The discovery of whole-plant fossil cycad from the Upper Triassic in western Liaoning and its significance

A recently discovered megafossil of whole plant cycad is briefly reported here. The specimen is collected from the Yangcaogou Formation （Upper Triassic） in Changheying, Beipiao, Liaoning. The whole plant is preserved intact on a sandstone slab, 89 cm long and 130 cm wide, including leaves up to 82 cm long and a male cone physically attached to the stem apex. Analysis on the morphology, arrangement and venation of leaf and pinna, male cone and its relationship with other parts indicates that the fossil is closely related to living Zamiaceae in Cycadales. This cycad fossil is hitherto most completely preserved cycad specimen including both vegetative and reproductive organs. Its discovery contributes much to our understanding of the morphology and evolution of cycads, palaeoclimate as well as palaeoenvironment.     

Palaeogene fossil <Emphasis Type="Italic">Populus</Emphasis> leaves from Lanzhou Basin and their palaeoclimatic significance

An angiosperm compression flora is found in Palaeogene from Lanzhou Basin and the cuticular analysis of Populus davidiana Dode in the flora is carefully made. Furthermore, the fossil cuticles are compared with the epidermal structures of extant Populus leaves growing in different environments, i.e. moist, semimoist, and semiarid to arid climatic regions. The present experiments indicate that mature leaves of P. davidiana show leaf size from big to small, leaf cuticles from thick to thin and anticlinal walls of epidermal cells from faintness to clarity along with the increase of lattudes of the plant distributions, the climatic variation from moist to arid, the annual precipitation from more to less and the annual mean temperature from high to low. The fossil P. davidiana differs from the specimens collected from Shandan in semiarid to arid climatic regions but closely resembles the Wushan leaves in a semi-moist climatic area in a lot of features. In a word, the new research may reflect that the flora lives in a semi-moist climatic environment. The present discovery of compression of Paleogene Populus davidiana is of great significance to studying vegetation types, climatic and environmental changes during the primal uplifting of the Qinghai-Tibet Plateau.     

Characterstics of seasonal variations of leaf n-alkanes and n-alkenes in modern higher plants in Qingjiang, Hubei Province, China

On the basis of GC and GC-MS analyses, the seasonal variation of leaf lipids is observed in five plant species in Qingjiang in Hubei Province. The CPI values (carbon preference index) of n-alkanes decrease gradually from May to November, though the carbon number distributions and the predominant carbon number in an individual species keep unchanged. The declined CPI values might be caused by the leaf fading, which is further supported by a comparison of the defoliated leaves with the fresh leaves. This observation infers the CPI values of n-alkanes in Quaternary sediments can be used as a tool to index the humification, and thus the climatic and the environmental conditions. The plants analyzed here show a remarkable difference in n-alkanes abundance, suggesting their differential contribution to the n-alkanes identified in sediments. The abundance and the compound species of the n-alkenes detected in the plant leaves change greatly with the seasons due to the influence of temperature, with the least compounds being identified in August.     

Characterstics of seasonal variations of leaf n-alkanes and n-alkenes in modern higher plants in Qingjiang, Hubei Province, China

On the basis of GC and GC-MS analyses, the seasonal variation of leaf lipids is observed in five plant species in Qingjiang in Hubei Province. The CPI values （carbon preference index） of n-alkanes decrease gradually from May to November, though the carbon number distributions and the predominant carbon number in an individual species keep unchanged. The declined CPI values might be caused by the leaf fading, which is further supported by a comparison of the defoliated leaves with the fresh leaves. This observation infers the CPI values of n-alkanes in Quaternary sediments can be used as a tool to index the humification, and thus the climatic and the environmental conditions. The plants analyzed here show a remarkable difference in n-alkanes abundance, suggesting their differential contribution to the n-alkanes identified in sediments. The abundance and the compound species of the n-alkenes detected in the plant leaves change greatly with the seasons due to the influence of temperature, with the least compounds being identified in August.     

The ion chemistry of surface and ground waters in the Taklimakan Desert of Tarim Basin, western China

The physio-chemical and chemical features of water in natural conditions are controlled by the weath-ering of bedrocks,local climate,landforms and other geo-environmental parameters. In order to un-derstand the characteristics of water and the origins of the dissolved loads in the rivers and in the ground waters of the Taklimakan Desert,western China,we studied the ions in the water samples col-lected from rivers and wells. We collected water samples from four rivers (Keriya River,Cele River,Tumiya River and Yulongkashi River) in the southern desert and ground water samples from many parts of the desert. Major cations and anions were measured using ion-chromatograph and titration with HCl. The total dissolved solids (TDS),pH and conductivity were examined on site by a portable multi-parameter analyzer. The data show that the water in the rivers of southern Taklimakan is still of fresh water quality and slight alkalinity,although the TDS is comparatively higher than that of many other rivers of the world. The ground water is fresh to slightly saline,with TDS a little higher than that of river water in the study area. The concentration of ions is slightly different between the four rivers in the southern Taklimakan. However,the chemistries of ground water in all samples are to a large degree controlled by sodium and chloride. The ions in the ground water are concluded to be mainly from dissolving of evaporites,consistent with the dry climate in the region,whereas the ions in the rivers are mainly from rock weathering. Low-level human imprints are recognized in the ground water samples also.     

