连作百香果对土壤理化性质和微生物特性的影响及病原真菌的分离与鉴定

为了分析连作对百香果土壤理化性质及微生物的影响,本研究以种植0(未种植)、1、2、3 a的百香果根际土壤为材料,分析连作百香果对土壤理化指标、自毒潜力、微生物数量的影响,并对连作百香果根际土壤病原真菌进行分离、鉴定.结果表明,随着种植年限的增加,百香果根际土壤pH呈显著下降趋势,土壤总氮、磷、钾含量变化较小,而有效性氮...     

中国大豆花叶病抗源和抗性鉴别寄主的鉴定与评价

收集大豆抗大豆花叶病(SMV)抗源和鉴别寄主40份,通过接种Cho和Goodman划分的抗大豆花叶病毒株系SMV G1-G7,了解这些材料对该株系的抗性反应.同时比较了其中部分材料对中国学者划分的SMV Sc1-Sc17株系的抗性反应.结果感病材料无论对SMV G1-G7株系,还是SMV Sc1-Sc17株系均表现感病;但是,齐黄1、科丰1、早18和8101等对SMV G1-G7株系均表现抗病的材料,对SMV Sc1-Sc17株系却表现出部分抗病;而另外一些材料,如:诱变30、徐豆1、文丰5、铁6915、齐黄10和Harosoy等对SMV G1-G7株系的抗性反应却与北美的鉴别寄主相同.结果表明:无论是对 SMV G1-G7株系,还是对SMV Sc1-Sc17株系,抗病材料的抗性遗传基础是相似的;中国一些大豆花叶病毒株系的致病力强于国外的株系.因此,结合国外的SMV株系鉴定系统,创建一套统一的SMV株系鉴定系统是可行的.     

中国粳稻起源的探讨

 从多学科角度探讨了中国粳稻的起源。认为我国的粳稻独立起源于偏粳的普通野生稻，籼、粳稻是平行演化的；我国粳稻量重要的起源地是在长江中下游的平原沼泽地带，其中心区域位于太湖流域。     

基于改进GM(1,N)模型的我国大豆价格影响因素分析及预测研究

大豆是我国重要的粮食作物和油料作物,其价格对于国民经济尤其是农业经济的影响意义深远。大豆价格的稳定对于我国大豆市场的健康发展有着重要的现实意义。在灰色理论的基础上,提出了一种改进GM(1,N)大豆价格预测模型,首先运用灰色关联分析法对我国大豆价格的影响因素进行分析,选择主要的影响因素;再将这些影响因素作为模型的相关因素变量,构建GM(1,N)大豆价格预测模型。采用2010-2015年的大豆数据进行实证研究,模型选取国内大豆自给量、世界大豆产量、国民消费价格指数、消费者信心指数4个变量作为相关因素变量;模型预测误差为2.10%,预测精度较高,能够较好地掌握大豆价格的变化规律,可以为大豆价格市场预测及国家宏观政策的制定提供理论指导。     

接种AMF对间作大豆生长及有机磷利用的影响

为了研究接种丛枝菌根真菌(AMF)与间作种植模式对红壤上间作大豆磷素吸收利用及生长的影响,通过三室隔网盆栽模拟试验研究了分室磷[不添加磷(P0)、有机磷(OP50)添加和根室不接种(NM)、根室接种丛枝菌根真菌Glomus mosseae(GM)]对大豆生长及磷素利用的影响。结果表明:在OP50处理下,无论何种种植模式,不接种处理下根长均显著高于接种处理,无论接种与否,单作处理下大豆根长均高于间作处理。在OP50处理下,接种GM处理地上部分生物量均明显高于不接种处理,在P0处理下地上部分生物量具有相同趋势。间作处理下,分室添加磷与不添加磷时,GM处理的植株生物量较NM处理分别提高了27.52%和48.76%。单作处理下,分室添加磷与不添加磷时,GM处理的植株生物量较NM处理分别提高了28.49%和27.65%。大豆植株根系磷含量在单作-GM-OP50组合处理下最高。在接种GM处理下,无论是否添加磷,间作大豆根系磷吸收效率均显著高于单作处理。因此,综合菌根侵染率、生物量、磷含量以及磷吸收效率等指标,接种GM和分室添加50 mg·kg-1有机磷处理能更有效地促进间作大豆的生长及磷素的吸收。     

