CRU数据集在黑龙江省ET_0计算中的应用

针对我国参考作物蒸发蒸腾量(ET0)计算中存在的气象数据不易获取、现有作物需水量数据空间分辨率较低等问题,以黑龙江省为例,基于10 min分辨率的CRU CL 2.0数据集,采用FAO Penman-Monteith公式建立了适于计算区域ET0的栅格模型,并应用黑龙江省14个气象站的实测气象数据对该模型计算成果进行了验证。结果表明:采用CRU CL 2.0数据计算区域ET0是可行的,其计算结果与应用实测气象数据计算所得的ET0符合较好,不仅可以细化我国ET0和作物需水量研究成果,也为气象资料缺乏情况下的ET0计算供了一种新的计算模式。

1901～2013年GPCC和CRU降水资料在中国大陆的适用性评估

利用1901~2013年中国大陆地区的气象台站实测降水资料,对东英吉利(East Anglia)大学气候研究中心(Climatic Research Unit,CRU)和全球降水气候中心(Global Precipitation Climatology Centre,GPCC)的降水资料分别从季节、年际和年代际尺度上进行了评估。结果表明:1961~2013年CRU与GPCC降水资料均能较准确地描述中国大陆地区的降水特征,且在东部较西部地区、夏季较冬季与站点实测降水情况更为一致。将中国大陆划分为不同区域并在其季节、年际和年代际时间尺度上通过比较降水偏差绝对值的百分比、均方根误差和相关系数等统计量后发现:CRU在青藏高原和其它较大的山脉附近与站点实测降水的差别较大,且年均降水趋势在西北一带的阿尔金山脉、黄土高原、东南地区和长江下游地区,比实测降水的年均趋势小、甚至出现趋势相反的情况。此外,CRU降水的年代际变化趋势也偏小。而GPCC数据不论是降水量还是降水趋势都更接近实际情况。在1901~1961年,通过与65个长期气象观测站点的降水时间序列比较发现,CRU在110°E以西地区与站点观测的降水资料间的差别较大,而GPCC与站点观测资料的吻合较好。最后,利用1961~2013年两套降水资料和站点实测资料分别计算了标准化降水指数(SPI),简单分析了中国大陆地区的干旱变化,发现GPCC对旱涝的时空变化特征的描述比CRU更接近站点实际观测;并且CRU也没有反映出1997年夏季中国地区出现的严重干旱情况,而GPCC较为准确地反映出了这一干旱事件特征。因此,本文的研究结果认为,就中国大陆地区长时期降水资料而言,GPCC的适用性优于CRU。

L-甲硫氨酸和L-半胱氨酸混合液对抗二氯喹啉酸孔雀稗生长、生理和乙烯信号途径相关基因表达的影响

除草剂二氯喹啉酸长期使用已导致部分稗草出现高水平抗药性,氨基酸在植物代谢中发挥着重要作用。本研究以抗二氯喹啉酸的孔雀稗Echinochloa crus-pavonis为试材,研究了在500μmol/L二氯喹啉酸胁迫下,外源添加200、400、600和800μmol/L系列浓度的L-甲硫氨酸和L-半胱氨酸的等摩尔浓度混合液处理,对抗性型孔雀稗生长、抗氧化酶和解毒酶活性以及乙烯生物合成及氰化物解毒相关基因表达的影响。结果表明:在没有除草剂胁迫时,上述氨基酸混合液处理对抗性孔雀稗生长无显著影响,对其超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性也没有影响,仅600和800μmol/L氨基酸混合液处理可显著抑制多酚氧化酶(PPO)活性;而在500μmol/L的二氯喹啉酸胁迫下,氨基酸混合液预处理对抗性稗草的生长存在低浓度促进高浓度抑制现象,同时,随着氨基酸混合液浓度升高,稗草抗氧化酶(SOD、CAT、PPO)及解毒酶谷胱甘肽S-转移酶(GSTs)活性整体表现为逐渐降低趋势,而过氧化物酶(POD)活性则逐渐升高。此外,外源添加L-甲硫氨酸和L-半胱氨酸混合液处理显著激活了乙烯信号途径,乙烯信号途径1-氨基环丙烷基-1-羧酸(ACC)合成酶基因、ACC氧化酶基因以及与氰化物解毒相关的β-氰丙氨酸合成酶基因EC_CAS均随着氨基酸混合液浓度的升高而上调表达,其中600和800μmol/L混合液预处理强烈诱导了所有5个测试基因的表达水平。本研究发现,外源施加L-甲硫氨酸和L-半胱氨酸混合液可通过影响植物乙烯信号途径而调控稗草对除草剂二氯喹啉酸的抗性,对降低稻田中除草剂的施用量以及减缓稗草对二氯喹啉酸抗性的产生和发展均有重要意义。

