Early cretaceous angiosperm leaves from southern South america

Early angiosperm leaves from the Aptian (113 to 119 million years ago) Baqueró Formation of Patagonia have been found in a fossil flora dominated by more than 100 species of gymnosperms and pteridophytes. They may be the first early Cretaceous angiosperm leaves to be reported from southern South America and one of the few reported in the Southern Hemisphere. The leaves are large, lobate, craspedodromous, and dentate (A-1 teeth) and have ramified tertiary veins and random fourth-order venation. Several of these features have been found in coeval and younger strata elsewhere, but not in the same combination. They were probably a marginal component of the flora.     

An aptian plant with attached leaves and flowers: implications for angiosperm origin

Recent phylogenetic studies and fossil finds support a new view of the ancestral angiosperm. A diminutive fossil angiosperm from the Aptian of Australia has attached leaves, with intermediate pinnate-palmate, low-rank venation, and lateral axes bearing pistillate organs subtended by bracts and bracteoles that are the oldest direct evidence of flowers. A variety of data suggests a similar morphology for the ancestral angiosperm. This hypothesis explains similarities between rhizomatous to herbaceous Magnoliidae and basal monocots, scarcity of early agniosperm wood, and lack of recognition of earlier remains.     

广东桑园害螨发生与控制的研究

广东桑园害螨发现5种,侧多食跗线螨、菜叶螨是桑园的主要害螨。本文首次报导了受侧多食跗线螨为害后,桑叶的含水量、蛋白质、氨基酸总量的变化。 从采收方式及化学防治研究了桑园两种害螨的控制,打顶和正常采叶对两种害螨田间种群密度有不同的影响。以虫口减退率及种群趋势指数(Ⅰ)值,评价几种农药对侧多食跗线螨的控制作用,结果表明,石硫合剂和克螨特对家蚕低毒而对害螨控制效果良好,可以在桑园中使用。     

Eocene Patagonia fossils of the daisy family

Fossil capitula and pollen grains of Asteraceae from the Eocene of Patagonia, southern Argentina, exhibit morphological features recognized today in taxa, such as Mutisioideae and Carduoideae, that are phylogenetically close to the root of the asteracean tree. This fossil supports the hypothesis of a South American origin of Asteraceae and an Eocene age of divergence and suggests that an ancestral stock of Asteraceae may have formed part of a geoflora developed in southern Gondwana before the establishment of effective dispersal barriers within this landmass.     

玉米叶螨空间格局及其二阶抽样技术研究

玉米田叶螨空间格局,在较低螨口密度时呈聚集分布,在较高密度时呈均匀分布。玉米植株叶层之间,分布叶螨数量差异显著,在不同田块之间,差异不显著,玉米发育到１５～１６叶片时,第１～１０叶层上分布叶螨量占总螨量的９５．１％．应用Ｉｗａｏ根据Ｍ＊－ｍ关系提出的两阶抽样模型估计,在给定Ｄ＝０．１０,０．１５,０．２０精确水平时,每株查第１～１０叶层螨量,需要抽查的玉米株数的平均值分别为７７,３４,１９株。当取９５％置信度时,区间估计下层：Ｐ下＝〔０．９２７８,０．９７１８〕,Ｐ下＝０．９４９８,上层：Ｐ上＝〔０．０２８２,０．０７２２〕,Ｐ上＝０．０５０２．     

花卉害螨的采集和玻片标本的制作

介绍了花卉害螨标本的采集和永久性玻片标本的制作方法。标本的采集主要采取拍打枝叶,剪取受害组织和水浮法3种方法;永久性玻片标本的制作方法包括去除体内物质、染色、脱水、封片4个步骤。     

大风子科的地理分布及其起源

本文以属为单位,将大风子科84个属划分为27个分布亚型,隶属于11个分布类型。在此基础上对本科植物的地理分布进行了分析,认为大风子科是一个典型的热带性质的且富于岛屿区系成分和与各地区联系广泛的类群;其现代分布中心在旧世界热带地区,特别是热带非洲。根据其地理分布分析,结合板块及大陆漂移学说理论,可推断大风子科起源于古南大陆,特别是热带非洲地区;其起源时间至少不迟于白垩纪末期或第三纪初期,这一点已得到了古植物学资料的证实。     

Evidence for low temperatures and biologic diversity in cretaceous high latitudes of australia

A diverse terrestial biota inhabited polar latitudes during the Cretacous, 105 to 130 Ma (million years ago), along what is now the southeast coast of Australia This biota, from rocks in the Otway and Strzelecki groups, cnsisted of more than 150 taxa of vertebrates, invertebrates, and plants. Oxygen isotope ratios in diagenetic calcite suggest that mean annual temperatures were most likely less than 5 degrees C, and rings present in the fossil araucarian-podocarp-ginko woods indicate saonality. Southeastern Austalia, thus, seems to have had a cool, seasonal, nontropical climate. Dinosaurs that have been recovered are up to five species and three genera of hypsilophodontids, all of which were endemic, and three species of theropods. The occurrence of Allosaurus sp. and labyrinthodont amphibians, which had become extinct elsewhere in the Jurassic, indicate that isolation may have allowed extended surival of these taxa in Australia. In that dinosaurs coped with high latitude for at least 65 million years [Valaginian to Albian time in Australia and Campanian to Maastrictian time (80 to 65 Ma) in Alaska] suggests that cold and darkness may not have been prime factors bringing about the extinction of dinosaurs and some other groups at the Cretaceous-Tertiary boundary, unless they were prolonged.     

