover declined with increasing grazing pressure close to water points under commercial rotational grazing management. However, at a whole‐paddock scale, there were few differences in plant biodiversity and ground cover between the rotationally grazed property and the nature reserve, despite differences in overall plant species composition. Flexible, adaptive, rotational grazing should be investigated further for its potential to achieve both socio‐economic and biodiversity conservation outcomes in semi‐arid rangelands to complement existing conservation reserves.     

Effects of artificial light on the larvae of the firefly Lamprigera sp. in an urban city park,Peninsular Malaysia

Firefly populations are threatened globally by habitat alteration, pesticide use, and anthropogenic sources of light. Lamprigera fireflies were recently reported at an urban city park in Kuala Lumpur, Peninsular Malaysia. Here we report on the responses of Lamprigera larvae to artificial light from street lamps on paved park trails. Larvae were located farther from artificial light sources when street lamps were illuminated than when they were not, and mostly where light intensities were lowest, off park trails. Larvae that were located within the direct field of illumination tended to be immobile, whereas, when street lamps were turned off, they actively travelled paved trails. Larvae positioned directly in the path of downwelling light from street lamps at dusk may therefore experience an effectively longer diurnal period, limited time for active foraging, and greater exposure to pedestrian traffic.     

雪灾干扰后林冠开阔度对黄心树幼苗更新的影响

幼苗更新是森林更新的关键过程,而林窗对于植物幼苗更新、生长及最终存活具有重要影响。极端气候事件会使森林在短时间内形成大量林窗,从而显著影响林内幼苗更新和存活。本研究以2015年雪灾后云南省哀牢山中山湿性常绿阔叶林优势种黄心树(Machilus bombycina)幼苗为对象,对194个1 m×1 m样方中的幼苗生长和死亡动态进行为期4年的监测,利用线性混合模型(LMM)和广义线性混合模型(GLMM),分析林冠开阔度对幼苗高度相对生长率、叶片相对增长率、新增率和死亡率的影响,研究了雪灾干扰后的林冠开阔度对植物幼苗更新的影响。结果表明:(1)林冠开阔度随时间推移逐渐变小(20.07%~9.97%),且速度由快到慢;(2)2015-2016年,已有幼苗高度相对生长率与林冠开阔度呈显著正相关(P<0.05),其余年份两者间无显著相关性;2016-2017年已有幼苗叶片相对增长率与林冠开阔度呈显著正相关(P<0.05),其余年份两者间无显著相关性;(3)林冠开阔度与幼苗新增率和死亡率均无显著相关性。本研究表明,雪灾后造成的林冠开阔度增加有利于黄心树幼苗生长。     

Application of leaf size and leafing intensity scaling across subtropical trees

Understanding the scaling between leaf size and leafing intensity (leaf number per stem size) is crucial for comprehending theories about the leaf costs and benefits in the leaf size–twig size spectrum. However, the scaling scope of leaf size versus leafing intensity changes along the twig leaf size variation in different leaf habit species remains elusive. Here, we hypothesize that the numerical value of scaling exponent for leaf mass versus leafing intensity in twig is governed by the minimum leaf mass versus maximum leaf mass (M _min versus M _max) and constrained to be ≤−1.0. We tested this hypothesis by analyzing the twigs of 123 species datasets compiled in the subtropical mountain forest. The standardized major axis regression (SMA) analyses showed the M _min scaled as the 1.19 power of M _max and the ‐α (−1.19) were not statistically different from the exponents of M _min versus leafing intensity in whole data. Across leaf habit groups, the M _max scaled negatively and isometrically with respect to leafing intensity. The pooled data''s scaling exponents ranged from −1.14 to −0.96 for M _min and M _max versus the leafing intensity based on stem volume (LIV). In the case of M _min and M _max versus the leafing intensity based on stem mass (LIM), the scaling exponents ranged from −1.24 to −1.04. Our hypothesis successfully predicts that the scaling relationship between leaf mass and leafing intensity is constrained to be ≤−1.0. More importantly, the lower limit to scaling of leaf mass and leafing intensity may be closely correlated with M _min versus M _max. Besides, constrained by the maximum leaf mass expansion, the broad scope range between leaf size and number may be insensitive to leaf habit groups in subtropical mountain forest.     

Seasonal trends in morpho-physiological attributes and bioactive content of Valeriana jatamansi Jones under full sunlight and shade conditions

Valeriana jatamansi Jones, an important medicinal herb of the Himalayan region, is an essential source of many therapeutic compounds and is traded/consumed in very high volume. The hypothesis of this study was that different seasons and light conditions may affect the content of medicinally valuable components with changes in the morpho-physiological attributes of the plant. Growing plants under suitable light conditions and harvesting of appropriate plant parts in optimum season is crucial for harnessing the full potential of the crop. Thus, the study was carried out to determine the seasonal response of V. jatamansi plants (genetically identical plants of same age) in terms of growth and phytochemical content under two different light conditions (full sunlight and 50% shade). During all seasons, growth parameters (plant height, leaf number, leaf area, relative water content, plant biomass) and the principle bioactive compounds (valerenic acid) were higher under shade conditions, while total flavonoids, tannins, phenolic compounds and antioxidant activities were higher under full sunlight conditions. HPLC analysis revealed that valerenic acid and most of the phenolic content were higher during summer season, especially in leaf part of the plant. The study suggested harvesting of V. jatamansi plants (especially leaf), during summer season to harness high quality raw material and to prevent loss of belowground parts. This strategy can be adopted by farmers for large scale cultivation of species.Supplementary InformationThe online version of this article contains supplementary material available at 10.1007/s12298-021-00944-0     

Association of the invasive Haemaphysalis longicornis tick with vertebrate hosts,other native tick vectors,and tick-borne pathogens in New York City,USA

Haemaphysalis longicornis, the Asian longhorned tick, is an invasive ixodid tick that has rapidly spread across the northeastern and southeastern regions of the United States since first reported in 2017. The emergence of H. longicornis presents a potential threat for livestock, wildlife, and human health as the host associations and vector potential of this invasive pest in the United States are poorly understood. Previous field data from the United States has shown that H. longicornis was not associated with natural populations of small mammals or birds, but they show a preference for medium sized mammals in laboratory experiments. Therefore, medium and large sized mammals were sampled on Staten Island, New York, United States, to determine H. longicornis host associations and vector potential for a range of human and veterinary pathogens. A total of 97 hosts were sampled and five species of tick (Amblyomma americanum, Dermacentor variabilis, H. longicornis, Ixodes scapularis, Ixodes cookei) were found feeding concurrently on these hosts. Haemaphysalis longicornis was found in the highest proportions compared with other native tick species on raccoons (55.4%), Virginia opossums (28.9%), and white-tailed deer (11.5%). Tissue, blood, and engorged larvae were tested for 17 different pathogens using a nanoscale PCR platform. Infection with five pathogens (Borrelia burgdorferi, Anaplasma phagocytophilum, Rickettsia spp., Mycoplasma haemocanis, and Bartonella spp.) was detected in host samples, but no pathogens were found in any larval samples. These results suggest that although large and medium sized mammals feed large numbers of H. longicornis ticks in the environment, there is presently a low potential for H. longicornis to acquire pathogens from these wildlife hosts.