Influence of vapor pressure deficit on vegetation growth in China

Vapor pressure deficit(VPD)plays a crucial role in determining plant physiological functions and exerts a substantial influence on vegetation,second only to carbon dioxide(CO_(2)).As a robust indicator of atmospheric water demand,VPD has implications for global water resources,and its significance extends to the structure and functioning of ecosystems.However,the influence of VPD on vegetation growth under climate change remains unclear in China.This study employed empirical equations to estimate the VPD in China from 2000 to 2020 based on meteorological reanalysis data of the Climatic Research Unit(CRU)Time-Series version 4.06(TS4.06)and European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA-5).Vegetation growth status was characterized using three vegetation indices,namely gross primary productivity(GPP),leaf area index(LAI),and near-infrared reflectance of vegetation(NIRv).The spatiotemporal dynamics of VPD and vegetation indices were analyzed using the Theil-Sen median trend analysis and Mann-Kendall test.Furthermore,the influence of VPD on vegetation growth and its relative contribution were assessed using a multiple linear regression model.The results indicated an overall negative correlation between VPD and vegetation indices.Three VPD intervals for the correlations between VPD and vegetation indices were identified:a significant positive correlation at VPD below 4.820 hPa,a significant negative correlation at VPD within 4.820–9.000 hPa,and a notable weakening of negative correlation at VPD above 9.000 hPa.VPD exhibited a pronounced negative impact on vegetation growth,surpassing those of temperature,precipitation,and solar radiation in absolute magnitude.CO_(2) contributed most positively to vegetation growth,with VPD offsetting approximately 30.00%of the positive effect of CO_(2).As the rise of VPD decelerated,its relative contribution to vegetation growth diminished.Additionally,the intensification of spatial variations in temperature and precipitation accentuated the spatial heterogeneity in the impact of VPD on vegetation growth in China.This research provides a theoretical foundation for addressing climate change in China,especially regarding the challenges posed by increasing VPD.

Spatiotemporal pattern of climate change in the China-Myanmar Economic Corridor from 1901 to 2018

The China-Myanmar Economic Corridor(CMEC) is an important part of China's Belt and Road Initiative and an important area for global ecology and biodiversity. In this study, the annual and seasonal spatiotemporal patterns of temperature and precipitation in the CMEC over the past century were investigated using linear tendency estimation, the Mann-Kendall mutation test, the T-test, and wavelet analysis based on the monthly mean climatic data from 1901 to 2018 released by the Climatic Research Unit(CRU) of the University of East Anglia, UK. The results show that the CMEC demonstrated a trend of warming and drying over the past 100 years, and the rate of change in Myanmar was stronger than that in Yunnan Province of China. The warming rate was 0.039 ℃/10a. Precipitation decreased at a rate of -6.1 mm/10a. From the perspective of spatial distribution, temperature was high in the central and southern, low in the north of the CMEC, and the high-temperature centers were mainly distributed in the southern plain and river valley. Precipitation decreased from west to east and from south to north of the CMEC. From the perspective of the rate of change, warming was stronger in central and northern CMEC than in southern and northeastern CMEC. The rate of precipitation decline was stronger in the central and western regions than in the eastern region. This study provides a scientific reference for the CMEC to address climate change and ensure sustainable social and economic development and ecological security.

