Eocene angiosperm flowers

Collections of well-preserved angiosperm flowers from the Middle Eocene of southeastern North America include a variety of morphological types. The first of these specimens to be studied extensively, a catkin, has yielded a great deal of structural information. Floral morphology, pollen morphology, and the nature of the peltate scales suggest that this catkin is allied with extant genera of the Juglandaceae. This confirms the antiquity of some of the diagnostic floral and pollen features found in extant genera of the Juglandaceae and the importance of structural information available from fossil angiosperm flowers.     

湖南被子植物分布新记录

2013––2014年在湖南南岳衡山发现了浙江乳突果(Adelostemma microcentrum Tsiang)、小叶冷水花(Pilea microphylla(L.)Liebm.)、南方兔儿伞(Syneilesis australis Ling)、白花鬼针草(Bidens pilosa L.var.radiata Sch.–Bip.)、密苞叶薹草(Carex phyllocephala T.Koyama)和中国石蒜(Lycoris chinensis Traub)等共6个湖南省被子植物新记录种(其中5个种,1个变种,隶属5个科,6个属,乳突果属Adelostemma为湖南省新记录属),并拍摄了其植物照片,采集了其植物标本,凭证标本均存放于湖南省南岳树木园标本室。     

Unique type of angiosperm pollen from the family annonaceae

The primitive antgiosperm family Annonaceae possesses a remarkable type of pollen that appears unique in its size (diameter up to 350 micrometers), lack of exine over nearly 50 percent of the grain surface at maturity, and proximalipolar aperture. This unique pollent is further distinguished by being in polyads which are compartmentalized individually within septate stamens.     

福建被子植物分布新记录

在福建省本土野生植物调查过程中,发现3种被子植物,通过标本采集、鉴定以及查阅相关文献,分别为纤细半蒴苣苔(Hemiboea gracilis Franch.)、秋葡萄(Vitis romanetii Romanet du Caillaud)、南昆杜鹃(Rhododendron naamkwanense Merr.),均为福建省新记录种.凭证标本现存于福建农林大学标本馆.     

甘肃省被子植物4个分布新记录属

【目的】进一步明确甘肃省野生植物种类及资源分布现状,为甘肃省野生植物保护提供参考依据.【方法】在甘肃省文县境内通过实地踏查结合线路调查的方法,对该区域分布的野生植物进行标本采集并拍摄图片,通过文献检索和查阅标本馆馆藏腊叶标本的方法对其进行种类确认和分布区资料的核定.【结果】通过调查发现4个甘肃省植物新记录属,即:天葵属(Semiaquilegia)、黄肉楠属(Actinodaphne)、刺蒴麻属(Triumfetta),木犀属(Osmanthus)以及4个甘肃省植物新记录种,即:天葵[Semiaquilegia adoxoides(DC.)Makino]、红果黄肉楠[Actinodaphne cupularis(Hemsl.)Gamble]、单毛刺蒴麻(Triumfetta annua Linn.)、野桂花[Osmanthus yunnanensis(Franch.)P.S.Green].【结论】在甘肃省境内发现了4个植物新记录属及4个植物新记录种:天葵属、黄肉楠属、刺蒴麻属、木犀属及天葵、红果黄肉楠、单毛刺蒴麻、野桂花的自然个体和居群,为甘肃省的植物区系补充了新的资料.     

Selection on major components of angiosperm genomes

Angiosperms are a relatively recent evolutionary innovation, but their genome sizes have diversified remarkably since their origin, at a rate beyond that of most other taxa. Genome size is often correlated with plant growth and ecology, and extremely large genomes may be limited both ecologically and evolutionarily. Yet the relationship between genome size and natural selection remains poorly understood. The manifold cellular and physiological effects of large genomes may be a function of selection on the major components that contribute to genome size, such as transposable elements and gene duplication. To understand the nature of selection on these genomic components, both population-genetic and comparative approaches are needed.     

Archaefructaceae, a new basal angiosperm family

Archaefructaceae is proposed as a new basal angiosperm family of herbaceous aquatic plants. This family consists of the fossils Archaefructus liaoningensis and A. sinensis sp. nov. Complete plants from roots to fertile shoots are known. Their age is a minimum of 124.6 million years from the Yixian Formation, Liaoning, China. They are a sister clade to all angiosperms when their characters are included in a combined three-gene molecular and morphological analysis. Their reproductive axes lack petals and sepals and bear stamens in pairs below conduplicate carpels.     

Exocytosis in the adrenal medulla demonstrated by freeze-etching

Replicas of fractured chromaffin cells are indicative of a range of activities thought to characterize exocytosis, including attachment of secretory vesicles to the plasma membrane, fusion, extrusion of contents, and membrane retrieval. Exocytosis sites are abundant on stimulated cells but are infrequent when calcium is omitted from the system.     

