风廓线雷达资料在沈阳冰雹天气过程中的分析应用

本文利用风廓线雷达的基本产品、Micaps实况资料和区域自动站资料,对沈阳城区发生的一次冰雹天气过程进行分析,结果表明：此次冰雹是在冷涡背景下,高空存在横槽、逆温,触发的局地的强对流天气过程。降雹前高空由西北风转为偏西风,预示着横槽的到来,风廓线雷达对冷空气侵入的判别提前于常规观测资料。1000 m以下水平风的变化与降雹时间及强度有较好的对应。高空水平风速≥12 m/s的风速带在降雹前1h达到峰值。高空急流区在冰雹发生前20~25min出现急流动量下传,为冰雹的产生提供动力条件。降雹阶段探测高度明显增加,主要是由于空气湿度增大和高层存在大量冰晶粒子所致。冰雹过程中,冰晶粒子主要集中在1900 m以下。降雹前25min垂直风切变增大,并在降雹前20min达到极值,垂直风切变的变化与急流的变化相对应。垂直速度达到极值对应的并不是降雹的开始,低层信噪比＞60 dB,对应降雹开始,信噪比对于冰雹的敏感程度比垂直速度高。垂直速度大于4 m/s与降水的开始、结束时间有着很好的对应关系。     

Differential abundance of proteins in response to Beet necrotic yellow vein virus during compatible and incompatible interactions in sugar beet containing Rz1 or Rz2

Rhizomania, caused by Beet necrotic yellow vein virus (BNYVV), is an important disease affecting sugar beet. Control is achieved through planting of resistant varieties; however, following the introduction of Rz1, new pathotypes that overcome resistance have appeared. To understand how BNYVV overcomes resistance, we examined quantitative protein differences during compatible and incompatible interactions when sugar beet is infected with either a traditional A-type strain or with an Rz1 resistance breaking strain. Proteomic data suggest distinct biochemical pathways are induced during compatible and incompatible sugar beet interactions with BNYVV. Pathways including the detoxification of reactive oxygen species, UB/proteasome, and photosynthesis should be studied in more depth to characterize roles in symptom development.     

猪繁殖与呼吸综合征病毒垂直传播及其危害研究进展

猪繁殖与呼吸综合征病毒(PRRSV)感染引起的繁殖障碍在妊娠早期表现为母猪受胎率低、不规律返情及孕早期流产;怀孕后半期流产、早产,产死胎、木乃伊胎及弱仔等。先天感染的仔猪抵抗继发感染的能力低,可持续排毒并感染周围的阴性动物。PRRSV穿过胎盘屏障感染胎儿很可能是经巨噬细胞/单核细胞介导的,并在母胎界面造成病理损伤,病毒在胎儿着床点的复制可能是导致胎儿死亡和母猪流产的原因。预防PRRSV垂直传播必须控制母猪感染PRRSV,缩短已感染母猪的病毒血症持续时间,此外,通过生物安全、限制猪群流动和严格的消毒措施控制水平传播,通过疫苗免疫和药物保健消除易感动物。作者概述了妊娠各阶段母猪感染PRRSV发生垂直传播的情况及其后续的繁殖障碍。     

越夏期不同欧洲鹅耳枥品种耐热性评价

以欧洲鹅耳枥原种(Carpinus betulus)及其4个园艺品种贝克曼（Albert Beekman）、弗兰斯（Frans Fontaine）、卢卡斯（Lucas）、法斯塔（Fastigiata）为试验材料,观察其在南京地区自然越夏的田间性状表现,分析其越夏过程中生理生化指标的变化,并应用隶属函数法和系统聚类法对欧洲鹅耳枥各品种耐热性进行综合评价。综合评价后得出欧洲鹅耳枥各品种耐热性强弱依次为弗兰斯>贝克曼>法斯塔>原种>卢卡斯。热害指数和相对电导率能较好地反映欧洲鹅耳枥耐热性强弱,但部分生理生化指标在越夏期内变化规律性不强,应采用综合评价法进行耐热性比较。欧洲鹅耳枥各品种在南京地区可安全越夏,其耐热性综合评价结果与自然越夏田间性状表现一致。     