稻田稗草种群对氰氟草酯的抗性水平和抗性机理初探

为明确来自湖南和江西省稻田稗草种群对氰氟草酯的抗性水平和抗性机理,采用整株生物测定法、基因测序、代谢酶抑制剂联用试验进行了研究。结果显示:R1、R2、R3种群对氰氟草酯的抗性指数分别为3.08、2.19、3.83,均为中抗水平;R4种群抗性指数为1.45,为低抗水平。与敏感种群相比,R1种群存在Ile-2041-Val突变,R2种群中存在Ile-2041-Val、Asp-2078-Gly突变,且细胞色素P450酶抑制剂马拉硫磷和谷胱甘肽硫转移酶抑制剂NBD-Cl均能提高R1和R2种群对氰氟草酯的敏感性;R3种群中存在Trp-2027-Arg突变,且NBD-Cl可以提高其对氰氟草酯的敏感性;R4种群中存在Cys-2088-Tyr突变,马拉硫磷和NBD-Cl不能逆转其对氰氟草酯的抗性。研究表明,稗草种群R1、R2、R3对氰氟草酯的中等水平抗性是由靶标抗性和非靶标抗性共同介导,种群R4对氰氟草酯的低水平抗性主要是由靶标抗性介导。

Comprehensive applicability evaluation of four precipitation products at multiple spatiotemporal scales in Northwest China

Precipitation plays a crucial role in the water cycle of Northwest China.Obtaining accurate precipitation data is crucial for regional water resource management,hydrological forecasting,flood control and drought relief.Currently,the applicability of multi-source precipitation products for long time series in Northwest China has not been thoroughly evaluated.In this study,precipitation data from 183 meteorological stations in Northwest China from 1979 to 2020 were selected to assess the regional applicability of four precipitation products(the fifth generation of European Centre for Medium-Range Weather Forecasts(ECMWF)atmospheric reanalysis of the global climate(ERA5),Global Precipitation Climatology Centre(GPCC),Climatic Research Unit gridded Time Series Version 4.07(CRU TS v4.07,hereafter CRU),and Tropical Rainfall Measuring Mission(TRMM))based on the following statistical indicators:correlation coefficient,root mean square error(RMSE),relative bias(RB),mean absolute error(MAE),probability of detection(POD),false alarm ratio(FAR),and equitable threat score(ETS).The results showed that precipitation in Northwest China was generally high in the east and low in the west,and exhibited an increasing trend from 1979 to 2020.Compared with the station observations,ERA5 showed a larger spatial distribution difference than the other products.The overall overestimation of multi-year average precipitation was approximately 200.00 mm and the degree of overestimation increased with increasing precipitation intensity.The multi-year average precipitation of GPCC and CRU was relatively close to that of station observations.The trend of annual precipitation of TRMM was overestimated in high-altitude regions and the eastern part of Lanzhou with more precipitation.At the monthly scale,GPCC performed well but underestimated precipitation in the Tarim Basin(RB=-4.11%),while ERA5 and TRMM exhibited poor accuracy in high-altitude regions.ERA5 had a large bias(RB≥120.00%)in winter months and a strong dispersion(RMSE≥35.00 mm)in summer months.TRMM showed a relatively low correlation with station observations in winter months(correlation coefficients≤0.70).The capture performance analysis showed that ERA5,GPCC,and TRMM had lower POD and ETS values and higher FAR values in Northwest China as the precipitation intensity increased.ERA5 showed a high capture performance for small precipitation events and a slower decreasing trend of POD as the precipitation intensity increased.GPCC had the lowest FAR values.TRMM was statistically ineffective for predicting the occurrence of daily precipitation events.The findings provide a reference for data users to select appropriate datasets in Northwest China and for data developers to develop new precipitation products in the future.

