Changes in agricultural land use can explain population decline in a ladybeetle species in the Czech Republic: evidence from a process-based spatially explicit model

Changes in land use affect species interactions and population dynamics by modifying the spatial template of trophic interaction and the availability of resources in time and space. We developed a process-based spatially explicit model for evaluating the effects of land use on species viability by modelling foraging performance and energy sequestration in a stage structured, three-trophic population model. The model is parameterized with realistic parameters for a ladybeetle–aphid–host plant interaction, and is run in four realistic landscapes in the Czech Republic. We analysed whether changes in crop selection and fertilizer input could explain the dramatic and unexplained decline in abundance of the ladybeetle Coccinella septempunctata in the Czech Republic from 1978 to 2005. The results indicate that a major reduction in fertilizer input after the transition to a market economy, resulting in lower aphid population densities in cereal crops and negatively affecting energy sequestration, survival and reproduction of ladybeetles, provides a sufficient explanation for the observed population decline. Simulations further indicated that the population viability of C. septempunctata is highly dependent on availability of aphid prey in crops, in particular cereal, which serves as their major reproduction habitat. The results demonstrate how the abundance of naturally occurring predators, which are instrumental for biological pest control, depends upon the spatial resource template that are provided at the landscape scale.     

渭北旱塬苹果园土壤水分环境效应

塬面苹果园、农田和其它主要土地利用方式的比较研究表明,苹果园的水分环境效应表现为土壤高入渗率、降雨低产流率和强烈的蒸腾耗水作用形成的土壤低湿层,使土壤水库对干旱的调节作用丧失,导致苹果产量随年际降雨呈现较大波动。随着苹果种植面积的扩大,这种水分环境效应将加强土壤、植物、大气间的水分小循环,削弱降雨转化为地表水和地下水的比例,最终影响区域水资源的数量和果业的持续发展。     

黄土高原是我国优质苹果核心产区之我见

黄土高原是世界上面积最大,土层最厚、最为洁净的一片黄土地,是世界苹果的最佳优生区,发展潜力巨大。分析了黄土高原建立优质苹果核心产区的自然条件和产业现状,提出了黄土高原建立我国优质苹果核心产区的必要性、可行性,同时对发展前景进行了分析,并提出了发展建议,以促进黄土高原优质苹果核心产区建设。     

花椰菜中器官早期发育调控相关的miRNA(Bra-miR07)的克隆及功能研究

在前期通过高通量小RNA测序获得若干在花椰菜器官早期发育过程中呈现差异表达的未知功能miRNA基础上,重点对其中1个在花椰菜下胚轴和子叶中表现为显著差异表达的miRNA(命名为Bra-miR07)进行克隆鉴定及功能分析。研究表明,Bra-miR07前体序列全长为270 bp,可形成稳定的二级发夹结构。Bra-miR07在花椰菜子叶中呈现显著高表达。进一步构建了Bra-miR07的过表达载体并采用浸花法转化拟南芥,获得Bra-miR07过表达的转基因拟南芥株系。表型分析显示,Bra-miR07过表达可显著影响拟南芥植株生长。与野生型相比,过表达Bra-miR07株系表现为生长缓慢,植株矮小,育性降低等发育受阻特征。因此,上述结果预示着Bra-miR07可能也在花椰菜器官发育过程中发挥重要作用。     

Errors in greenhouse forcing and soil carbon sequestration estimates in freshwater wetlands: a comment on Mitsch et al. (2013)

Radiative forcing feedbacks from wetlands have been an important component of past climate change and will likely be so in the future, so accurately assessing the carbon (C) and radiative balances of wetlands remains an important research priority. This commentary shows that the paper by Mitsch et al. (Landscape Ecol 28:583–597, 2013) seriously underestimated the radiative forcing effect of methane (CH₄) emissions and overestimated soil C sequestration in freshwater wetlands. The model that they used is flawed in double counting the atmospheric decay of CH₄ and incorporating a single 100 year CH₄ global warming potential. They also used a small number of sites and short-term soil dating that resulted in unrealistically high soil C sequestration rates, ignoring decay of the entire soil C pool and allochthonous inputs of C. They calculated the radiative balance instead of the radiative forcing of natural wetlands, making their calculations irrelevant to anthropogenic climate change. Irrespective of the radiative forcing of wetlands, they provide essential ecosystem services that are important to protect.     

