渭干河—库车河三角洲绿洲主要作物不同生育期需水量估算

采用联合国粮农组织最新推荐的模型方法(FAO56),参照毗邻地区的灌溉试验成果和当地群众的灌水经验.对渭干河--库车河三角洲绿洲冬小麦、夏玉米和棉花等作物不同生育期的需水量及需水规律进行了分析.结果表明:①作物各生育期需水量的多少,取决于生育期的长短和需水强度;②作物需水量自西向东、自南向北增加,其空间波动与气温、风速和湿度息息相关;③若根据目前渭干河一库车河三角洲绿洲农业用水所占总水量的实际比例计算,地表水供给量完全满足作物对需水的要求.如果按国际上发展经济用水占河流总水量的比例计算,河道有效来水量只能满足作物的需水要求.若要全部考虑城镇工业用水、生活用水及农业用水,加上地表水资源的利用率较低、季节变化大,则不能完全满足作物灌溉用水,导致挤占生态用水.     

Performance and food behaviour of Brycon orbignyanus larvae submitted under food restriction

This study was carried out to evaluate the effects of feed restriction on the performance and feeding behaviour of Brycon orbignyanus. Ten‐day larvae (72.84 ± 8.61 mg) were distributed in 36 aquariums (density of 15 larvae/L) in a completely randomized design consisting of six treatments and six replicates. The treatments were determined according to the number of feed restriction days: 0, 2, 4, 6, 8 and 10 days (F0, F2, F4, F6, F8 and F10, respectively), totalling 10 days. The results for final weight, weight gain and specific growth rate were significant (p < .05), and F2 and F0 presented the highest values among all experimental groups. The adopted feeding strategies did not influence final survival (p > .05), and no cannibalism behaviour was observed in any of the treatments. F2 and F0 treatments also displayed higher swimming speed (p < .05) among the assessed groups. The time spent searching for and capturing prey was significantly lower in the F0 treatment. Muscular atrophy for the F10 group was observed, and F2 animals presented no significant difference (p > .05) in muscle fibre diameter when compared to F0. Thus, dietary restrictions can be applied as a strategy for B. orbignyanus reared in intensive laboratory systems for 2 days without compromising performance, muscle growth and feeding behaviour.     

基于PSR-EEES模型的叶尔羌河平原绿洲生态安全预警测度

为客观评价叶尔羌河平原绿洲生态安全警情,基于PSR-EEES模型构建适合研究区的指标评价体系,运用综合指数法测度1990—2016年叶尔羌河平原绿洲生态安全预警状态,并结合GM(1,1)模型预测2026—2032年区域生态安全态势。结果表明:1)1990—2016年叶尔羌河平原绿洲生态安全综合预警指数总体呈增长趋势,综合预警指数从0.255 8增加到0.551 6,生态预警状态由重警转为中警,预警指示灯由橙色变为黄色;2)GM(1,1)预测模型显示,2026—2032年研究区生态安全态势进一步好转,生态安全预警值从0.726 2上升到0.891 3,安全状态由较安全转向安全,安全等级从Ⅱ级上调为Ⅳ、Ⅴ级;3)空间上各县生态安全预警状态差异明显,研究初期西南部地区生态安全状态优于中东部地区,2016年呈现出中部高、东北-西南部低的态势。研究显示,近26年叶尔羌河平原绿洲生态环境得到了一定恢复,但绿洲内部各县生态预警状态差异明显,生态文明建设工作任重而道远。     

近50年来新疆人口时空变化特征及成因分析

人口增长包括人口的自然增长和机械增长两个方面,人口增长会对一个区域的社会经济发展产生较大的影响,而人口增长又受政治、历史、经济和自然等多因素的制约。自20世纪50年代以来,新疆人口年均增长速率2.97%,明显高于全国平均水平1.53%,属于人口快速增长地区。其原因主要是:(1)高出生率导致高人口自然增长率,从1955年至2005年的50年期间,新疆人口的平均自然增长率17.91‰,高于全国平均水平15.20‰;(2)20世纪50~60年代人口大规模迁入造成的,到1967年底,全疆迁移净增人口共257.22×104人,平均每年迁移净增人口都在15万人以上,从1968年起,人口增长完全依赖自然增长。新疆人口分布的空间变化规律总体分布趋势为西密东疏,北多南少;山区和盆地相交的山前冲洪积扇缘绿洲地带最多,盆地中心及其盆地周围山区人烟稀少。新疆人口密度明显增加,高值区的范围在不断扩大,低值区的范围在缩小。     

Sewage Sludge Usage in Agriculture: a Case Study of Its Destination in the Curitiba Metropolitan Region,Paraná, Brazil