CRU产品在中国大陆的干旱事件时间性效用评估

基于1980—2016年CGDPA(China gauge-based precipitation daily analysis dataset)和PM-Ep(potential evapotranspiration calculated by Penman-Monteith)资料,以标准化降水蒸散指数(SPEI)为干旱指标,采用6种评估指标综合评价CRU降水(CRU-P)和潜在蒸散发(CRU-Ep)产品在中国大陆对干旱事件时间性的监测效用。结果表明:CRU-P与CGDPA在中国大陆空间分布特征具有较好的相似性,而CRU-Ep与PM-Ep有明显差异,但它们在大部分地区的精度较高;SPEIc(基于CRU-P和CRU-Ep计算的SPEI)在中国东部和西部部分地区的性能较好,其与SPEIm(基于CGDPA和PM-Ep计算的SPEI)的相关系数在中国东部、西北、西南地区均大于0.7,均方根误差小于0.8,命中率大于0.6;利用文中提出的干旱率、平均开始时间误差、平均结束时间误差评价得出不同时间尺度的SPEIc在中国大陆大部分地区监测干旱事件时间性的精度较高,且在中国东部地区优于西部地区;基于长序列CRU产品驱动的SPEI可适用于中国东部、西北、西南地区的干旱监测。

CRU高分辨率格点降水资料在海河流域的适用性

利用海河流域及其子流域漳河流域的实测站点资料,采用皮尔逊相关系数、均方根误差、平均绝对误差以及相对偏差作为评价指标,对CRU(climate research unit)数据降水产品的月尺度降水数据在海河与漳河流域的适用性进行评估分析,结果表明:CRU数据在海河子流域漳河流域的适用性好于整个海河流域,各项评价结果均达到预期期望;突变性与周期性规律检验结果与以往基于实测数据分析结果相符;从相关系数角度来看,应用于2个流域的CRU数据在1990年之前整体表现良好,但在1990年后海河流域的相关系数显著下降。综上CRU数据可应用于海河流域与漳河流域的气候变化背景下水文过程模拟与分析,但应用于海河流域实测站点数据的还原时,应充分考虑其年际表现不一的问题。

基于2CRU/2PRRR并联式灌装机构的设计与工作空间分析

目的 针对目前流水线上的灌装机构,对含有不同倾角瓶子的通用性不强等问题,提出一种新型2CRU/2PRRR并联机构来解决这一问题。方法 首先用SolidWorks软件创建2CRU/2PRRR并联机构的立体模型。利用螺旋理论分析得出该机构的自由度,并用修正的Kutzbach-Grübler公式对分析得出的自由度进行验证。然后利用运动学模型和D-H法分析求解机构动平台的位置反解。最后应用Matlab软件编写相应的极限边界搜索程序,运算求解出工作空间,并给出该灌装机构在流水线的应用实例。结果2CRU/2PRRR并联机构拥有1个转动自由度,3个方向的移动自由度。工作空间为规则立方体,内部连续无空洞且无奇异位型。结论 2CRU/2PRRR并联式灌装机构结构简单、运行稳定、性能良好,完全可以满足流水线上对含有倾角的瓶子进行灌装时的运动和工作范围需求,提高了灌装机构的通用性。

