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1.
A petrified strobilus Discinites sinensis sp.nov.is discovered from the Lower Permian of Shizuishan in Ningxia,North China.The epidermal cells of sporophyll are long and narrow,with both ends pointed.Each sporangium is ellipsoid,with the basal part contracted and short,thick sporangiophore-like.The cells of tapetum and sporangial walls are arranged longitudinally.The annulus is not developed.Mega- and microsporangia are similar in shape.They can hardly be distinguished unless they are broken,and the spores are exposed.In situ mega- and microspores are also similar in shape and both of the Deltoidospora type.The new species supports the systematic placement of Discinites within Noeggerathiales,and the progymnosperm affinity of the Noeggerathiales.  相似文献   

2.
A number of specimens recently collected from the Early Permian Shanxi Formation of Wuda, Inner Mongolia demonstrate that the leafy shoot and strobilus of Tingia unita sp. nov. are both sprouting from a common stem, and consequently improve our understanding of the whole plant mor- phology of this enigmatic taxon of the Cathaysian flora. The strobili are cylinder-like, 1.7-2.5 cm in diameter and over 20 cm in length, with a basal stalk 7―8 mm in width and about 7 cm long. Sporophylls are verticillate, with approximately 8-10 in a whorl. On the adaxial side of each sporophyll a sporangium is attached. The strobilus is heterosporous and the microspores are of the Punctatisporites type. Large leaves vary from linear to oblong with entire lateral margins but are slightly lobed at the apex. Small leaves are generally the same as the large leaves but much narrower. The whole plant is probably a small arborescent tree with leafy shoots and strobili forming a crown, rather than a water plant with larger leaves floating on the surface of the water as previously understood. Features of the new species are in favor of the close affinity between Tingia Halle and Noeg- gerathiales, and accordingly the affinity of Noeg- gerathiales to Progymnospermophyta.  相似文献   

3.
Noeggerathiales are an extinct group of sporebearing plants of uncertain systematic position that are known from Carboniferous and Permian age Euramerican and Cathaysian floras that occurred in presentday Europe, North America, and East Asia. The order Noeggerathiales includes over 50 species of more than 20 fossil genera, but their paleoecology is not well understood yet. Previously this group had been found only in extrabasinal floras or those inhabiting clastic wetlands. Noeggerathiales have never been recorded in coal ball floras. Thus, it is up to now uncertain whether this group has contributed to the formation of coal. Recent investigations of an Early Permian peatforming flora of the Taiyuan Formation near Wuda, Inner Mongolia, which was preserved in a volcanic ash fall has provided evidence that noeggerathialean plants not only existed in the peatforming vegetation but could even be the dominant group in some areas of the coal swamp. The Noeggerathiales in this particular peatforming forest include Tingia unita, Paratingia wudensis, and a new species of Paratingia. Exceptionally well-preserved specimens indicate that these noeggerathialean plants are small trees with a canopy of compound leaves and strobili near the top of an unbranched (monocaulous) stem.  相似文献   

4.
The substructure of pollen exine inCedrus deodara (Roxb.) Loud. andMetasequoia glyptostroboides Hu et Cheng has been examined with an atomic force microscope (AFM). The results indicate that the exine substructure units containing sporopollenin in two species are similar in shape, which are granular, but slightly different in size. InCedrus the substructure unit of pollen exine appears to be 56–99 nm long and 42–74 nm wide, while inMetasequoia it appears to be 81–118 nm long and 43–98 nm wide. It has been observed that the subunits of pollen exine inCedrus arranged tightly to form short-rod-like or spheroidal pollen exine units, several or more than ten of which formed an island-like structure. There are various spaces among these island-like structures which are interconnected to occupy the entire pollen exine. InMetasequoia, the subunits of pollen exine also arranged tightly with a distribution tendency of cluster of 3–10, however, no obvious boundary exists among these clusters. From our results, it is concluded that there is no tendency of helical arrangement for the subunits of pollen exine inCedrus andMetasequoia, and the results support Southworth’ view that subunits of pollen exine are granular shape in lattice structure.  相似文献   