基于荧光标记SSR的CID法快速鉴定福建茶树品种

茶树品种真实性鉴定是茶树种质资源研究的重要组成部分,是茶树品种知识产权保护的前提。在茶树基因组上按照均匀分布的原则选择45个SSR标记合成荧光标记引物,利用这些标记引物对54个福建无性系茶树品种进行PCR扩增,标记基因型分型后进一步筛选出9个SSR标记核心引物。这批核心引物的多态性信息含量(Polymorphism information content,PIC)均大于0.5,等位位点数在3~5之间,基因型数在5~10之间,属于高度多态性引物且方便进行基因型数据统计,适宜用来进行无性系茶树品种的真实性鉴定。利用其中的6个标记核心引物建立了54个福建无性系茶树品种的品种鉴别图(Cultivar identification diagram,CID),该CID能直观地提供对其中任意品种进行鉴定所需要的标记引物以及相应的标记基因型,且能够方便地进行扩容以用来对更多的无性系茶树品种进行真实性鉴定。利用该方法对无性系茶树品种进行真实性鉴定,操作方便、快速准确、稳定性高、实用性强。本实验所获得的茶树品种鉴定图(CID)对茶树品种知识产权保护,以及促进茶树品种选育工作健康可持续发展具有重要的意义。     

根表铁胶膜对镉污染土壤水稻吸镉量的影响(英文)

通过采用镉污染的土壤—河砂—营养液联合培养的方法,研究了在水稻分蘖期施铁对水稻根表铁胶膜中铁及铁胶膜吸附镉的影响。设四个亚铁(Fe~(2+))处理水平分别为:0、30、50、70mg/L,研究施铁浓度与水稻根表铁氧化物胶膜的数量和吸附镉量之间的关系。结果表明,施铁处理的铁胶膜中铁的含量比不施铁(0处理)的高,但在其他三种处理 (30、 50、70mg/L)中,随施铁浓度的升高而降低。另外,施铁浓度与铁胶膜的数量呈正相关,所以,铁胶膜吸附镉与施铁浓度呈正相关。在水稻的另外三个时期:拔节、孕穗、灌浆期,对该问题将作进一步研究。     

不同土壤水分含量对水稻水分利用特征的影响

 采用控制土壤水分含量的盆栽实验,研究了土壤水分含量对水稻水分利用特性的影响。结果表明,常规水作累积耗水量显著高于覆膜未淹水处理,但稍低于覆膜淹水处理;覆膜轻度水分胁迫或无胁迫处理不仅能够维持和提高产量,水分利用效率也有所提高。随着土壤水分含量的降低,全生育期水稻累积耗水量、各生育期耗水量及耗水强度逐渐降低,且田间持水量与全生育期累积耗水量呈极显著二次曲线相关。无水分胁迫覆膜处理下拔节孕穗期耗水量及模比系数高于其他生育期,其他处理耗水量和模比系数在乳熟期最高。随着土壤水分含量降低,抽穗开花期前各生育期水稻耗水模比系数有降低趋势,其后则有升高趋势;耗水强度下降;有效穗数和实粒数减少,产量逐渐降低,水分生产率先上升后下降。水稻产量与水分利用率具有显著二次曲线相关性。     

水稻抗褐飞虱遗传和育种研究

综述了水稻抗褐飞虱基因资源的鉴定及其分布特点、水稻抗褐飞虱主基因定位和QTL分析、水稻抗褐飞虱遗传的“基因对基因”关系以及水稻品种对褐飞虱的抗虫机制与褐飞虱对抗虫品种的适应等4个方面的研究进展，同时简述了抗褐飞虱基因的育种利用现状，并对今后抗褐飞虱遗传和育种利用研究作了展望。     