The agricultural destination of sewage sludge promotes the return of organic matter and nutrients to the soil, prevents contamination and degradation of hydric resources, and contributes to food and fiber production. In Brazil, the Resolution of the National Environment Council (Conama 375/06) and in the State of Paraná the Resolution of the State Environment Cabinet (Sema 021/09) established criteria and procedures for agricultural use of sewage sludge seeking to avoid risk to public health and the environment. This case study attempts to present the results of the destination of the sludge generated in the Sludge Management Units (SMU) in Curitiba Metropolitan Region (CMR), State of Paraná, Brazil from 2007 to 2010. Data analysis of agronomic parameters and inorganic substances (metals) of 99 batches of sewage sludge destined for agricultural use, based on 239 agronomic projects, was performed. The comparison of the characteristics of the batches generated in anaerobic and aerobic SMUs of CMR was also conducted. During the study, 88,166 t of sludge (33,404 dry tons) were destined for 2,288 ha of agricultural areas. The sludge provided 88 % of the lime, 74 % of N, 73 % of P₂O₅, and 35 % of K₂O for fertilizing the corn, soybean, bean, oat, wheat, green manure, and in the implementation and postharvest of stone fruit trees. The 80 benefited farmers reduced expenses with fertilizers and limestone, saving an average of US$813.45 per ha.     

Chemical constituents of Morinda citrifolia fruits inhibit copper-induced low-density lipoprotein oxidation

The oxidative modification of low-density lipoprotein (LDL) plays an important role in the genesis of arteriosclerosis. The present study focused on the effects of the fruits of Morinda citrifolia on preventing arteriosclerosis. The MeOH extract and CHCl(3)-, EtOAc-, n-BuOH-, and H(2)O-soluble phases derived from the fruits of M. citrifolia were evaluated for their inhibitory activity on copper-induced LDL oxidation by the thiobarbituric acid-reactive substances (TBARS) method. The MeOH extract and EtOAc-soluble phase showed 88 and 96% inhibition, respectively. Six lignans were isolated by repeated column chromatography from the EtOAc-soluble phase. These compounds were determined by spectroscopic analysis to be 3,3'-bisdemethylpinoresinol (1), americanol A (2), americanin A (3), americanoic acid A (4), morindolin (5), and isoprincepin (6), of which 4 and 5 are novel compounds. These compounds inhibited copper-induced LDL oxidation in a dose-dependent manner. 1, 2, 5, and 6 exhibited remarkably strong activities, which were the same or better than that of the known antioxidant 2,6-di-tert-butyl-p-cresol. The IC(50) values for 1, 2, 5, and 6 were 1.057, 2.447, 2.020, and 1.362 microM, respectively. The activity of these compounds is mainly due to their number of phenolic hydroxyl groups.     

拉枝角度对中矮1号矮化中间砧库尔勒香梨光合荧光参数的影响

【目的】研究不同拉枝角度对中矮1号矮化中间砧库尔勒香梨光合及叶绿素荧光特性的影响,为矮砧密植库尔勒香梨幼树整形栽培最适宜的拉枝角度提供理论依据。【方法】以杜梨为基砧,中矮1号为中间砧木的5年生库尔勒香梨为材料,采用不同拉枝角度(40°、60°、80°、100°)4个处理,测定并分析不同拉枝角度下库尔勒香梨的光合特性和叶绿素荧光特性差异。【结果】不同拉枝角度处理下中矮1号矮化中间砧库尔勒香梨的净光合速率(P_n)日变化曲线均呈“双峰”型,存在明显的光合午休现象。随着拉枝角度的增大,库尔勒香梨的光合参数也随着增大,但当拉枝角度过大,超过80°时,树体光合作用则会受到抑制。在80°拉枝处理下,库尔勒香梨的光合参数P_n、气孔导度(G_s)、细胞间隙CO ₂浓度(C_i)和蒸腾速率(T_r)日均值均高于其他3个处理,P_n日均值最高可达10.04 μmol/(m²·s),P_n、C_i和T_r日均值与其他处理存在显著性差异,实际光化学效率(Φ_PSⅡ)、光化学淬灭系数(C_qp)、非光学淬灭系数(C_NPQ)和PSII电子传递速率(R_ET)日均值最高。【结论】库尔勒香梨在80°拉枝角度时光合作用最强,受光抑制较弱,80°拉枝角度可作为中矮1号矮化中间砧库尔勒香梨幼树整形栽培的较适宜拉枝角度。     

Quantitative trait loci conferring blast resistance in hexaploid wheat at adult plant stage