5.
The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) belongs to the eIF2α kinase family and plays a critical role in interferon (IFN)-mediated antiviral response. Recently, in Japanese flounder (Paralichthys olivaceus), a PKR gene has been identified. In this study, we showed that PoPKR localized to the cytoplasm, and the dsRNA-binding motifs (dsRBMs) played a determinative role in protein localization. In cultured FEC cells, PoPKR was detected at a low level of constitutive expression but was highly induced after treatment with UV-inactivated grass carp hemorrhagic virus, active SMRV and Poly I:C although with different expression kinetics. In flounder, PoPKR was ubiquitously distributed in all tested tissues, and SMRV infection resulted in significant upregulation at mRNA and protein levels. In order to reveal the role of PoPKR in host antiviral response, its expression upon exposure to various inducers was characterized and further compared with that of PoHRI, which is another eIF2α kinase of flounder. Interestingly, expression comparison revealed that all inducers stimulated upregulation of PoHRI in cultured flounder embryonic cells and fish, with a similar kinetics to PoPKR but to a less extent. These results suggest that, during antiviral immune response, both flounder eIF2α kinases might play similar roles and that PoPKR is the predominant kinase.  相似文献   

6.
目的对马鞭草科莸属植物兰香草的显微特征进行研究。方法采用石蜡切片、表皮制片、解离组织片对药材的茎、叶横切面组织结构进行研究,粉末制片对全草粉末进行显微鉴定。结果茎横切面可见表皮被有多数非腺毛及腺毛,木质部及髓部宽广。叶横切面中主脉维管束1~3个,上表皮下厚角组织不明显,韧皮部细胞较小排列紧密。粉末中可见叶上下表皮细胞垂周壁弯曲,气孔不定式,同时可见黏液细胞、非腺毛、腺毛、导管等。结论上述显微特征可作为兰香草的显微鉴定依据。  相似文献   

7.
The violaxanthin de-epoxidase gene was cloned from rice (Oryza sauva subsp japonica). The full length of the cDNA is 1887 bp, encoding a 446-amino acids protein with the transit peptide of 98 amino acids. The bacterial expression vector pET-Rvde was constructed and the expression quantity of the exogenous protein increased with the induction time by 0.4 mmol/L IPTG. Its molecular weight was similar with that of the native VDE. Western blotting indicated that the expressed protein has immunological reaction with the VDE polyclonal antibody. The absorbance spectrum together with xanthophyll pigments quantification by HPLC demonstrated that the expressed VDE has its enzyme activity, which can de-epoxidate violaxanthin into antheraxanthin and zeaxanthin in vitro.  相似文献   

8.
A scanning electron microscope observation is carried out on Glycine soja L., which grows around the estuary of the Yellow River, in Kenli County, Shandong Province. It is first discovered that there are salt glands, in the shape of balls, on the surface of the stems and leaves of G. soja L., and distributed at the intercellular layer. With a handle at the base, the salt glands are not equal in size, and show a layer-upon-layer structure. They have a diameter of 21.6 μm, a handle length of 1.2 μm, their secretory pore's diameter is 5.6 μm. There are two ways to secrete salt ions: younger glands secrete salt ions through the secretory pore, and mature glands by breaking themselves.  相似文献   

9.
Ichthyosaur from Guizhou, China   总被引:9,自引:0,他引:9  
Chun Li 《科学通报(英文版)》1999,44(14):1329-1329
A new ichthyosaur is named and described on the basis of two well-preserved skeletons from the Late Triassic Wayao Member of Falang Formation, Guizhou Province, southwestern China. The specimens represent a longipinnate ichthyosaur with a set of characters transitional from the Triassic forms to the Jurassic forms. It is similar to shastasaurids of the Triassic in the relative size and shape of the limbs but resemblesOphthalmosaurus andBaptanodon of the Jurassic in the shape of the skull. The new taxon differs from all other ichthyosaurs found in China in its unusual large orbit, distinct rostrum, and the hind limbs, that are slightly stronger than the fore ones.  相似文献   

10.
梁俊勋 《广西科学》1998,5(2):156-160
在45m2室内人工模拟自然条件下进行褐家鼠和黄胸鼠取食行为生态学特征的研究。观察结果显示,两种鼠对所提供的食物的日平均取食量和觅食时所付出的活动行为强度均无明显差异,但在日内的7时、15时和23时之间的摄食量和活动量的差异均极显著。当所提供的食物源有选择机会时,褐家鼠选择的平均取食量是玉米碎>稻谷>大米;黄胸鼠是玉米碎>大米>稻谷,无食物选择机会时褐家鼠的取食量是稻谷>玉米碎>大米;黄胸鼠是大米>玉米碎>稻谷。褐家鼠和黄胸鼠在寻找选择食物的过程中,通常付出的活动行为强度(量)是23时点>7时点>15时点。褐家鼠和黄胸鼠的取食行为特征表现可用“摄食时间+食物源+行为反应”的模式表示。同时指出鼠的取食行为与防治实践之间关系的重要性。  相似文献   