AMF接种与根系分隔对红壤上间作玉米生长及磷素吸收的影响

通过盆栽模拟试验研究比较以Glomus mosseae(GM)和Glomus etunicatum(GE)为接种剂,设置不同根系分隔方式(不分隔,隔尼龙网,隔塑料膜)对间作玉米植株生长及磷素吸收累积的影响。结果表明,两种菌根真菌GM和GE对玉米根系的侵染效果相近,GM为玉米优势丛枝菌根真菌(AMF),接种GM使玉米根长、地上部和根系生物量、地上部和根系磷含量、磷吸收量均显著提高;接种GE显著降低了玉米根冠比、株高和根系磷吸收效率。间作体系不同根系分隔方式对玉米的影响也不同,根系隔尼龙网处理显著降低了玉米根长和根系生物量,显著提高了根系的磷含量;根系隔塑料膜处理对玉米的地上部和根系磷含量、磷吸收量以及根系磷吸收效率均起显著降低作用。所有复合处理中,以GM不分隔处理组合对间作玉米的生长及磷素累积的促进作用最好。     

The effect of molecular weight and the linear velocity of drum surface on the properties of electrospun poly(ethylene terephthalate) nonwovens

In this study, we evaluated the effect of the molecular weight of the polymer on electrospun poly(ethylene terephthalate) (PET) nonwovens, and their mechanical properties as a function of the linear velocity of drum surface. Polymer solutions and electrospun PET nonwovens were characterized by means of viscometer, tensiometer, scanning electron microscope (SEM), wide angle X-ray diffraction measurement (WAXD) and universal testing machine (UTM). By keeping the uniform solution viscosity, regardless of molecular weight differences, electrospun PET nonwovens with similar average diameter could be obtained. In addition, the mechanical properties of the electrospun PET nonwovens were strongly dependent on the linear velocity of drum surface. From the results of the WAXD scan, it was found that the polymer took on a particular molecular orientation when the linear velocity of drum surface was increased. The peaks became more definite and apparent, evolving from an amorphous pattern at 0 m/min to peaks and signifying the presence of crystallinity at 45 m/min.     

Effect of water saving management practices and nitrogen fertilizer rate on crop yield and water use efficiency in a winter wheat–summer maize cropping system

Deficit irrigation (DI) is a water-saving irrigation strategy in which irrigation water is applied at amounts less than full crop-water requirements. Some researchers have suggested that greater increases in water use efficiency (WUE) could be realized if DI was used in combination with water conservation or rainwater harvesting techniques. The objective of this six-year field study was to determine the effect of DI in combination with straw mulch (SM) or plastic film-mulched ridge and straw-mulched furrows (RF) on grain yield and WUE in a winter wheat-summer maize rotation. Interactive effects between the water-saving management practices and N fertilizer rate were also investigated. Results indicated that maize yields in the RF + DI and SM + DI treatments were as much as 1.6 times those in the DI and conventional furrow irrigation (CFI) treatments. Over the six-year study, total maize yield in the RF + DI treatment was 5580 kg/ha more than in the CFI treatment and 6500 kg/ha more than in the DI treatment. Wheat yields in the RF + DI and SM + DI treatments were similar to the CFI treatment but slightly more than in the DI treatment. At harvest, there was no significant difference in water storage in the 0-200 cm soil profile among the RF + DI, SM + DI, DI, and CFI treatments. Nitrogen fertilizer application significantly increased maize and wheat yield compared to the unfertilized treatment; however, there was no further yield response when the N application rate exceeded 120 kg N/ha. In summary, these results indicated that DI in combination with SM or RF practices increased crop yield and WUE in the winter wheat-summer maize crop rotation. Compared to CFI practices, the SM + DI and RF + DI practices reduced the amount of irrigation water applied over a six-year period by about 350 mm.     