黄土高原苹果树各生育期需水特征研究

【目的】准确界定苹果树在各个生育期的需水量及需水特征的季节性变化是指导果园节水灌溉的重要依据。【方法】利用热扩散树干液流测定技术,连续2年监测了旱作果园苹果树(盛果期)的树干液流速率,计算了单株的耗水强度,并与同步观测的叶面积指数、物候特征进行关联分析。【结果】2017、2018年苹果树年耗水量分别为295.5 mm、215.3 mm,分别占同期降水量的88%和58%。在整个年生育周期中,果实膨大期耗水量最多,占果树整个生育期耗水总量的51%(2017年)和41%(2018年),其次依次为果实成熟期、幼果形成期、花期、萌芽期、落叶期和休眠期,不同生育期果树的耗水量与同期降水量具有相似的季节变化趋势。在萌芽期,果树耗水强度快速上升,到果实膨大期时最高可达2.17 mm·d^-1;之后逐渐下降,在落叶期时耗水强度最高值为1.19 mm·d^-1;休眠期树液仍有流动,此阶段的耗水量占年蒸腾总量的5%,日蒸腾强度最高为0.53 mm·d^-1。冠层叶面积指数(LAI)的季节变化表现为从4月初展叶开始快速增加,到5月上旬达到3.2,日增速平均为0.07;之后LAI基本维持不变,日增速仅为前期的1%,最高值为3.4。在11月中旬左右遇到大风天气后快速落叶,LAI在数天内降至零。【结论】苹果树在不同生育期的需水特征有明显的差异,且与叶面积指数的季节变化并不完全同步,需结合不同生育期的水分需求特征开展合理的灌溉、控水等管理措施。     

黄土高原富士苹果叶片矿质养分与果实品质相关性分析

2012和2013年,对黄土高原12个主产区108个典型富士苹果园叶片养分和果实品质进行调查分析,应用典型相关分析方法,筛选影响果实品质因子的主要叶片养分因子,求解富士苹果优质的叶片养分含量优化方案,指出被调查果园叶片养分存在的问题。研究结果表明：黄土高原富士苹果品质整体优良,但果实硬度偏低,可滴定酸含量变异稍大。典型相关分析获得了影响苹果品质的主要叶片养分因子,单果质量为：钾 > 磷 > 镁 > 铁 > 钙;果实硬度为：镁 > 钾 > 磷 > 钙 > 铁;果实可溶性固形物含量为：镁 > 钾 > 磷 > 锌 > 钙;果实可滴定酸含量为镁 > 钾 > 氮 > 锌;果形指数的大小顺序为镁 > 钾 > 磷 > 铁 > 钙。线性规划求解出富士苹果优质的叶片养分含量优化方案为：全氮21.5 ~ 26.6 g ? kg-1、全磷1.18 ~ 1.86 g ? kg-1、全钾5.5 ~ 11.6 g ? kg-1、全钙13.6 ~ 26.1 g ? kg-1、全镁4.8 g ? kg-1、全锌15.0 ~ 75.0 mg ? kg-1、全铁100.0 ~ 180.0 mg ? kg-1,在优化条件下苹果单果质量可以达到382.5 g、果实硬度8.59 kg ? cm-2、可溶性固形物含量19.11%、可滴定酸含量0.157%、果形指数0.93。被调查的果园叶片全磷、全钾、全钙和全铁含量均较高,全氮和全锌含量相对适宜,合理施肥,平衡树体营养,防止旺长是其今后树体养分管理的关键。     

杏树受嗜果刀孢菌侵染后叶片内苯丙氨酸解氨酶活性的变化

初步研究了杏树叶片受嗜果刀孢菌Ｃｌａｓｔｅｒｏｓｐｏｒｉｕｍ　ｃａｒｐｏｐｈｉｌｕｍ（Ｌｅｗ）Ａｄｅｒｈ．侵染后苯丙氨酸解氨酶（ＰＡＬ）活性的变化,结果表明：接种后抗病品种苯丙酸类代谢被激活的程度高。李光杏（高抗）在接种后１２ ｈ与８４ ｈ出现两个酶活性高峰,张公园杏（中抗）在接种后６０ ｈ ＰＡＬ活性达到最高,兰州大接杏（感病）在接种后８４ｈ才趋于活性高峰。供试品种只有李光杏与对照达到差异显著（ａ＝ ０．０１）,表明高抗品种酶活性高峰出现得早,升高幅度大。     

