N-(2,4,5-三氯苯基)-2-氧代环己烷基磺酰胺对灰葡萄孢的抑制作用

研究了新型环烷基磺酰胺类化合物N-(2,4,5-三氯苯基)-2-氧代环己烷基磺酰胺(简称化合物108)对灰葡萄孢菌丝生长、孢子形成和萌发以及菌核产生等不同生育阶段的抑制作用及其对菌丝致病力和形态结构的影响。结果表明:化合物108对灰葡萄孢菌丝生长和孢子形成及孢子萌发具有明显的抑制作用,其EC50值分别为6.90、4.70和4.11μg/mL;菌核形成受到明显抑制,当药剂质量浓度达20μg/mL时,无菌核产生。经化合物108处理后的灰葡萄孢菌丝致病力下降,40μg/mL处理的菌丝致病力显著低于对照。超微结构观察结果表明,化合物108能导致灰葡萄孢菌丝萎缩、塌陷和变形,菌体细胞壁增厚、皱缩及分层。     

Stem radial CO_2 conductance affects stem respiratory CO_2 fluxes in ash and birch trees

The CO_2 released from respiring cells in woody tissues of trees can contribute to one of three fluxes:efflux to the atmosphere(E_A),internal xylem sap transport flux(F_T),and storage flux(DS).Adding those fluxes together provides an estimate of actual stem respiration(R_S).We know that the relative proportion of CO_2 in those fluxes varies greatly among tree species,but we do not yet have a clear understanding of the causes for this variation.One possible explanation is that species differ in stem radial CO_2 conductance(g_c).A high g_c would favor the E_A pathway and a low g_cwould favor the F_Tpathway.However,g_chas only been measured once in situ and only in a single tree species.We measured g_cusing two methods in stems of Fraxinus mandshurica Rupr.(ash)and Betula platyphylla Suk.(birch)trees in situ,along with R_S,E_A,F_T and DS.Stem radial CO_2 conductance was substantially greater in ash trees than in birch trees.Corresponding to that finding,in ash trees over 24 h,E_Aconstituted the entire flux of respired CO_2 ,and F_Twas negative,indicating that additional CO_2 ,probably transported from the root system via the xylem,was also diffusing into the atmosphere.In ash trees,F_T was negative over the entire 24 h,and this study represents the first time that has been reported.The addition of xylem-transported CO_2 to E_A caused E_Ato be 9% higher than the actual R_Sover the diel measurement period.Birch trees,which had lower g_c,also had a more commonly seen pattern,with E_A accounting for about 80% of the CO_2 released from local cell respiration and F_T accounting for the remainder.The inorganic carbon concentration in xylem sap was also lower in ash trees than in birch trees:2.7 versus 5.3 mmol L^-1,respectively.Our results indicate that stem CO_2 conductance could be a very useful measurement to help explain differences among species in the proportion of respired CO_2 that remains in the xylem or diffuses into the atmosphere.     

金银花贮藏过程中绿原酸含量的高光谱无损检测模型研究

绿原酸(chlorogenicacid,CGA)是评价金银花品质的重要指标。为了实现金银花贮藏期间CGA含量变化的快速有效检测,该文采集了500个不同贮藏时间(0～20d)的金银花高光谱图像,构建CGA含量的高光谱检测模型。为了提高模型性能,采用savizky-golay卷积平滑(SG),移动窗口平滑(moving average),标准正态变量(standard normal variable,SNV),基线校正(baseline correction,BC),多元散射校正(multiplicative scatter correction,MSC),正交信号校正(orthogonal signal correction,OSC)6种预处理方法并建立偏最小二乘回归(partial least squares regression,PLSR)模型,确定SNV方法为最佳预处理方法,其预测集的R2为0.976 6,RMSE为0.271 1%。为了简化校准模型,利用无信息变量消除(uninformative variable elimination,UVE),连续投影算法(successive projections algorithm,SPA),竞争性自适应加权算法(competitive adaptive reweighted sampling,CARS)以及UVE-CARS、UVE-SPA等方法对SNV预处理后的光谱提取特征波长。然后,分别基于全光谱数据和所选特征变量数据,建立线性偏最小二乘回归(PLSR)和非线性BP神经网络模型。结果表明:UVE-CARS算法可以有效地减少提取变量个数(共提取26个,仅占全光谱范围的3.2%),PLSR和BP模型的预测集R2分别为0.974 6和0.978 4,RMSE分别为0.286 3%和0.250 3%。非线性BP模型预测结果整体优于线性PLSR模型,在BP模型中,UVE-CARS-BP预测精度最高,预测集的R2和RMSE的值分别为0.978 4, 0.250 3%。综上,基于高光谱成像技术建立的SNV-UVE-CARS-BP模型,可以实现金银花贮藏过程中CGA含量变化的快速无损预测。     

Piezo-actuated zona-drilling improves the fertilisation of OPS vitrified mouse oocytes