Effect of water deficits on within-plot variability in growth and grain yield of spring wheat in northwest China

For adapted cultivars under normal crop densities, biological yield is largely determined by the pool of available resources, e.g. water, nutrients and photosynthetically active radiation, while the nature and intensity of intraspecific competition plays an important role in determining the magnitude of harvest index (HI). Water deficits can drastically reduce the HI from its genetic potential to zero. This study was conducted to determine the effect of drought-weighted intraspecific competition on the HI and, consequently, the grain yield in spring wheat populations along a natural moisture gradient in northwestern China. Along the natural moisture gradient (annual mean rainfall decreased 328→204→185 mm per year, supplemented with 70 mm of irrigation), culm size inequality (as measured by the Gini coefficient of above-ground biomass per culm) always increased, and Lorenz curves were more concave. HI decreased significantly in 1999 (0.364→0.345→0.307) and 2000 (0.341→0.303→0.251). There was a significant negative correlation between the Gini coefficient and the HI of spring wheat along the moisture gradient (R²=0.92, P<0.01). These results suggested that size hierarchies in spring wheat populations are closely correlated with the water regime in the field, and that under greater drought stress there are relatively more smaller plants with lower HI (size-dependent reproductive allocation). Size inequality is an index of competitive status in plant populations under stress environments. Agriculturally, greater size inequality may result in a competitive cost for energy and photosynthetic products, in other words, growth redundancy, which is detrimental to reproductive allocation and consequently, grain yield. The results support the view that stand uniformity in field crops is an important mechanism for increasing grain yield.     

气候变化下红茴砂在中国潜在适生区的最大熵生态位模型预测

红茴砂是姜科茴香砂仁属多年生草本植物,我国仅在海南地区有自然分布,是具有很高药用价值的濒危植物。为了解红茴砂在未来气候变化下的潜在适生区及其主要环境影响因子,以期对红茴砂的保育提供科学指导,将45条红茴砂分布位点数据与20个环境因子相结合,运用最大熵生态位模型MaxEnt和ArcGIS软件模拟了当前气候和未来2050年RCP2.6和RCP8.5两种不同气候条件下红茴砂在中国的潜在分布区,并分析影响红茴砂分布的主导环境因子。结果表明：当前气候条件下,红茴砂适生区总范围在18°~32° N、27°~122° E,面积约为1.24×10⁶ km²,主要集中分布在海南、贵州、福建、广东、广西、云南等地;影响红茴砂地理分布的主导环境因子为最湿月降水量、最暖季度降水量、年均温度变化范围、最冷月份最低温、海拔和最热季度均温,累计贡献率达87%;在未来2050年RCP2.6和RCP8.5两种不同气候情景下,红茴砂适生区域丧失面积均达到95%以上,潜在分布区缩小到云南、四川、西藏、贵州和台湾这5个省区,新增区域主要在西藏东南部和四川中南部,同时潜在总适生区和高适生区的质心有向西北方迁移的趋势。     

盐胁迫下亚精胺浸种对水稻种子萌发的影响

采用四个处理:A为清水对照,B为200 mmol/L NaCl,C为200 mmol/LNaCl+1.0 mmol/L Spd,D为1.0mmol/L Spd。对水稻种子进行处理,研究盐胁迫下亚精胺浸种对水稻种子萌发的影响。结果显示:用200 mmol/L NaCl溶液浸种时,种子萌发率明显降低,用1 mmol/L Spd溶液处理过的水稻种子,其发芽势、发芽指数、活力指数明显增加,并且胚芽的伸长长度增加。而用200 mmol/L NaCl溶液和1.0 mmol/L Spd溶液共同处理过的水稻种子,其发芽势、发芽指数、活力指数与对照无明显差别,说明亚精胺浸种不仅可以促进水稻种子的萌发,还可以缓解盐胁迫对水稻种子的毒害作用。     

Use of field-integrated information in GIS-based maps to evaluate Moko disease (Ralstonia solanacearum) in banana growing farms in Colombia