Blast disease, caused by the Magnaporthe oryzae Triticum pathotype (MoT), is a major concern for wheat production in tropical and subtropical regions. The most destructive symptoms occur in wheat spikes. Infected spikes become bleached due to partial or total sterility, producing small and wrinkled grains. High disease pressure of the disease results in significant yield losses. This study aimed to identify wheat quantitative trait loci (QTLs) conferring resistance to blast disease at the heading stage. A doubled-haploid population was developed from the cross between BRS 209 (susceptible) and CBFusarium ENT014 (resistant, carrying the 2NS translocation). A linkage map was constructed containing 5,381 molecular markers and the inclusive composite interval mapping method was employed for QTL detection. Four QTLs were mapped in response to two MoT isolates. The major QTL identified on the 2AS chromosome explained an average of 84.0% of the phenotypic variation for spike bleaching at 9 days postinoculation and reinforces the potency of the 2NS translocation. Recombination between the distal region of chromosome 2AS and the 2NS marker was found. These results could explain why some lines carrying the VENTRIUP/LN2 marker have a variable reaction to the disease. QTLs on 5B and 7B chromosomes were also identified. Two mechanisms of resistance were hypothesized: the hypersensitive response and resistance to colonization of host tissues. The KASP markers thus developed and simple sequence repeats (SSRs) allocated in QTL regions can be used in the future for the development of wheat blast-resistant cultivars.     

Spatial modelling indicates Striga seedbank density dependence on rainfall and soil traits in the savannas of northern Nigeria

Striga is one of most notorious weeds devastating crop production in the dry savannas of northern Nigeria. The weed attacks most cultivated cereals and legumes with crop losses as high as 100% when no control measure is employed. Studies conducted in the dry savannas of Nigeria indicated that Striga seedbank is strongly related to soil and climate properties. This study was conducted to model Striga hermonthica seedbank zones in the dry savannas of Nigeria based on soil and climate properties of the areas. Using multi-stage spatial sampling, 169 soil samples were collected at the centroids of 25 × 25 km grids across the study area and analysed for physico-chemical properties. The number of Striga seeds were counted from the soil samples using water elutriator and potassium bicarbonate method. Daily temperature, relative humidity and rainfall for each point were downloaded from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS). Minimum and maximum temperatures, and relative humidity were accessed from National Aeronautics and Space Administration (NASA POWER). Thresholds of various soil and climate variables for optimum concentration of Striga seedbank were analysed using boundary line analysis (BLA). From the BLA, optimum amount of rainfall for high Striga seedbank was 549 mm per annum. While temperature has a wide suitability range for Striga seedbank development. Principal component analysis was used to reduce dimensionality of the dataset into principal components (PCs). Seven PCs which explained 75.6% variation in the data were retained and used in the weighed overlay modelling (WOM). The weighted overlay map produced five distinct Striga seedbank zones; very low, low, moderate, high and very high. More than 60% of the study area had moderate to high Striga seedbanks. The zones vary mostly based on soil, climate and Striga seed count. The establishment of the optimum levels of the environmental factors at which Striga seedbank is favoured will assist in designing a more site-specific Striga management. However, for scalability purpose, adoption of the Striga zoning approach can be useful.     

Dynamics of innate immune response in Gallus domesticus using two methods of induced molting

The aim of this study was to compare the ability of laying hen abdominal macrophages during the second production cycle by using two different methods of induced molting. Two groups of Single Comb White Leghorn hens were induced to molt at the end of their first production cycle using feed restriction and ZnO supplementation. Macrophages were isolated from the abdomen and in vitro cytotoxic ability, at which point macrophage bactericidal moiety nitric oxide (NO) was recorded. Serum IgM and IgG titers against sheep red blood cells (SRBC) were determined at various stages: before molting (BM), 5% production level (5P), peak production stage (PP) and at the end of production (EP) level after fast and Zn-induced molt. Macrophages adherence percentage remained unaffected (p ≤ 0.05) during all production cycles, whereas the macrophage engulfment percentage and engulfment/cell was significantly higher (p ≤ 0.05) at PP in both fast and Zn-induced molted groups, as compared to all other studied stages. Macrophage NO production was increased (p ≤ 0.05) at PP and after SRBC and lipopolysaccrides (LPS) stimulus, when molted with ZnO supplementation. Serum total antibody titer against SRBC increased serum IgG and IgM titers during the second production cycle by Zn-induced molt. However, molting stress greatly reduced IgG and IgM production at the 5P stage. Serum Zn concentration increased with the onset of production but decreased at the EP stage irrespective of their molting regimes. Our results validate the strengthened innate and acquired immune response during the second production cycle after Zn-induced molting instead of fasting.