中国境内稗(Echinochloa crus-galli)形态变异及其遗传和地理背景分析

采集了浙江、福建、江苏、湖南、湖北、四川、重庆、黑龙江、河南9个省的稗(Echinochloa crus-galli(L.)P.Beauv.)及其变种的33份种子,分别播种在相同的环境下,获得33个种群,测定了种群的16个形态性状,筛选出重复性好的9条ISSR引物,从33个种群中扩增出了109个位点。基于这些形态性状和ISSR位点信息,对33个种群先进行主成分分析,在此基础上再进行模糊均值聚类分析,探讨了它们的形态和遗传变化特点,及其与形态—遗传—地理背景三者之间的关系。主要结论如下:(1)33个种群可以鉴别出形态性状相对一致的4组,能够识别出西来稗(E.crus-galli var.zelayensis(Kunth)Farw.)、无芒稗(E.crus-galli var.mitis(Pursh)Peterm.)、细叶旱稗(E.crus-galli var.praticola Ohwi);(2)基于109个位点信息对33个种群进行聚类分析得到了6组,部分组与形态聚类分组有一定的对应性;(3)33个稗草种群的遗传分化受地理背景因素的影响(r=0.684,n=33,P<0.001);形态变异也有较明显的遗传背景因素(r=0.425,n=33,P<0.02)。在相对一致的稻田生境中,可能存在着形态上的趋同适应,使遗传上分化的组间在形态上又往往有交叉过渡,致使稗原变种(E.crus-galli var.crus-galli)、西来稗、无芒稗、短芒稗(E.crus-galli var.breviseta(D9ll)Podp.)在形态上难以区别;(4)基于遗传和形态数据分析,发现细叶旱稗无论在形态上,还是遗传上,均形成了明显的一组,推测与该种长期适应于干旱生境有关,建议将细叶旱稗提升为种的水平,并将其命名为Echinochloa praticola(Ohwi)Guo S L,Lu Y L,Yin L P&Zou M Y。

从对苯二甲酸生产系统的水平衡分析CRU流程简化的可行性

通过对对苯二甲酸（ＴＡ）生产过程中水含量的平衡计算与分析，并根据有关试验结果，从工艺上、经济上以及各项消耗方面，对催化剂回收单元（ＣＲＵ）流程简化（即取消浓缩、闪蒸部分）的可行性和必要性进行了探讨，并指出了存在的问题。

基于CRU数据的1901—2018年全球陆表气温时空变化特征分析

基于英国东英格利亚大学气候研究所单位时间序列网格数据集,1901—2018年的陆表平均气温、最高气温和最低气温数据(0.5°×0.5°,月值数据),采用时间序列趋势分析、趋势显著性检验、空间相关性分析等方法对气温进行年内变化、年际变化和空间分布分析.结果表明:(1)1901—2018年平均、最高、最低气温的气候倾向率(曼-肯德尔检验结果)分别为0.11℃/10 a(1.739),0.09℃/10 a(1.640)和0.12℃/10 a(1.807),表明全球具有较明显的升温趋势;(2)在步长为6 a,显著水平α=0.01的情况下,滑动t检验结果显示平均温和最高温的突变点为2个,最低温的突变点为3个,1964年的突变较明显;(3)北纬45°以北地区的最低温升温所涉及的范围比平均、最高温更大;(4)相比于最低气温,平均气温和最高气温的空间差异性变化较小,1980年以来最低气温的空间异质性呈现减小趋势.

基于CRU资料的山西百年气温时空演变特征

全球变暖的背景下,百年尺度上的区域气温变化规律,近年来已成为气候变化研究的热点。本文基于1901-2016年英国东英吉利(East Anglia)大学气候研究中心(Climatic Research Unit,CRU)提供的高分辨率、逐月气温数据集,采用一元线性回归法、滑动平均法和Mann-Kendall突变检验法分析了116年来山西气温的时空分布特征。结果表明:百年来山西年平均气温和各季节气温均呈波动上升趋势,年均和各季节气温倾向率分别为0.13℃·(10a)-1(年平均)、0.16℃·(10a)-1(春季)、0.05℃·(10a)-1(夏季)、0.09℃·(10a)-1(秋季)、0.22℃·(10a)-1(冬季),其中冬季气温增幅最大,对年均温增长的贡献最大,贡献率为42.31%,夏季气温增幅最小,贡献率也最小(9.62%)。研究时段内,山西各季节气温均发生突变,春季季均温突变开始于1993年,夏季在1917年和1996年都发生了气温突变,秋季、冬季出现突变的年份分别为2001年、1984年。空间上,山西多年平均气温和季均温均以南高北低的纬度变化规律为主,同时受到地形的影响,分别形成不同气温中心,其中冬季受地形影响最小,尤其是最冷月。

Dormancy release and germination of Echinochloa crus-galli grains in relation to galactomannan-hydrolysing enzyme activity