11.
为了进一步弄清桂西北种植光皮桦(Betula luminfera)的生长量,于1997年4月在广西林朵林场营造光皮桦人工纯林,与马尾松纯林进行对比研究,结果表明:3.5年生光皮桦林分的平均树高、平均胸径和平均蓄积量分别为7.42 m、7.50 cm和30.06 m3·hm-2,分别比同龄马尾松林分的平均高(4.58m)、平均胸径(4.96cm)、平均蓄积(18.193m3/hm2)提高62.0%、51.2%和65.3%。说明该区营造光皮桦人工幼林的生长量较大,建议在相似立地条件下局部推广营造光皮桦人工林。  相似文献   

12.
韦柳静  卢磊芳 《广西科学》2018,25(3):339-342
【目的】氧化葡萄糖酸杆菌是一种严格好氧的革兰氏阴性菌,能够立体选择性氧化多种羟基化合物生成相应的醛、酮或酸。【方法】本文将比较两株氧化葡萄糖酸杆菌DSM 2003和621H的静息细胞对甘油、乙二醇及乙醇的催化能力,并研究了溶氧对催化反应的影响。【结果】两株氧化葡萄糖酸杆菌氧化甘油的能力较相似,溶氧对这两株菌的甘油催化能力都有较大影响;氧化葡萄糖酸杆菌DSM 2003能够将乙二醇几乎全部氧化为羟基乙酸,副产物少,而621H转化相同量的底物只生成较少量的羟基乙酸,副产物多。氧化葡萄糖酸杆菌621H生产乙酸的能力也很低。【结论】两株氧化葡萄糖酸杆菌催化甘油生成二羟基丙酮的能力相当,但在催化醇生成酸的反应中,氧化葡萄糖酸杆菌DSM 2003更具优势。  相似文献   

13.
A Palaeozoic gleicheniaceous fernOligocarpia kepingensis sp. nov. is described from the Lower Permian of the northern Tarim Basin, Xinjiang, China. The material comprises fertile organs including sori, sporangia, spores and associated sterile leaf of theSphenopteris type. The sori are circular and 0.6–0.8 mm in diameter, and each sorus consists of 4–6 oval sporangia without an indusium. A transverse annulus completely encircles the sporangium. Each sporangium produces probably 256 trilete spores resembling the dispersed genusLeiotriletes. Comparisons are made betweenO. kepingensis and other species ofOligocarpia in the soral organization and spores. It is reasonable to includeOligocarpia in Gleicheniaceae based on its similarities of fertile character to the extant gleicheniaceous members.  相似文献   

14.
【目的】水产养殖业的快速发展和鱼油价格的快速上涨,使得寻找能够替代鱼油的脂肪源日趋紧迫。【方法】采用直接转酯化进行气相色谱鉴定的方法测定鱼油、多种常见植物油和两种微藻的脂肪酸组成,以37种脂肪酸标准品作为参照,比较分析3类脂肪源的异同。【结果】鱼油的脂肪酸组成与微绿球藻(Nannochloropsis sp.)和裂壶藻(Schizochytriumsp.)相似,但植物油与鱼油相比缺乏EPA和DHA等n?3高不饱和脂肪酸。在满足必需脂肪酸需求的前提下,提出两种替代鱼油的策略:1使用38.0%亚麻籽油配合27.7%微绿球藻藻油和34.3%裂壶藻藻油替代鱼油的策略获得与鱼油一致的n?3/n?6多不饱和脂肪酸比率,能够较好地满足鱼类的营养需求,可作为替代鱼油的首选策略;2使用38.0%大豆油配合27.7%微绿球藻藻油和34.3%裂壶藻藻油替代鱼油的策略则获得与鱼油大体相同的主要脂肪酸类别,价格较亚麻籽油组低廉,可作为备选策略。【结论】使用高EPA和DHA含量的微藻藻油配合植物油替代鱼油在理论上是可行的。  相似文献   