基于~(15)N的‘库尔勒香梨’园土壤N_2O排放特征

【目的】N_2O作为重要的温室气体,其潜在增温作用约为CO2的190～270倍,为准确掌握源自肥料的N_2O损失状况。【方法】以6年生‘库尔勒香梨’园土壤为研究对象,采用~(15)N示踪技术,密闭式静态箱-气相色谱法对梨园土壤N_2O排放通量、累积量和Ndff值(~(15)N尿素对土壤氮素气态损失的贡献率)进行监测与分析。【结果】施肥、灌溉及温度均会影响梨园土壤N_2O排放通量、累积量及Ndff值。施肥后N_2O排通量、累积量和Ndff值,在施基肥和追施肥处理的4 d后均达到峰值;土壤N_2O排放量在灌水时期明显增加,且土壤N_2O排放通量表现为下午(16:00—20:00)中午(12:00—16:00)上午(8:00—12:00)夜间(20:00—8:00),土壤N_2O累积量表现为夜间(20:00—8:00)下午(16:00—20:00)中午(12:00—16:00)上午(8:00—12:00);土壤N_2O排放与土壤温度、土壤含水量之间均呈显著正相关(p 0.001)。~(15)N尿素贡献的~(15)N_2O的Ndff值变化表现为下午(16:00—20:00)中午(12:00—16:00)上午(8:00—12:00)夜间(20:00—8:00)。源于土壤原有氮素的N_2O排放量为0.893 3 g·plant-1,占N_2O总损失量的87.43%;而源自肥料的N_2O损失量为0.1284 g·plant-1,仅占总损失量的12.57%。【结论】‘库尔勒香梨’果园N_2O排放主要源于土壤原有氮素的N_2O排放。     

Changes in the contents of phenolic substances,phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) accompanying chilling-injury of eggplant fruit

The mechanism of browning, which is a typical chilling-injury of eggplant fruit (Solanum melongena L.), was investigated by determining the changes of phenolic substances, phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) either during storage at 1°C or after exposing fruit to low temperature for various periods.Chlorogenic acid and its isomer, the main substrates for browning, were isolated from eggplants by column and paper chromatography. R_f values and various color reactions of the above acids were compared with those of authentic chlorogenic acid.After 2 days of cold storage at 1°C, when browning was initiated, chlorogenic acid content decreased to less than half that of the initial day, rose to a maximum after 4 days, and then decreased rapidly.PAL activity increased to a peak after 2 days at 1°C, then decreased over 10 days as browning increased. TAL activity also increased after transfer from 1°C to 20°C.It is suggested that rapid turn-over of chlorogenic acid occurs in the early stage of cold storage of eggplant fruit, and development of browning is closely related to chlorogenic acid, PAL and TAL.     

Changes of liver sinusoidal endothelial cells and basement membrane in early stage of liver fibrosis induced by carbon tetrachloride in rats

AIM：To explore the development of hepatic sinusoidal capillarization in the early stage of liver fibrosis induced by carbon tetrachloride (CCl4) in rats. METHODS：Clean SD rats were randomly divided into normal control group (group N, n=6) and liver fibrotic model group (group M, n=32). The rats in group N were intraperitoneal injected with saline and the rats in group M were intraperitoneal injected with CCl4 (2 mL/kg, twice a week for 4 weeks). At the end of the 3rd day and the 1st, 2nd and 4th weeks, all rats were killed and then the samples were collected. The pathological changes in the livers were observed by HE staining and Masson straining. The development of hepatic sinusoidal capillarization was observed by transmission electron microscopy (TEM) and immunohistochemical staining. The cell surface expression of vascular endothelium-associated marker CD31, collagen type Ⅳ (Col IV) and laminin (LN) was determined. RESULTS：HE and Masson staining showed the formation of liver fibrosis after treatment with CCl4 for 4 weeks. TEM showed that the fenestrate diameter of liver sinusoidal endothelial cells (LSECs) grew down, the fenestrate numbers of LSECs were decreased along with the development of liver fibrosis, and the consecutive basement membrane was formed at the end of the experiment. The expression of CD31 was significantly increased along with the development of defenestration, and the expression of Col IV and LN was significantly increased after the treatment with CCl4 for 2 weeks and 4 weeks, respectively. CONCLUSION：The typical hepatic sinusoidal capillarization was detected in the early stage of liver fibrosis, and the deposition of LN in the liver sinusoidal walls was the mainly factor of formation of the consecutive basement membrane.     