木材吸湿机理及其应用

木材是一种多孔性、吸湿性和各向异性的天然高分子材料,水分影响着木材多方面的性质。文中从木材组分的角度综述了木材对水分的吸湿机理,介绍了木材对水分吸附的基本理论,解释了木材吸湿滞后现象的基本原因;在上述基础上评述了降低木材吸湿性的基本方法及其实现原因,还分析了机理应用方面存在的不足以及测试方法的不统一,并对未来研究趋势进行了展望。     

Effect of Heat Stress on the Photosynthetic Characteristics in Flag Leaves at the Grain‐Filling Stage of Different Heat‐Resistant Winter Wheat Varieties

Heat stress has become an increasingly important factor in limiting wheat yields. In northern China, high temperature (>30 °C) during the grain filling is one of the major constraints in increasing wheat productivity. We used two winter wheat (Triticum aestivum L.) cultivars with different sensitivities to heat stress (Jimai 22 ‘JM22’, low sensitivity and Xinmai 26 ‘XM26’, high sensitivity) to study the various aspects of photosynthetic characteristics during the grain filling stage under heat stress. The results showed that photosynthesis rates (P_n) in flag leaves of XM26 decreased faster than in JM22 under heat stress during the grain‐filling stage. P_n decreased more rapidly under heat stress than without stress, by up to 69.9% and 59.3%, respectively, at 10 days following heat stress (10 DAS). This decline of P_n was not caused by heat‐induced stomatal limitation, but rather by a decline in Rubisco activity and a functional drop in photosystem II (PSII). After heat stress, the grain yield of JM22 decreased by 6.41%, but XM26 decreased by 11.43%, when compared with their respective controls. Heat stress also caused an alteration of mesophyll cell ultrastructure. Injury caused by heat stress to organelles in XM26 was more severe than JM22. Moreover, the JM22 cultivar showed some self‐repair capacity following heat stress injury. These results indicate that declines in photosynthetic performance caused by heat stress were cultivar‐dependent. Compared with XM26, the JM22 cultivar had superior heat stability in terms of PSII function and carboxylation activity, both of which are susceptible to heat stress.     

湿地松人工林地径与胸径树高模型的研究

应用样木资料,采用多方程分析对比法建立胸径与地径及树高与地径的相关数学模型,所建立的模型平均相对误差低于2％,预估效果理想,从而为通过地径的测定,应用二元立木材积表测定湿地松人工林被伐木材积提供了科学依据,在实践上有应用价值。     

额济纳旗盆地土壤过氧化氢酶活性的垂向变化研究

土壤过氧化氢酶作为反映土壤生态状况的重要指标少见报道。作者在详细的野外调查及室内分析的基础上 ,介绍了额济纳旗盆地土壤过氧化氢酶研究意义及可行性 ,调查研究的方法 ,并根据土壤过氧化氢酶活性随土剖面深度的变化曲线类型 ,结合当地土壤、植被条件分析了其三种变化模式及原因 ,为当地恢复土壤植被生态系统提供了依据。     

3种生物农药对保护地番茄常见病害的室内药效测定

为了减少使用化学农药带来的环境污染,病害产生抗药性以及番茄的农药残留问题,目前生产上迫切需要生物农药的推广和使用。笔者利用生长速率抑制法测定了3种生物农药对5种常见的保护地番茄病害的室内抑菌作用,测试药剂为植物源杀菌剂:10%霉菌消,60%灰霉散和60%霜霉散。结果表明,3种生物药剂对5种保护地番茄病害均有一定的抑制效果,其中10%霉菌消对番茄早疫病菌的抑制率为63 0%,60%灰霉散对番茄根腐病菌的抑制率为61 1%,60%霜霉散对番茄根腐病菌的抑制率达到76 4%。