15.
萘对铜绿微囊藻和聚球藻生长及叶绿素荧光影响的比较   总被引:1,自引:0,他引:1  
为探究萘对不同粒径蓝藻的胁迫效应,采用5组不同质量浓度萘(0、0.01 mg/L、0.1 mg/L、1 mg/L、10 mg/L)分别对聚球藻(Synechococcus sp.)和铜绿微囊藻(Microcystis aeruginosa,PCC7806)进行为期7 d的处理,分析不同浓度萘处理下,藻细胞浓度、叶绿素a含量及叶绿素荧光参数的变化,探究不同浓度萘处理对2种藻的生长及生理影响。结果表明:(a)整个处理周期内,聚球藻的生长被显著抑制,其叶绿素a含量减小了3.9%~40.4%;(b)聚球藻的潜在光合作用能力、光合作用速率均有所减弱,但其耐受强光的能力有所增强,说明聚球藻对萘具有较强的敏感性;(c)萘对铜绿微囊藻生长具有显著的促进作用,增强了其潜在光合作用能力,但抑制了其细胞内叶绿素a的合成。  相似文献   

16.
The fusion gene of actin (cDNA ofChlamydomonas reinhardtii) and green fluorescence protein (gfp) had been constructed into two expression vectors which could be expressed inE. coli and tobacco suspension cells BY2. The correct expression was observed inE. coli and BY2 with a fluorescence microscopy. The fusion protein, which took part in the membrane skeleton, was mainly located peripherally along the membrane, specially the fusion protein was distributed around nucleus and cell plate, while the fusion protein also forms F-actin in the cell. The fusion protein was purified from Bl21plus by ammonium sulfate fractionation, ion exchange chromatography and hydrophobic interaction chromatography. The purified production could polymerize into F-actin when the actin polymerizing buffer was added. It was demonstrated that the characteristics and function of actin inChlamydomonas was similar with those of animals and higher plants.  相似文献   

17.
八宝景天叶片表面润湿性测试与疏水机理分析   总被引:1,自引:0,他引:1       下载免费PDF全文
为探寻用于超疏水表面制备的仿生原型,测试了八宝景天(Hylotelephium erythrostictum)叶片表面对水滴的润湿性,采用扫描电镜和三维形貌干涉仪对叶片表面微形貌结构进行观测并提取特征参数,基于Wenzel方程和Cassie-Baxter方程构建模型用以分析叶片表面的疏水机理。结果表明:润湿性随叶片类型的不同而呈现差异,其中新鲜幼叶正、反表面的接触角分别为(147.25±3.79)°和(137.46±4.03)°,新鲜幼叶反面的接触角高达152.54°;叶片表面由排列连续致密且呈椭球形的凸包和交错排列成网状且形貌不规则但可辨别轮廓的蜡质晶体构成,不同类型叶片表面的凸包形貌呈现显著差异但蜡质晶体形貌未有明显区别;幼叶正、反表面的凸包具有相似的高度但分布密度和投影面积显著不同,蜡质晶体层的高度和面积比未有明显差异;微米级凸包和纳米级蜡质晶体的协同作用使叶片表面呈现疏水特性且蜡质晶体发挥关键作用。基于Cassie-Baxter方程构建的模型能够有效揭示叶片表面的疏水机理,并可为超疏水表面的仿生制备提供理论支持。  相似文献   

18.
Acetylcholine (ACh), as an important neurotransmitter in animals, also plays a significant role in various kinds of physiological functions in plants. But relatively little is known about its receptors in plants. A green fluorescence BODIPY FL-labeled ABT, which is a high affinity ligand of muscarinic acetylcholine receptor (mAChR), was used to localize mAChR in plant guard cells. InVicia faba L. andPisum sativum L., mAChR was found both on the plasma membrane of guard cells. mAChR may also be distributed on guard cell chloroplast membrane ofVicia faba L. The evidence that mAChR localizes in the guard cells provides a new possible signal transduction pathway in ACh mediated stomata movement.  相似文献   

19.
20.
广西油茶(Camellia oleifera)资源丰富,种植历史悠久。广西油茶产业虽然初具规模,但是还存在资源质量不高、产业链条不长、品牌建设滞后等突出问题和薄弱环节,需要进一步加大政策支持力度,推动油茶产业早日成为乡村振兴的支柱产业。  相似文献   

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