Backtracking Routing Mechanism for Improving Link Failure Recovery

Failure-insensitive routing is a good mechanism to avoid packet dropping and disconnection of forwarding when some links fail,but multiple failure links may bring routing loop for the mechanism. Backtracking routing algorithm based on inverse shortest path tree rooted at destination is presented. The feasible restoration routing is obtained through searching from the start of the failure link and tracing back to the leaves of the shortest path tree with the destination as the root. The packets are forwarded from the mounted point with smaller sequence to the mount point with bigger sequence to decrease the possible of loop in case of multi-failures. The simulations and analysis indicate that backtracking routing algorithm improves the network survivability especially for large network,at the cost of the computation complexity in the same order as failure insensitive routing.     

Nonequilibrium Thermodynamic and Dissipative Structure Mechanism of Fluidized Beds

Fluidized beds are nonlinear dynamic systems that exchange mass and energy with outside. They are governed not only by fluid dynamics, but by thermodynamics, especially the second law of thermodynamics as well. According to Prigogine's dissipative structure theory, the following have been concluded: (1) a fixed bed is on thermodynamic blanch, and bubbling, turbulent and fast beds are on the dissipatve structure branches. (2) Entropy in fluidized beds is divided into two parts: entropy production and entropy flux. The latter increases with gas velocity and decreases with pressure of the systems. That means the entropy of a system may reduce and the system with higher gas velocity behaves as dissipative structure characteristics. (3) For a given velocity, a fluidized bed operates stably on the whole, but it is unstable to local gas-solid phases. The unstable phases are described by fluid dynamic equations, While the minimum of system energy function assures whole stability of the system. (4) A transition criterion of a bubbling bed is derived from Prigogine's stability theory.     

Change of precipitation intensity spectra at different spatial scales under warming conditions

The long-term change of the whole spectra of precipitation intensity in China is examined using observed daily data recorded at 477 surface stations for the period from 1961 to 2008. The results show a spatially coherent decrease of trace precipitation despite different reduction magnitudes among the regions. For measurable precipitation, significant regional and seasonal characteristics are observed. In autumn, the whole measurable precipitation decreased over Eastern China (east of 98°E). In summer and winter, a significant increase of heavy precipitation and decrease of light precipitation are detected south of Eastern China. In Western China, measurable precipitation is found to have increased in all four seasons. Composite analysis reveals a quasi-linear relationship between increasing surface temperature and precipitation on a global scale. The responses of precipitation at different intensities to the increased temperature are distinct, with a significant spectra-shifting from light to heavy precipitation. Compared with precipitation over the ocean, the amplification of heavy precipitation over land is relatively less, most likely constrained by the limited water supply. The response of regional precipitation to global warming shows greater uncertainties compared with those on the global scale, perhaps due to interference by more complex topography and land cover, as well as human activities, among other factors.     

Noeggerathiales as coal-forming plants in Cathaysia: conclusions from an Early Permian vegetational Pompeii in Inner Mongolia

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.     

Discovery of a petrified noeggerathialean strobilus,Discinites sinensis sp.nov.from the Permian of Shizuishan,Ningxia,China

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.     

Discovery of a petrified noeggerathialean strobilus,Discinites sinensis sp. nov. from the Permian of Shizuishan, Ningxia, China

A petrified strobilusDiscinites 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 theDeltoidospora type. The new species supports the systematic placement ofDiscinites within Noeggerathiales, and the progymnosperm affinity of the Noeggerathiales.     

桂植捕线菌七号抗病及促进寄主植物生长机理的探讨

用青枯病原（Ｐｓｅｎｄｏｍｏｎａｓ　ｓｏｌａｎａｃｅａｕｍ）、西瓜萎蔫病原（Ｐｕｓａｒｉｕｍ　ｎｉｖｅｕｍ）和软腐病原（Ｅｒｗｉｎｅ　ｓｐ．）作为指示病原物菌种，接种于葡萄糖－脉－酵母粉培养基．接种点与桂植捕线菌（ＣＮ．７）的距离分别为１．６、４．２，２．３、４．５，１．８、５．０ｃｍ。结果表明，ＣＮ．７有抑制病原物菌生长的作用，距离越近．效果越明显，ＣＮ．７代射产物中可能含有抗生素。为了解ＣＮ．７与土壤肥分、同工酶的关系，设置３个处理：（１）ＣＮ．７与等体积的有机肥混合，沤制２５ｄ；（２）ＣＮ．７与等体积的有机肥混合，不沤制；（３）ＣＮ．７培养基（无菌种）与等体积的有机肥混合，不沤制（对照），用烟草进行盆栽试验，结果表明，３个处理对土壤肥分的利用率和土壤肥分的可吸收态的变化的影响均无规律可寻，表明ＣＮ．７施用后，既不能提高寄主植物对肥分的吸收率，也不能促进肥分不可利用态变成水溶态。叶片同工酶活性分析结果表明，处理（１）可提高寄主体细胞中酯酶同工酶、过氧化物同工酶的活性和酶谱带数；不同处理，过氧化氢酶同工酶和淀粉酶同工酶的活住或酶谱带数均明显变化。     