竹缺爪螨种群空间格局及时序动态

采用聚集度指标法测定竹缺爪螨（Aponychus corpuzae)空间格局并分析其时序动态，结果表明：竹缺爪螨卵及卵壳在林间呈聚集分布，主要分布在3年生以上竹（受害株率为97．4143％），2年生以下竹分布株率仅占0．8571％，这说明该螨主要危害3年生以上竹，且以聚集为危害为主。卵和幼螨群体在年周期中均呈聚集分布，其聚集程度对若和成螨具跟随效应。若虫和成螨存在明显的聚集－扩散周期，10a中大多数时期呈聚集分布，少数时期呈均匀分布或Poisson分布。这与该螨生物学特性及气候、营养条件密切相关。图1表2参8     

表达葡萄糖氧化酶基因抗晚疫病马铃薯的培育

葡萄糖氧化酶催化分子氧氧化b-D葡萄糖产生葡萄糖酸和H2O2。产生H2O2和其它活性氧物质是植物对病原体侵入的防御反应。实验证明H2O2水平升高不仅可诱发细胞过敏坏死反应，而且还能激活抗病基因表达如植物抗毒素及诱导病原相关蛋白（PR）等基因的表达。通过农杆菌介导将来自黑麴霉（Aspergillus niger)的葡萄糖氧化酶基因转入2个马铃薯重要栽培品种大西洋（Atlantic)和夏普蒂（Shepody)中获得23个转基因株系，其中75％为Kan抗性植株。在23个转基因株系中有16个株系可用PCR扩增出目的基因。进一步用核酸斑点杂交选出13个杂交阳性株系。转基因植物总DNA的Southem blot分析表明，GO基因已整合到马铃薯四倍体基因组中，转基因大西洋植株中目的基因为2－4个拷贝，而夏普蒂转基因植株中为1个拷贝。将转基因植株离体叶妆种呼和浩特地区流行的Phytophthoro infestans的复合生理小种1，3，4孢子。结果表明，和未转基因对照组相比转基因植株病斑出现时间晚，病斑扩展速度慢，发病程度轻，感病叶片少。总体上表现出较明显抗病性。转基因大西洋中抗性株系多于夏普蒂。转基因马铃薯植株体内H2O2含量测定表明，转基因马铃薯植株的根系和叶片在KI－淀粉培养基上数天后变为蓝色，而未转基因对照植株的根系和叶片变化不明显。试验表明，转基因马铃薯植株对晚疫病的抗性和体风H2O2含量水平呈正相关。还对马铃薯转化中再生小植株诱导，转基因植株中GO基因拷贝数，对晚疫病抗性的鉴定以及表达葡萄糖氧化酶基因的转基因马铃薯产生抗性的机理等问题进行了讨论。     

梨叶锈螨的研究

梨叶锈螨Ｅｐｉｔｒｉｍｅｒｕｓｐｙｒｉ（Ｎａｌｅｐａ）是新发现的梨树严重害螨．以成螨、若螨寄生于梨叶背主脉两侧吸汁为害．产卵繁殖，卵单产、裸露，多产于叶背主脉两侧．每年９月中旬以成螨在土壤或主干树皮裂缝中越冬，翌年４月上、中旬出蛰，全年为害期约１５０ｄ，越冬期约２１０ｄ．一年中可出现两次螨口高峰：５月上、中旬为第一高峰期，８月中、下旬为次高峰期，影响该螨发生的重要环境因素是温度、降雨、食料、梨树品种和天敌，可用涂粘虫胶环、药剂、保护利用天敌等措施综合治理．５０％三环锡、７３％克螨特２０００倍液均有极好的防治效果．     

蜂螨的种类及蜜蜂主要害螨研究进展

蜂螨是一类危害严重的蜜蜂寄生虫。随着蜂螨抗药性的产生和危害的加重,现已引起各国养蜂业的高度重视。本文从4个方面综述了近年来与蜂螨相关的研究进展:①蜂螨的种类;②重要蜜蜂害螨武氏蜂盾螨(Acarapis woodi),狄氏瓦螨(Varroa destructo)和小蜂螨(Tropilaelaps spp.)的分布、生物学特性、危害和防治方法;③与蜂螨相关的蜜蜂信息素研究;④与蜂螨相关的蜜蜂病害研究;并对今后蜂螨的研究趋势和方向进行了讨论。     