Echinochloa crus-galli, one of the world＇s most serious weeds, influences seriously the yield and quality of cereal crop plant.It is well known that E.crus-galli grain is dormant, but its dormant type, as well as its dormancy release and germination in relation to galactomannan-hydrolysing enzyme activity were poorly understood.The cooperation of endo-β-mannanase（EC 3.2.1.78）, β-mannosidase（EC 3.2.1.25） and α-galactosidase（EC 3.2.1.22） can hydrolyze the cell walls rich in mannan-based polymers.In the present paper, the mature grains are used as experimental materials, we investigated the water uptake of grains, the effect of removing partial endosperm, after-ripening, stratification and phytohormone on grain germination, and the change in endo-β-mannanase, β-mannosidase and α-galactosidase activities of grains during after-ripening and germination.The results showed that the freshly-collected grains were water-permeable and had only phase I and II of water uptake, while the grains after-ripened for 150 d had an obvious phase III of water uptake.In alternating photoperiod, the germination of grains freshly-collected was zero at 10–35°C, and that of half grains was 11% at 20°C only.The grain germination was notably promoted by after-ripening and stratification, but not by gibberellic acid and 6-benzyladenine at 0.0001–1 mmol L–1.β-Mannosidase activity increased during 0 to 300 d of after-ripening and then decreased.The activity of endo-β-mannanase and α-galactosidase of grains decreased with after-ripening.During grain germination, endo-β-mannanase and β-mannosidase activities obviously increased, while α-galactosidase activity decreased.Our data showed that E.crus-galli grain was a deep physiological dormant, the dormancy release by after-ripening was related to an increasing β-mannosidase activity, and its germination was closely associated with an increasing endo-β-mannanase and β-mannosidase activity; which have provided new knowledge to decrease the harm of E.crus-galli on production of cereal crop plant.

Quinclorac Resistance in Echinochloa crus-galli from China

Echinochloa crus-galli is a major weed in rice fields in China,and quinclorac has been long used for its control.Over-reliance of quinclorac has resulted in quinclorac resistance in E.crus-galli.Two resistant(R)E.crus-galli populations from Hunan,China were confirmed to be at least 78-fold more resistant to quinclorac than the susceptible(S)population.No difference in foliar uptake of 14C-labelled quinclorac was detected between the R and S plants.However,a higher level of 14C translocation and a lower level of quinclorac metabolism were found in the R plants.Basal and induced expression levels ofβ-cyanoalanine synthase(β-CAS)gene andβ-CAS activity were not significantly different between the R and S plants.However,the induction expression of 1-aminocyclopropane-1-carboxylic acid oxidase(ACO1)gene by quinclorac treatment was evident in the S plants but not in the R plants.Quinclorac resistance in the two resistant E.crus-galli populations was not likely to be related to foliar uptake,translocation or metabolism of quinclorac,nor to cyanide detoxification viaβ-CAS.Thus,target-site based quinclorac signal reception and transduction and regulation of the ethylene synthesis pathway should be the focus for further research.

Spatiotemporal variations of evapotranspiration and reference crop water requirement over 1957-2016 in Iran based on CRU TS gridded dataset

Agriculture needs to produce more food to feed the growing population in the 21st century.It makes the reference crop water requirement(WREQ)a major challenge especially in regions with limited water and high water demand.Iran,with large climatic variability,is experiencing a serious water crisis due to limited water resources and inefficient agriculture.In order to overcome the issue of uneven distribution of weather stations,gridded Climatic Research Unit(CRU)data was applied to analyze the changes in potential evapotranspiration(PET),effective precipitation(EFFPRE)and WREQ.Validation of data using in situ observation showed an acceptable performance of CRU in Iran.Changes in PET,EFFPRE and WREQ were analyzed in two 30-a periods 1957-1986 and 1987-2016.Comparing two periods showed an increase in PET and WREQ in regions extended from the southwest to northeast and a decrease in the southeast,more significant in summer and spring.However,EFFPRE decreased in the southeast,northeast,and northwest,especially in winter and spring.Analysis of annual trends revealed an upward trend in PET(14.32 mm/decade)and WREQ(25.50 mm/decade),but a downward trend in EFFPRE(-11.8 mm/decade)over the second period.Changes in PET,EFFPRE and WREQ in winter have the impact on the annual trend.Among climate variables,WREQ showed a significant correlation(r=0.59)with minimum temperature.The increase in WREQ and decrease in EFFPRE would exacerbate the agricultural water crisis in Iran.With all changes in PET and WREQ,immediate actions are needed to address the challenges in agriculture and adapt to the changing climate.

