郑和一号船舶引航系统的设计与实现

为提高引航调度工作效率,保障引航船舶操纵工作更加安全,通过分析引航业务实际需求,采用了基于高分辨率影像、PDA（Personal Digital Assistant）嵌入式、WIFI（Wireless Fidelity）和GPRS（General Packet Radio Service）通讯等先进技术,构成了郑和一号船舶引航系统.该系统为船舶引航工作提供了更加直观的调度平台和航行导航设备.系统通过公网（Internet）或局域网（LAN）的网络通讯接收来自AIS通讯服务端传来的海域内所有船舶动态信息,实时在系统海图窗口中更新显示,同时为用户提供了基于多比例尺电子海图或多分辨率遥感影像,并可叠加航道、航标、锚地、泊位、地名以及水深点等多维助航要素数据,进行显示、查询、监控等操作功能,从而为船舶引航调度提供辅助支持.     

两栖蔊菜种群及其入侵群落特征

两栖蔊菜(Rorippa amphibia)是近年来备受关注的入侵植物,主要出现在草坪中,并有不断向各种生境扩张的趋势,往往会成为其入侵群落中的优势种,因此研究其种群和群落特征及环境影响因素,对于更好地了解其入侵机制具有重要理论意义。本研究调查了不同小生境中受到两栖蔊菜入侵的草坪群落,采用扩散系数(C)、负二项参数(K)、平均拥挤度(m*)、丛生指标(I)、聚块性指标(PI)、Cassie指标(CA)和Green指数(GI) 7个指标对两栖蔊菜的空间分布格局进行研究,并分析两栖蔊菜的种群密度、盖度等特征。运用聚类分析、主成分分析(PCA)探讨了群落类型的差异及主要环境影响因子。结果表明,在不同生境条件下两栖蔊菜种群均呈聚集分布。无遮阴和半遮阴条件下,两栖蔊菜的种群密度分别为全遮阴条件的2.93倍和2.73倍,盖度分别为4.52倍和4.79倍,高度分别为1.57倍和2.37倍。即在全遮阴条件下两栖蔊菜种群的密度、高度、盖度均最低,且与无遮阴生境种群间差异显著(P <0.05);半遮阴条件下,两栖蔊菜的高度和盖度最高,与全遮阴生境下差异显著(P <0.05),与无遮阴生境种群高...     

4株Ⅰ亚群禽腺病毒分离株对SPF雏鸡的致病性研究

【目的】 探究Ⅰ亚群禽腺病毒（Fowl adenovirus,FAdV）分离株GDDL-4（FAdV-4）、GDB3-8a （FAdV-8a）、GDT08-8b （FAdV-8b）、GDWYT-11（FAdV-11）对SPF雏鸡的致病性,进而制定更加有效的防控措施。【方法】 设立4个攻毒组（GDDL-4、GDB3-8a、GDT08-8b、GDWYT-11）及对照组,攻毒组选择腿部肌内注射接种0.2 mL 10⁵ TCID₅₀病毒液,对照组接种等体积PBS。接种后观察SPF雏鸡的临床症状、剖检病变及组织病理学变化,同时检测其排毒量和病毒载量。【结果】 所有攻毒组鸡均表现为精神沉郁、消瘦、扎堆等,病理剖检以严重心包积液-包涵体肝炎综合征病变为主,其中GDDL-4组症状最为严重,死亡率最高达85%,总体死亡率在0~85%之间。排毒分析结果发现,GDDL-4和GDB3-8a组出现高滴度排毒（≥10⁴拷贝/μL）,GDT08-8b和GDWYT-11组仅能检测到低滴度（≤10³拷贝/μL）排毒。器官指数表明,除GDT08-8b组与对照组无明显差异外,其余攻毒组均能造成器官不同程度的肿大或萎缩。病理组织学切片显示,肝脏、肾脏、法氏囊的正常结构被破坏,可见肝细胞有大量淋巴细胞浸润、肾间质充血出血、法氏囊淋巴细胞坏死等。病毒载量分析结果显示,GDDL-4与GDWYT-11组在肝脏组织中病毒滴度最高,而GDB3-8a与GDT08-8b组在十二指肠中病毒滴度最高。【结论】 Ⅰ亚群FAdV的死亡率高,4株分离株均可导致雏鸡肝脏出现包涵体肝炎的病理变化,均可反复排毒,且分离株对不同的组织器官有不同的亲嗜性,在肝脏与十二指肠等组织中的病毒载量最高。     

紫荆光合日进程及光响应

自然条件下使用LCA-4型便携式光合测定系统研究了紫荆连体叶片的光合日变化及光响应。结果表明:(1)净光合速率的日进程曲线呈“双峰”型,胞间CO2浓度的日进程基本与净光合速率相反,中午胞间CO2浓度增高,表明净光合速率午间降低主要受非气孔限制因素的影响。暗呼吸速率日进程为单峰曲线,中午最高。气孔阻力的日变化曲线是单谷型,午间最低。(2)一天分时段光响应试验表明,饱和光强和表观量子效率上午最高,中午最低,下午有所上升。下午的光补偿点是上午的2倍,中午则是上午的近3倍。不同时段遮光都使得气孔阻力和胞间CO2浓度升高。     

次生幼龄林封山育林后乔木层物种结构变化研究

1999年在浙江省仙居县俞坑村的封山育林区设置20 m×20 m的固定样地2块,对连续5年的调查数据进行统计分析,以其对次生幼林乔木物种结构变化进行研究.分析结果,乔木层物种丰富度指数增加了7～11,乔木物种增加了2～5科,3～8属.自然恢复为以壳斗科、杉科、山茶科、樟科、胡桃科、安息香科等物种为建群种或共建种的次生常绿阔叶林、针阔混交林.     