Size of the great white shark (carcharodon)

The maximum length of 36.5 feet (11.1 meters) attributed to the white shark (Carcharodon carcharias) by Günther and others is a mistake. Examination of the jaws and teeth of the specimen referred to by Günther and comparison with the jaws of white sharks of known length revealed a length of about 17 feet ( approximately 5 meters). The largest white shark reliably measured was a 21-foot (6.4-meter) individual from Cuba. Bites on whale carcasses found off southern Australia suggest that white sharks as long as 25 or 26 feet (7 (1/2) or 8 meters) exist today. The size of extinct Carcharodon has also been grossly exaggerated. Based on a projection of a curve of tooth size of Recent Carcharodon carcharias, the largest fossil Carcharodon were about 43 feet ( approximately 13 meters) long.     

The magnetic memory of Titan's ionized atmosphere

After 3 years and 31 close flybys of Titan by the Cassini Orbiter, Titan was finally observed in the shocked solar wind, outside of Saturn's magnetosphere. These observations revealed that Titan's flow-induced magnetosphere was populated by "fossil" fields originating from Saturn, to which the satellite was exposed before its excursion through the magnetopause. In addition, strong magnetic shear observed at the edge of Titan's induced magnetosphere suggests that reconnection may have been involved in the replacement of the fossil fields by the interplanetary magnetic field.     

苹果园植被多样化对叶螨天敌群落自然控制作用的评价

1989—1991年在北京国营巨山农场对地面种植苜蓿的苹果园中叶螨天敌的自然控制作用进行了系统调查和笼罩试验。结果表明,植被多样化苹果园中叶螨天敌复合体具有很强的自然控制作用,与地面清耕的单植被果园相比,叶螨的峰值低1.67倍。统计分析表明,在叶螨天敌群落中以东亚小花蝽和叶螨发生量的相关最为显著。排除笼罩试验结果表明。天敌群落对叶螨的生物学效应与天敌发生作用时间的早晚、天敌发生作用时间的长短及叶螨的密度有关。叶螨天敌自然控制的生态学效应主要表现在峰值的螨量明显降低;推迟了达到常规化防指标(2头/叶雌成螨)的时间;缓和了叶螨种群数量的波动、降低了其平衡位置;随种草年限加长,幼树园树上天敌、害螨比有增高趋势。系统结构更趋完善,幼树园种草区的高峰期螨量值比对照区低46%～89%,成树园降低28%～33%。     

为害蔬菜的朱砂叶螨生物学特性研究

朱砂叶螨[Tetranychus cinnabarinus(Boisduval)]是一种多食性螨类。该螨在吉林省长春地区一年发生6－8代，在雌螨在落叶、土块缝隙、杂草根际等处越冬。文中详述了朱砂叶螨的形态特征及主要的生物学特性。     

Deep Circulation of the North Atlantic over the Last 200,000 Years: Geochemical Evidence

Variations in the cadmium/calcium ratio of North Atlantic Deep Water are recorded in the fossil shells of benthic foraminifera. The oceanic distribution of cadmium is similar to that of the nutrients, hence the cadmium/calcium ratio in shells records temporal variations in nutrient distributions. Data from a North Atlantic sediment core show that over the past 200,000 years there has been a continuous supply of nutrient-depleted waters into the deep North Atlantic. The intensity of this source relative to nutrient-enriched southern waters diminished by about a factor of 2 during severe glaciations. This evidence combined with carbon isotope data indicates that the continental carbon inventory may have been less variable than previously suggested.     

Induced resistance of cotton seedlings to mites

Mite populations grew more rapidly on new growth of cotton seedlings that had never been exposed to mites than on new growth of plants whose cotyledons had been previously exposed to them. Experiments in which a second mite introduction on the exposed plants involved a different mite species produced this same result. The substance or substances responsible for the response are transported systemically among leaves of cotton seedlings.     

杀螨药剂防治苹果红蜘蛛田间药效试验

苹果红蜘蛛(以山楂红蜘蛛为主)是山西省苹果树上为害叶片的重要害虫,为了筛选出防效好的无公害药剂,对15%哒螨灵乳油等7种农药进行了田间药剂试验。结果表明,15%哒螨灵乳油杀螨虫效果最佳,25%四螨嗪油杀孵效果最好。因此,施药应根据田间苹果红蜘蛛成螨、若螨、卵不同虫态分布比例状况,选用有效的药剂进行轮换防治。     

Spongy mesophyll remains in fossil leaf compressions

Spongy mesophyll tissue has been discovered preserved in fossil leaf compressions. The fossils occur in an outcrop at Genesee, Alberta, Canada. The fossiliferous beds belong to the Edmonton formation of Upper Cretaceous-lower Tertiary age. The mesophyll characteristic, when taken in conjunction with other characteristics, was found useful in the identification of some fossil leaves. Numerous detailed observations as well as comparisons of both living and fossil leaves show that the remains represent neither the epidermal nor the palisade tissue.