Variability and Long-Term Trend of Total Cloud Cover in China Derived from ISCCP, ERA-40, CRU3, and Ground Station Datasets

Total Cloud Cover （TCC） over China deter- mined from four climate datasets including the Interna- tional Satellite Cloud Climatology Project （ISCCP）, the 40-year Re-Analysis Project of the European Centre for Medium-Range Weather Forecasts （ERA-40）, Climate Research Unit Time Series 3.0 （CRU3）, and ground sta- tion datasets are used to show spatial and temporal varia- tion of TCC and their differences. It is demonstrated that the four datasets show similar spatial pattern and seasonal variation. The maximum value is derived from ISCCE TCC value in North China derived from ERA-40 is 50% larger than that from the station dataset; however, the value is 50% less than that in South China. The annual TCC of ISCCP, ERA-40, and ground station datasets shows a decreasing trend during 1984-2002; however, an increasing trend is derived from CRU3. The results of this study imply remarkable differences of TCC derived from surface and satellite observations as well as model simu- lations. The potential effects of these differences on cloud climatology and associated climatic issues should be carefully considered.

Effect of Toxins Isolated from Exserohilum monoceras (Drechsler) Leonard and Suggs on Echinochloa crus-galli (L.) Beauv.

Exserohilum monoceras （Drechsler） Leonard and Suggs is a potential biocontrol agent for the control of Echinochloa species. This fungus causes leaf blight in Echinochloa species, but does not damage rice. Phytotoxicity of the fungal fermented broth was evaluated through the bioassay and the active ingredients were preliminarily isolated by using silica gel column chromatography （CC） in this study. The most active fraction 5-Ⅲ was obtained and analyzed by gas chromatography-mass spectrometry （GC-MS）. The results show that 5-Ⅲ consisted of many compounds, in which 36 compounds accounted for 94.24% of total peak area. Di-n-butyl phthalate （DBP） displayed the highest activity accounted for 9.24% of the total peak area, suggesting that DBP may be one of the main active compounds produced by E. monoceras.

玉米田除草剂苯唑氟草酮的作用特性

为明确玉米田除草剂苯唑氟草酮(fenpyrazone)的最佳施药条件,以稗Echinochloa crus-galli为测试靶标,采用整株水平测定法研究了温度、光照强度、药后降雨间隔时间和杂草叶龄对其除草活性的影响。结果显示:在气温15~35℃下,苯唑氟草酮药效随温度的升高而升高,在20~35℃范围内,苯唑氟草酮药效趋于稳定,对稗的GR_(50)值在2.8~7.6 g/hm^(2)之间;随着光照强度增强,苯唑氟草酮对稗的活性显著增加,鲜重抑制率在41.19%~90.84%之间;苯唑氟草酮具有很强的耐雨水冲刷能力,施药后降雨间隔时间达到1 h以上,其除草活性与间隔时间即无显著相关性,对稗的GR_(50)值在1.7~2.4 g/hm^(2)之间;杂草叶龄会显著影响苯唑氟草酮的活性,其中1~4叶期的稗最为敏感,该条件下的GR_(50)值小于1.0 g/hm^(2)。综合来看,为保证苯唑氟草酮发挥最大药效,建议应在稗1~4叶期,选择天气晴朗、气温高于20℃的情况下施药,如药后1 h内遇降雨天气,则需进行补喷。研究结果可为苯唑氟草酮在玉米田的进一步推广应用提供科学依据。