水分胁迫对云锦杜鹃光合特性日变化的影响

以盆栽5年生云锦杜鹃苗木为材料,分对照、轻度胁迫、中度胁迫、重度胁迫4组,研究了土壤水分胁迫对云锦杜鹃叶片光合特性日变化的影响。结果表明:随着水分胁迫的加重,云锦杜鹃的光合日变化曲线由典型的双峰型逐渐转变为峰值很小的单峰型,峰值的降低在轻度水分胁迫下由气孔限制引起,而在中度和重度水分胁迫下则由非气孔限制引起。轻度、中度和重度水分胁迫对云锦杜鹃光合特性日变化的影响差异显著。经逐步多元回归得到了净光合速率日变化的回归方程。     

Nitrogen mobilization, nitrogen uptake and growth of cuttings obtained from poplar stock plants grown in different N regimes and sprayed with urea in autumn

Nitrogen mobilization, nitrogen uptake and growth of cuttings obtained from poplar stock plants fertigated with different nitrogen (N) treatments and sprayed with urea in autumn were studied. Stock plants propagated from poplar cuttings were trained to a single shoot and fertigated with 0, 5, 10, 15 or 20 mmol l(-1) N during the first growing season. In October, a subset of stock plants from each N fertigation treatment was sprayed twice with either 3% urea or water, and overwintered outside. In March, total tree biomass and total N concentration and content of stems were estimated for stock plants in each treatment, and cuttings were taken from the middle of each stock plant and stored in plastic bags at 2 degrees C. In mid-April, cuttings were planted in 7.5-l pots containing N-free medium and grown outdoors with a weekly fertigation with nutrient solution containing 0 or 10 mmol l(-1) 15NH4 15NO3. In mid-July, cuttings were harvested, and new shoot (new stems and leaves), shank (old cutting stem) and roots were analyzed for new biomass growth and total N and 15N content. Growth of stock plants was positively related to N supply in the previous growing season. Foliar urea application in autumn had no effect on subsequent stock plant growth even though urea sprays increased both N concentration and content in stem tissues. Biomass growth of cuttings obtained from stock plants was closely related to their N content when the cuttings were grown in an N-free medium regardless of previous treatments applied to the stock plants. When N was supplied in the growth medium, the strength of the relationship between regrowth and N content of cuttings was significantly reduced. Cuttings from stock plants treated with foliar urea and grown in a N-free medium remobilized between 75 and 82% of their total N for new growth, whereas cuttings from plants receiving no urea spray remobilized only between 60 and 69% of their total N for new growth. Current N fertilization of the cuttings reduced the percentage of N remobilized. We conclude that new growth of poplar cuttings in spring was more dependent on currently applied N than on reserve N, and urea N applied as a spray in autumn was more easily remobilized than N taken up by roots during the previous season.     

部分放开森林采伐限额政策探讨

通过分析不同森林类型采伐的经营特点,探讨森林采伐限额政策的适宜程度,形成对部分类型森林放开采伐限额的思路,分析评估放开采伐限额政策的风险,提出改善森林采伐限额政策建议。     

不同核背景对玉米CMS-C线粒体复合体活性的影响

为探究不同核背景下线粒体复合体活性对玉米C型雄性不育系育性的影响,明确其与花药败育的关系.以同质异核不育系K932S、K169S、近等基因恢复系K932R和保持系K169为材料,采用植物线粒体呼吸链复合体酶联免疫分析试剂盒对花药发育不同时期的5个线粒体复合体活性进行测定比较.结果表明,除花粉母细胞时期复合体Ⅱ、Ⅳ外,其余时期不育细胞质复合体Ⅰ、Ⅱ、Ⅳ活性在K169核背景下显著高于K932,绝大多数时期复合体Ⅲ、Ⅴ的活性则相反,但存在恢复基因时,K932R可改变部分时期不育细胞质不同线粒体复合体的活性.在二分体时期,不育细胞质复合体Ⅱ、Ⅲ、Ⅴ活性显著低于正常可育胞质,而其他多数时期5个复合体的活性则相反.由此可见,在花药发育不同时期,核背景对玉米CMS-C不同线粒体复合体活性均有显著影响;相同核背景下,二分体时期不育细胞质复合体Ⅱ、Ⅲ、Ⅴ活性比正常细胞质显著降低,可能与CMS-C花药败育密切相关.     

Soybean mosaic virus Helper Component-Protease Alters Leaf Morphology and Reduces Seed Production in Transgenic Soybean Plants

ABSTRACT Transgenic soybean (Glycine max) plants expressing Soybean mosaic virus (SMV) helper component-protease (HC-Pro) showed altered vegetative and reproductive phenotypes and responses to SMV infection. When inoculated with SMV, transgenic plants expressing the lowest level of HC-Pro mRNA and those transformed with the vector alone initially showed mild SMV symptoms. Plants that accumulated the highest level of SMV HC-Pro mRNA showed very severe SMV symptoms initially, but after 2 weeks symptoms disappeared, and SMV titers were greatly reduced. Analysis of SMV RNA abundance over time with region-specific probes showed that the HC-Pro region of the SMV genome was degraded before the coat protein region. Transgenic soybean plants that expressed SMV HC-Pro showed dose-dependent alterations in unifoliate leaf morphologies and seed production where plants expressing the highest levels of HC-Pro had the most deformed leaves and the lowest seed production. Accumulation of microRNAs (miRNAs) and mRNAs putatively targeted by miRNAs was analyzed in leaves and flowers of healthy, HC-Pro-transgenic, and SMV-infected plants. Neither expression of SMV HC-Pro nor SMV infection produced greater than twofold changes in accumulation of six miRNAs. In contrast, SMV infection was associated with twofold or greater increases in the accumulation of four of seven miRNA-targeted mRNAs tested.