Ralstonia solanacearum (formerly Pseudomonas solanacearum) causes large losses in more than 200 different cultivated plant species. Banana and plantain “Moko” disease is caused by R. solanacearum race 2. Moko disease may cause 100% loss if prompt control measures are not applied. Although a number of investigations have been carried out, many ecological and epidemiological aspects of R. solanacearum race 2 are still unknown, particularly in the tropics. Bacteria dispersion occurs by infested tools, soil, water, insects, domestic animals and agricultural labourers. Alternative hosts have been described which may contribute to inoculum availability in crop fields. In banana crops, cable-ways are routinely used to transport fruit and materials inside plantations. In most humid tropical areas, drainage channels are made to evacuate excess soil water. It is thought that agricultural activities associated with drainage channels and cable-ways may play a role in bacteria dispersion but individual contributions have not yet been quantified. In this work we have used field-integrated information in geographical information systems (GIS)-based maps to evaluate Moko presence in the Urabá region of Colombia, during three different time periods. A previously described risk index (RI) and losses throughout the three periods were quantified. A regression model was developed to quantify the relationship between infested area and distance from every Moko focus to the nearest cable-way and drainage channels. Farms were grouped into four different profiles according to the RI. Parameters calculated using the regression model showed that 76% of Moko foci detected during the three time periods were associated with cable-ways used for transport of fruit and consumables. This finding has important implications for disease management since bacteria spread in these ways may be prevented by simple measures taken inside plantations.     

Impacts of transgenic Bt cotton on a non-target pest, Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae), in northern China

Transgenic Bt (Bacillus thuringiensis) cotton has been effectively used to control the cotton bollworm, Helicoverpa armigera (Hübner) in China. However, in recent years, following the wide commercialization of Bt cotton in northern China there have been frequent outbreaks of the non-target pest Apolygus lucorum (Meyer-Dür). To clarify how transgenic cotton contributes to these outbreaks, a four-year field investigation of population dynamics and laboratory life table studies were carried out from 2007 to 2010 to evaluate the impact of two transgenic cotton cultivars (SGK321 expressing Cry1Ac + CpTI and GK12 expressing Cry1Ac) and their corresponding parental non-transgenic lines (Shiyuan321 and Simian3) on A. lucorum. There were no significant differences in the population densities of A. lucorum found in Bt cotton and non-Bt cotton plots, whether one compared those that had received insecticide treatments or those that had not. However, population densities of A. lucorum were significantly lower in pesticide treated plots than in controls. Furthermore, there were no significant differences in the net reproductive rates, generation times or intrinsic rates of increase of A. lucorum when reared on either Bt or non-Bt cotton cultivars. These results suggest that Bt cotton has no direct positive or negative effects on the biology of A. lucorum, so the most logical explanation for the observed outbreaks is the decrease in pesticide applications following the commercial release of Bt cotton.     

硼对大豆愈伤组织的细胞结构及形态的影响

硼是植物生长发育必需的微量元素之一,对维持植物细胞壁与细胞膜的结构和功能发挥起着重要的作用.在对大豆愈伤组织诱导培养技术成熟的基础上,研究高浓度的硼对大豆愈伤组织的细胞结构和细胞形态的影响,探讨组织培养中硼对愈伤组织诱导与再生的调节作用采用植物组织培养的方法,在硼酸含馈不同的培养基上诱导大豆下胚轴产生愈伤组织,并进行继代培养试验结果表明:下胚轴在硼酸浓度大于70 mg·L-1的培养基上诱导20 d后.一些新生的愈伤组织结构疏松,细胞分散,细胞间的正常连接无法形成.把这些结构疏松的愈伤组织在正常的培养基MS+2,4-D0.4 mg·I-1上进行继代试验,发现细胞仍具有分裂能力,新生的愈伤组织细胞结构更加松散,单细胞的数日增多,并凡细胞的形态也符异.     

Effect of La(NO3)3 on the Physiological Indices of Cold Tolerance in Livistona chinensis Seedlings

用0、100、200、300、400、500、600 mg/L硝酸镧溶液喷施蒲葵幼苗叶片作为处理,每天喷施1次,连续3d.在20、5、12和10℃下分别处理24h后测定叶片的丙二醛、可溶性糖和叶绿素含量以及叶绿素a/b的比值.结果表明:硝酸镧溶液处理的幼苗丙二醛含量都比对照低,而且随温度变化幅度小,而可溶性糖和叶绿素含量及叶绿素a/b比值均比对照高.硝酸镧处理可有效改善上述蒲葵幼苗的耐寒性生理指标,其中300 mg/L硝酸镧溶液对提高蒲葵幼苗的耐寒性生理指标具有显著的效应.