低磷胁迫下平邑甜茶根构型与磷吸收特性的变化

为揭示苹果适应低磷胁迫的机制,以平邑甜茶[Malus hupehensis （Pamp）Rehd.]为材料,采用水培方式研究了缺磷和复磷条件下根系磷吸收和根构型参数的变化。结果显示,平邑甜茶幼苗在缺磷营养液中培养120 h期间,根系磷最大吸收速率始终高于对照,并趋向一个较稳定的差值;缺磷处理最初12 h内根系磷吸收米氏常数Km值提高,但72～120 h明显下降。缺磷处理的平邑甜茶幼苗转到完全营养液中培养12～120 h,根系对磷的转运效率影响不大,而与磷的亲和力下降,并逐渐恢复到正常状态。平邑甜茶幼苗在缺磷条件下培养至11 d时,一级侧根总长度低于对照,但在17～26 d时,一级侧根总长度明显提高。结果表明,平邑甜茶在短期内主要通过磷吸收动力学的变化来适应缺磷胁迫,较长时期则通过根构型的变化来适应。     

芥蓝生长发育过程中生理生化指标的变化

对芥蓝生长发育过程中生理生化指标的变化结果表明,丙二醛（MDA）、游离脯氨酸（Pro）和维生素C（VC）的含量及过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化物歧化酶（SOD）的活性具有明显的阶段特异性。植株体内较高的VC与可溶性蛋白质含量和CAT、POD、SOD活性以及较低的MDA含量有利于花芽分化和菜薹形成。     

油红梨（Pyrus ussuriensis）果实后熟过程中香气成分的变化

通过顶空固相微萃取结合气相色谱质谱联用技术分析油红梨果实后熟不同时期挥发性组分。后熟0d、5d及10d时分别检测出11、26和33种挥发性成分,主要为酯类、醛类、醇类及萜类物质。各种挥发性物质在不同的后熟时期种类及绝对含量均为升高的趋势,尤其是酯类组分的增加;35种挥发性组分中共检测出7种特征香气组分,分别为己醛、E-...     

Changes of apoptosis and cell cycle of HSC in rat hepatic fibrosis by treatment with traditional Chinese medicine prescription (Dan-Shao-Hua-Xian)

AIM: To investigate the effect of a Chinese medicime, Dan-Shao-Hua-Xian capsule, on liver fibrosis induced by CCl4 by observation of apoptosis and cell cycle variation in the liver cells. METHODS: Animal models were produced through eight-week treatment of the rats with CCl4, alcohol and diet of high fat/low proteins, and then administration of Dan-Shao-Hua-Xian to the rats (1 g/kg) via stomach-tube－pouring for eight weeks was performed. Liver index, serum hyaluronic acid (HA) and glutamate pyruvate transaminase (ALT) were measured and hydroxyproline (Hyp) content in urine were determined. The extent of the liver fibrosis was observed under light microscope and apoptosis and cell cycle were also examined by cytometry between the two groups. RESULTS: Compared to the liver fibrosis group, the liver index, serum HA, ALT in the treatment group decreased, the development of liver fibrosis delayed, the urine Hyp and the number of apoptosed cells and the ratio of G0/G1 cells increased, as well as the S phase cells decreased, yet unable to return to normal. All those changes detected were statistically significant. CONCLUSIONS: The Dan-Shao-Hua-Xian is effective in treating the CCl4-induced liver fibrosis in rats partly by virtue of inhibition of the growth of hepatic stellate cells and induction of apoptosis.     

Virus-induced gene silencing as a tool for functional analyses in the emerging model plant Aquilegia (columbine, Ranunculaceae)

Background  

There is considerable interest in rapid assays or screening systems for assigning gene function. However, analysis of gene function in the flowers of some species is restricted due to the difficulty of producing stably transformed transgenic plants. As a result, experimental approaches based on transient gene expression assays are frequently used. Biolistics has long been used for transient over-expression of genes of interest, but has not been exploited for gene silencing studies. Agrobacterium-infiltration has also been used, but the focus primarily has been on the transient transformation of leaf tissue.     

银杏雌花芽分化过程中内源激素含量的变化

银杏雌花芽形态分化前的５月初,ＺＴ,ＡＢＡ处于高峰,ｉＰＡｓ的高峰晚２０ｄ出现;６月份,随着形态分化开始,ＺＴ,ｉＰＡＳ和ＡＢＡ的含量下降并维持低水平;１１月开始落叶时ＡＢＡ含量迅速上升。ＩＡＡ在５月中旬出现峰值,进入６月形态分化开始后则在略低水平上波动,９月底开始缓慢下降。