The present study was designed to investigate fertilisation of open pulled straw (OPS) vitrified mouse oocytes drilled with piezo-micromanipulation method and their subsequent in vitro and in vivo developmental capacity. Ovulated mouse oocytes were vitrified using the OPS method. After warming, the zona pellucida of a group of vitrified-warmed oocytes was drilled by piezo-micromanipulation. Groups of (a) vitrified, (b) vitrified/drilled and (c) fresh control oocytes were fertilised in vitro. The fertilisation rate of vitrified-warmed oocytes was significantly lower than that of fresh oocytes (45.0 +/- 12.6% vs. 85.2 +/- 6.8%, P < 0.05), and was significantly improved by zona-drilling (85.4 +/- 7.3%). However, blastocyst formation rates of the vitrified and vitrified/drilled groups were significantly lower than those of the fresh controls (65.7 +/- 7.0% and 66.4 +/- 2.5% vs. 86.6 +/- 4.3%, respectively, P < 0.05). The cell number of blastocysts from the vitrified/drilled or the vitrified group was not different from that of the controls. Embryo transfer resulted in pregnancy in all three groups, but the rate of development to term was lower in the vitrified/drilled or vitrified groups than in the controls (16.6 +/- 0.7% or 36.0 +/- 2.4% vs. 51.3 +/- 2.9%, respectively). Our results demonstrated that zona-drilling with piezo-micromanipulation could improve fertilisation in OPS vitrified mouse oocytes but did not increase the overall number of vitrified oocytes developing to term.     

旅游活动对泰山景区土壤质量的影响

随着旅游活动在全球范围内的迅速发展,其对自然环境的影响也成为旅游环境研究的热点。国外关于旅游对土壤性质影响的研究始于20世纪60年代,研究内容主要涉及到践踏、露营等不同类型与不同强度旅游干扰对土壤理化性质的影响等[1]。     

PLANT DENSITY,IRRIGATION AND NITROGEN MANAGEMENT: THREE MAJOR PRACTICES IN CLOSING YIELD GAPS FOR AGRICULTURAL SUSTAINABILITY IN NORTH-WEST CHINA

• A relative yield of 70% was obtained under both border and drip irrigation.• Drip irrigation saved water and lowered yield variability compared to border irrigation.• Drip irrigation led to accumulation of soil nitrogen and phosphorus in the root zone.• Relative yield may increase 8% to 10% by optimizing field management.• Plant density, irrigation and nitrogen are major factors closing yield gap in NW China.Agriculture faces the dual challenges of food security and environmental sustainability. Here, we investigate current maize production at the field scale, analyze the yield gaps and impacting factors, and recommend measures for sustainably closing yield gaps. An experiment was conducted on a 3.9-ha maize seed production field in arid north-western China, managed with border and drip irrigation, respectively, in 2015 and 2016. The relative yield reached 70% in both years. However, drip irrigation saved 227 mm irrigation water during a drier growing season compared with traditional border irrigation, accounting for 44% of the maize evapotranspiration (ET). Yield variability under drip irrigation was 12.1%, lower than the 18.8% under border irrigation. Boundary line analysis indicates that a relative yield increase of 8% to 10% might be obtained by optimizing the yield-limiting factors. Plant density and soil available water content and available nitrogen were the three major factors involved. In conclusion, closing yield gaps with agricultural sustainability may be realized by optimizing agronomic, irrigation and fertilizer management, using water-saving irrigation methods and using site-specific management.     

不同光照条件对兴安杜鹃和迎红杜鹃光合生理的影响

通过对全光照、半光照和遮荫处理的兴安杜鹃和迎红杜鹃进行光合生理指标研究。结果表明:光照条件对兴安杜鹃和迎红杜鹃的光合作用影响显著,而对呼吸作用影响不显著,光合作用和呼吸作用对光环境变化的反映是独立的;在光照处理中半光条件下兴安杜鹃和迎红杜鹃生长状态最好;在全光照条件下迎红杜鹃的光合速率、蒸腾速率和呼吸速率都高于兴安杜鹃;在半光条件下迎红杜鹃气孔导度和胞间CO2体积分数高于全光照和遮荫处理;兴安杜鹃和迎红杜鹃在栽培应用上注意光照条件,采取乔灌混栽效果更佳。     

发展草地生态畜牧业促进石漠化治理初探——以贵州安顺市为例

根据喀斯特石漠化研究成果,喀斯特山区石漠化形成的主要原因是人为不合理干扰活动和喀斯特山区特有的脆弱生态环境所致。发展草地生态畜牧业是石漠化治理的有效措施之一,并提出了现有条件下发展草地生态畜牧业治理石漠化的几种模式。     

Root morphological traits of winter wheat under contrasting environments

Roots strongly influence the growth and yield of field crops. We characterized root morphological traits of 10 winter wheat varieties in order to determine the extent they were influenced by the environments and impacted grain yield under two irrigation regimes at Bushland (a cooler, drier site with clay loam soil) and Uvalde (a warmer, wetter site with clay soil) in Texas, USA, from 2015 to 2017. Major root traits, including root diameter, specific root length (SRL), root surface area (SSA), tissue mass density (TMD), root length density (RLD), and root weight density, were measured and related to one another and to grain yield. RLD of wheat decreased but SRL and SSA increased with soil depth. Irrigation was second to environment in affecting root traits. Compared with Uvalde, the environment of Bushland promoted deeper root growth, higher TMD, but reduced SRL and SSA. Water deficit inhibited RLD and root: shoot ratio at Bushland, but moderately promoted them at Uvalde. Both SRL and RLD were positively associated with grain yield, with the former relation stronger under drought. The dichotomy of “conservative” versus “acquisitive” root strategy partially explained the variations of root traits of winter wheat in contrasting environments.     

国外替代农业的产生与现状分析

本文综合论述了国外替代农业产生的背景、思想和理论基础,几种主要形式和技术措施、发展现状,国外其评价及发展趋势。通过对常规农业和替代农业的分析、对比,探索了未来农业发展的道路。