Chaotic motion of europa and ganymede and the ganymede-callisto dichotomy

Europa and Ganymede may have undergone an episode of chaotic motion before the establishment of the current Laplace resonance involving the three inner Galilean satellites. During this episode, the orbital eccentricities of both satellites may have increased dramatically. As a result, the mechanical stresses due to tidal deformation of the satellites' icy lithospheres may have been large enough to result in extensive fracturing, and tidal heating may have melted water ice in the mantles of both satellites, triggering the geological activity that has modified their surfaces since the heavy cratering period. The tidal effects on Ganymede during this episode provide an explanation of the dichotomy between it and Callisto, which have similar bulk properties but very different geological histories.     

植物激素调控顶端分生组织发育的研究进展

植物分生组织的发育主要依赖于植物体内多功能干细胞群体,并受多种激素的共同调控,其中生长素和细胞分裂素调控通路及其相互作用是调控分生组织形成和分化的主要因素.了解植物分生组织的形态建成及信号途径相关分子机制,将加深人们对植物生长发育调控的认识,为植物资源进一步开发和利用提供理论基础.为此,综述了植物顶端分生组织的结构特征...     

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.     

河北省临城县小天池林区被子植物区系研究

采用植物区系地理学的研究方法,对河北省临城县小天池林区被子植物区系的组成和地理成分进行了研究。结果表明,临城县小天池林区有被子植物88科,301属,555种(包括14变种);含10种以上的优势科有14科,305种;表征科有7科;中国特有属有5属6种。该植物区的被子植物主要以北温带成分为主(共计有98属,221种,分别占总属数和总种数的37.69%和46.9 2%),这表明小天池被子植物区系具有明显的温带性质。     

Cavitation in liquids demonstrated by ultrashort-exposure radiography

Using a field-emission x-ray tube, giving a much shorter pulse of rays than does conventional apparatus, we have demonstrated around a water jet the presence of a toroidal cavity that could not be detected visually. One advantage of this method of demonstrating cavitation is that it may be used with fluids and vessels that are opaque to light.     

被子植物胚乳培养研究及其影响因素

研究报道表明,在被子植物胚乳培养过程中,供体植株的基因型、胚乳的发生类型和发育程度、胚因子、基本培养基类型、植物激素种类及用量、碳源、附加成分及低温条件都会影响不同植物的胚乳愈伤组织诱导率、分化率及胚状体诱导率和植株诱导率,其中供体植株的基因型是胚乳培养的关键因素。由于植物胚乳植株的诱导率较低,植物胚乳培养对基因型依赖较强,难以育出性状优良的三倍体植株,从而限制了胚乳植株在植物育种及遗传研究中的进一步应用。今后,应加大对植物胚乳培养的研究力度,根据利用目的,选择具有代表性的品种、品系,综合运用各种手段,提高胚乳植株诱导率,培育高抗优质的胚乳植株新品种。     

Winteraceous pollen in the lower cretaceous of Israel: early evidence of a magnolialean angiosperm family

Pollen of the primitive angiosperm family Winteraceae has been discovered in the Aptian-Albian of Israel, extending the fossil record of this phylogenetically important family of flowering plants from the uppermost Upper Cretaceous back some 40 million years to the upper Lower Cretaceous. This appears to represent the earliest known record of a magnolialean angiosperm family and is convincing evidence for the existence in the Early Cretaceous of an extant family of angiosperms.     

福建南靖3种省级被子植物新记录

[目的]福建南靖水热条件丰富,对其开展植物资源本底调查有利于厘清其植物资源本底特征,为其植物保护与利用提供基础性资料。[方法]根据全国第4次中草药资源调查规范,结合南靖县植物资源分布状况设定了42条样线,开展植物资源调查。[结果]在南靖普查期间,发现3种福建省新记录植物,分别为扇叶薹草(Carex peliosanthifolia)、光叶丰花草(Spermacoce remota)和杯苋(Cyathula prostrata),其中杯苋属为福建省新记录属。凭证标本保存于福建农林大学林学院植物标本馆(FJFC)。[结论]3种新记录植物的发现丰富了福建省本土植物基础资料。     

大蒜鳞芽生长点离体培养诱导小鳞茎的形成

用大蒜鳞芽生长点进行离体培养，结果表明，生长素ＮＡＡ浓度在０．１～１．０ｍｇ／１之间，细胞分裂素６—ＢＡ浓度在０～０．５ｍｇ／１范围内，其浓度愈低愈能促进小鳞茎的形成；贮期温度愈低，愈有利于小鳞茎的形成；３～８℃低温期大于６０天，才能保证小鳞茎的形成。