长爪沙鼠对植物血凝素的反应及能量学代价的性别和季节差异

以野生长爪沙鼠为对象,通过外源注射植物血凝素(Phytohemagglutinin,PHA)和磷酸盐缓冲液,分别测定了夏季和冬季沙鼠注射前、注射24 h 和48 h 后体重和静止代谢率(Resting metabolic rate,RMR)的变化,以及48 h 后沙鼠足增重量和白细胞总数(White blood cell counts,WBCs)的变化,以检测沙鼠的免疫功能和能量代价的性别和季节差异。结果显示:1)注射PHA 能显著增加沙鼠足重和白细胞的总数,夏季白细胞的总数高
于冬季;2)冬季沙鼠体重高于夏季,雄鼠大于雌鼠,但PHA 处理对注射前后沙鼠的体重无影响;3)冬季RMR高于夏季,雄鼠大于雌鼠,但PHA 处理对沙鼠的RMR 无影响,PHA 处理对注射前后沙鼠的RMR 也无影响。这些结果表明,长爪沙鼠对PHA 的反应具有季节差异,但无性别差异,也没有发现明显的能量学代价,这可能与野外环境条件的大幅度波动(如环境温度和食物条件等)和沙鼠的繁殖状态有关。     

枇杷叶片愈伤组织的诱导与保存

在不同成熟度的枇杷叶片中,最适宜诱导愈伤组织的是中度成熟叶;最适合的愈伤组织诱导培养基是MS+6-BA 1.0mg/L+2,4-D 0.5mg/L,诱导出的愈伤组织为黄绿色、颗粒状、硬度适中;适合愈伤组织继代保存的培养基为MS+6-BA 0.5~1.0mg/L+2,4-D 0.1~0.2mg/L。     

基于竞争和扩散能力的非捕食-被捕食集合种群系统的竞争机制

对于非捕食 被捕食(食饵)生态系统,强弱物种之间存在一定的竞争影响.在不考虑栖息地毁坏的情况下,引进双向竞争机制,将Tilman的单向竞争模式推广为n集合种群双向竞争模型,并对6-集合种群的竞争动态进行了计算机模拟研究.结果表明,在平衡态,种群竞争共存的条件是其竞争能力与扩散能力呈现指数型负相关关系,竞争的结果使物种的强弱序列发生变化;物种竞争排除与共存受迁移扩散能力和竞争能力影响很大,在局域斑块上竞争排斥的集合种群在广域尺度上可以竞争共存,即逃亡共存.     

白菜与甘蓝之间体细胞杂交种获得与遗传特性鉴定

为拓宽白菜育种的基因资源,改良白菜品质,以白菜(Brassica campestris,2n=20,AA)和甘蓝(B.oleracea L.var.capitata,2n=18,CC)的子叶和下胚轴为材料分离、制备原生质体。采用40%聚乙二醇(Polyethylene glycol,PEG)进行原生质体融合。融合细胞在以0.3 mol/L蔗糖、0.3 mol/L葡萄糖为渗透稳定剂,附加1.0 mg/L 2,4-D+0.5 mg/L 6-苄氨基嘌呤(6-BA)+0.1 mg/L 1-萘乙酸(NAA)+1.0 mg/L激动素(Kinetin,Kin)的改良K8p培养基中培养并诱导细胞分裂。小愈伤组织经增殖培养后在MS+0.2 mg/L玉米素(Zeatin,ZEA)+1 mg/L 6-BA+0.5 mg/L Kin+0.4 mg/L NAA的固体分化培养基上诱导出不定芽。30 d后再转入MS基本培养基,获得完整的再生植株。将生根的植株转移到花盆,并对其杂种性质进行形态学、细胞学和分子生物学鉴定。结果表明,经细胞融合分裂出的320个愈伤组织中,获得了35棵再生植株,其再生率达10.94%。形态学观察显示,绝大多数再生植株的叶面积较大,株型和叶型为两种杂交亲本的中间型,部分植株的叶片浓绿、肥厚。染色体计数结果显示,36.4%的再生植株染色体数为2n=38;36.4%的再生植株的染色体数为2n=58 60;27.2%的再生植株的染色体数为2n=70 76,超过两个融合亲本的染色体数的总和。流式细胞仪测定DNA含量显示,再生植株DNA含量变化比较大,其结果与染色体鉴定结果相吻合。随机扩增多态性DNA(Randomamplified polymorphic DNA,RAPD)和基因组原位杂交(Genomic in situ hybridization,GISH)分析结果证明再生植株具有双亲基因组。体细胞杂种花粉育性比较低,杂交、回交后其育性逐渐获得恢复,与白菜回交后代逐渐恢复了育性。通过体细胞杂交和回交、杂交获得了形态变化广泛的个体,为白菜的品种育种提供多样的种质资源。     

Protoplast isolation and culture for somatic hybridisation of rapid cycling <Emphasis Type="Italic">Brassica rapa</Emphasis> with ‘Anand’ CMS and <Emphasis Type="Italic">Brassica juncea</Emphasis>