马尾松雌雄球花的形成与赤霉素和脱落酸及细胞分裂素的关系

与其邻近的枝梢顶端相比,雌球花的赤霉素ＧＡ１＋３和ＧＡ４＋７的含量显著较高,而脱落酸含量并无明显差异;雄球花与其邻近的枝梢顶端相比,则ＡＢＡ含量显著较高,而两者的ＧＡ１＋３或ＧＡ４＋７含量差异不显著;不令是雌球花或雄球花,其细胞分裂素类中的一组,玉米素核苷组的含量均显著低于其邻近的枝梢顶端,而异戊烯腺嘌呤组或二氧玉米素核苷组的含量则未见显著差异。     

北碚榕试管苗优质苗木的培育

以北碚榕试管苗为材料,炼苗后采用可降解的无纺布育苗袋育苗,研究不同育苗基质(品氏营养土、蛭石、珍珠岩、林下腐殖土的不同体积混合物)、不同叶面追肥(0.5%～2%尿素、NPK复合肥和Hoagland营养液)对苗木生长和移栽成活率的影响.结果表明,最佳育苗基质为品氏营养土,试管苗移栽30d后株高增加1.90cm,叶片增加2.75枚,移栽成活率为96.29%;最适叶面追肥为1%尿素,喷施30d后(1次/3d),株高增加1.94cm,叶片增加3.2枚,移栽成活率达100%;株高7～9cm(叶龄5～8枚)的苗木,移栽田间30d后,株高增加1.4cm,叶片增加3.4枚,移栽存活率达96.25%,长势良好.     

Jurastrobus chenii gen. et sp. nov., a cycadalean pollen cone connected with vegetative parts from Inner Mongolia, China

Cycads used to be a dominant plant group during the Mesozoic. Many fossils of cycads or their allies have been documented, but most of them are foliages. Reproductive organs are scarce and mostly found detached from vegetative organs. Among cycad reproductive parts, ovulate cones are rather frequently seen in the fossil record, while pollen cones are rare. Here we report a cycadalean pollen cone connected with its vegetative parts from the lower Jurassic of Inner Mongolia, China. The pollen cone is situated on the apex of the stem and in the center of the leaf tuft. The pinnate leaves have lateral pinnae attached decurrently and almost perpendicularly to the rachis. The characters demonstrate a strong affinity to the extant cycads. This is the first record of cycadalean pollen cone with in situ pollen grain and organically connected with its vegetative parts, and therefore sheds new light on the morphological evolution of cycad plants.     

Jurastrobus chenii gen. et sp. nov., a cycadalean pollen cone connected with vegetative parts from Inner Mongolia, China

Cycads used to be a dominant plant group during the Mesozoic. Many fossils of cycads or their allies have been documented, but most of them are foliages. Reproductive organs are scarce and mostly found detached from vegetative organs. Among cycad reproductive parts, ovulate cones are rather frequently seen in the fossil record, while pollen cones are rare. Here we report a cycadalean pollen cone connected with its vegetative parts from the lower Jurassic of Inner Mongolia, China. The pollen cone is situated on the apex of the stem and in the center of the leaf tuft. The pinnate leaves have lateral pinnae attached decurrently and almost perpendicularly to the rachis. The characters demonstrate a strong affinity to the extant cycads. This is the first record of cycadalean pollen cone with in situ pollen grain and organically connected with its vegetative parts, and therefore sheds new light on the morphological evolution of cycad plants.     

濒危植物南方红豆杉的叶面积测定及其相关分析

采用方格法和数字图像处理方法测定了濒危植物南方红豆杉[Taxus chinensis var.mairei(Lemèe&Lèvi.)Cheng et L.K.Fu]的叶面积,并对其叶片的特征指数、叶形指数、比叶面积、叶面积指数进行了相关分析.结果表明,方格法和数字图像处理方法所测得的叶面积差异不显著(P>0.05);不同方位叶片的平均叶形指数和幼叶(7.11)高于老叶(5.65),雌株(7.22)高于雄株(7.00);在同一植株中,平均叶形指数上层最大(雌7.30、雄7.58),下层(雌7.06、雄6.59)次之,中层(雌7.29、雄6.85)最小.平均比叶面积雌株(上层1 850.5,中层1 980.5,下层2336.8)高于雄株(上层1 161.5,中层1 407.8,下层1 865.3);在同一植株中,下层的比叶面积高于上层.上、下层平均叶面积指数雄株(上层0.733 8,下层0.750 1)略高于雌株(上层0.733 4,下层0.740 6);在同一植株中,叶面积指数下层高于上层,北面(雌0.758 5、雄0.758 2)高于南面(雌0.730 4、雄0.725 8).