Protoplasts were isolated from the young leaves of rapid cycling Brassica rapa and cotyledons and hypocotyls of 10-day-old Brassica juncea seedlings. Protoplasts were fused by 40% polyethylene glycol and cultured in modified K8p medium supplemented with 2.5 mg·l⁻¹ isopentenyladenine (2ip), 0.5 mg·l⁻¹ naphthaleneacetic acid, 1 mg·l⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D), 0.1 mg·l⁻¹ zeatin, 1% dimethyl sulfoxide, and 0.4 M mannitol as osmoticum. After 3 days of initial culture, 3 different culture methods were employed and evaluated. The highest plating efficiency (1.97%) was obtained with a semi-solid agarose embedding culture method. Both shoots and somatic embryos formed from protoplast culture-derived calli. The somatic embryos were derived from asymmetrically divided calli that developed progressively into deep-purple heart shapes as well as the early-torpedo and bipolar stages to finally form complete plantlets. Thirteen putative somatic hybrids were produced via somatic embryogenesis or organogenesis. Random amplified polymorphism DNA analysis was performed to identify somatic hybrids. Six regenerated plants had a chromosome number of 2n = 56 the same as the sum of B. juncea (2n = 36) and B. rapa (2n = 20) chromosomes; 2 plants had a chromosome number of 2n = 54. These regenerated plants exhibited morphology intermediate to those of their parents. The flowers of somatic hybrids exhibited a range of variation; some were normal, while others were abnormal. No pollen was produced from regenerated plants. Two plants had crinkled petal-like stamens.     

中国滑刃属一新种记述(滑刃目,滑刃科)

2001～2002年从山东省青州市韭菜Allium tuberosum的根际土壤中发现滑刃属Aphelenchoides1新种,定名为韭菜滑刃线虫Aphelenchoides alliussp.nov.。该虫具有以下特征:虫体大型;唇区缢缩,口针较长,无口针基部球;侧区具有6条侧线;生殖系统发育良好,卵巢具1～2个转折,卵母细胞单列;尾细锥形,末端收缩呈细指状,平截,刺状尾尖突生于其上;雄虫常见,尾钩状,末端具刺状尾尖突,交合刺典型,顶尖和喙突明显。已报道种中有8个种与新种相似,其中5个种虫体体长较短,小于500μm,易与新种分开,它们是:细尖滑刃线虫A.conimucronatus(L=280～440μm),高头滑刃线虫A.editocaputis(L=270～320μm),高山滑刃线虫A.montanus(L=390～400μm),稀少滑刃线虫A.rarus(L=300～320μm),沃恩滑刃线虫A.vaughani(L=360～430μm)。另3个种与新种相比较:中心滑刃线虫A.centralis侧线4条,尾巴较长,雄虫不常见;陶比恰滑刃线虫A.daubichaensis侧线4条,口针较短且有小的基部球,后阴子宫囊较短,卵巢无转折;一点红滑刃线虫A.emiliae口针基部球发达,中食道球椭圆形,更大19μm×15μm,后阴子宫囊较短。     

浙江土壤中的暗色丝孢菌研究Ⅰ.

从浙江省采集的42份土壤样品中,分离出50个暗色丝孢菌分离物,鉴定为26属39种.其中拟苍白弯孢Curvularia subpallescens为新种.侧多隔孢属Pleurophragmium,疣瓶孢属Eladia,拟葡萄孢属Pseudobotrytis和棘瓶孢属Echinobotryum为中国新记录属.鞘孢霉Chalara state of Ceratocystis adiposa,紫棕毛束霉Doratomyces purpureofuscus,黑棘瓶孢Echinobotryum atrum,小囊疣瓶孢Eladia saccula,隘缩小内多隔孢Endophragmiella constricta,青霉状粘束孢Graphium penicillioides,黑侧多隔孢Pleurophragmium actum,土栖拟葡萄孢Pseudobotrytis terrestris,腐植齿梗孢Scolecobasidium humicola和虎尾兰葡萄穗霉Stachybotrys sansevierae为中国新记录种.其余28种为国内已报道种.     

Overexpression of DnaK from a halotolerant cyanobacterium Aphanothece halophytica acquires resistance to salt stress in transgenic tobacco plants

To test the role of the heat shock protein DnaK/Hsp70 in salt tolerance, transgenic plants of Nicotina tabacum cv Petit Havana SR1 were made with DnaK1 from a halotolerant cyanobacterium Aphanothece halophytica (A. halophytica) overexpressed in the cytosol. The growth rate and photosynthetic activities of the transgenic and control tobacco plants were similar under non-stressed conditions. The CO₂ assimilation rate of the control plants decreased with increasing concentration of NaCl. After 3 days of treatment with 0.6 M NaCl, the CO₂ fixation rate decreased to 40% of that in the non-stressed plants whereas its activity in the transgenic plants was about 85% of that in the non-stressed plants. Similar results were observed for the stomatal transpiration. The sodium contents in leaves of the control plants were significantly increased by salt stress whereas those in the transgenic plants remained at levels similar to those in the non-stressed plants. Total protein contents and ribulose 1,5-bis phosphate carboxygenase and oxygenase (RuBisCO) levels were decreased by salt stress in both the transgenic and control plants but the decrease was slight in the transgenic tobacco. All these data clearly indicate that the expression of DnaK1 from a halotolerant cyanobacterium A. halophytica improved the salt tolerance of the tobacco plant.