Circumscription and lectotypification of Cycas rumphii (Cycadaceae)

The misapplied nameCycas rumphii Miquel is demonstrated to be based on discordant elements, and is lectotypified by excluding the discordant elements of the protologue. Synonymy and misapplications of the name are provided.     

New species and a new record of Cycas (Cycadaceae) from Thailand

Two newCycas species from Thailand are here described.C. petraea andC. elephantipes. A noteworthy extensions of the range ofC. macrocarpa into southeastern Thailand is recorded. New taxa are illustrated, distributions of the new taxa are mapped, and a key to the species ofCycas in Thailand is provided.     

贵州苏铁根的解剖学研究

对贵州苏铁（Cycas guizhouensis K.M.Lan et R.F.Zou）的根进行了解剖学研究,结果表明：（1）据外部形态和内部结构不同,贵州苏铁的根可分为正常根、珊瑚状根和肉质根三种类型。（2）正常根与肉质根的木栓形成层起源于表皮内方第1～2层皮层薄壁细胞,珊瑚状根的木栓形成层则起源于外方皮层的第2～3层细胞,而非中柱鞘。（3）首次发现肉质根一种新的增粗方式,是由周皮内方的皮层薄壁细胞恢复分裂能力,持续或周期性产生新的皮层薄壁细胞,引起根的增粗。     

ISSR variation in the endemic and endangered plant Cycas guizhouensis (Cycadaceae)

BACKGROUND AND AIMS: Cycas guizhouensis (Cycadaceae) is a rare and endangered species endemic to the southwest of China. An investigation was undertaken into the genetic variation of wild populations. METHODS: ISSR markers were used to determine the genetic variation within and between 12 extant populations of this species. KEY RESULTS: Low genetic diversity (at population level, P = 14.21 %, H(E) = 0.0597; at species level, P = 35.90 %, H(T) = 0.1082) and a high degree of differentiation among populations (G(ST) = 0.4321) were detected. CONCLUSIONS: This genetic structure is considered to be due to the combined effects of slow biochemical evolution, genetic drift, inbreeding and limited gene flow between populations. Based on these findings, strategies are proposed for the genetic conservation and management of the species.     

海南岛苏铁属一新种

海南岛苏铁属（苏铁科）一新种,即三亚苏铁。     

Scanning electron microscopy of the seed coat in the genus Paulovunia (Scrophulariaceae)

A comparative study of the microscopic structures of external features of mature seeds of eight Paulownia species is presented. The external surface of the seed is made up of reticulate, apparently translucent cells, which laterally extend into wing-like structures. The laterally symmetrical wings are unequally extended in the micropylar and chalazal regions. The seed-coat ornamentation has a dorsiventral nature. Some special features of seed-coat morphology amongst the eight Paulownia species are discussed.     

Isolation and characterization of microsatellite loci in endangered Cycas changjiangensis (Cycadaceae)

Eight microsatellite loci were isolated from repetitive DNA enriched libraries for Cycas changjiangensis, an endangered endemic species in Hainan Island, China. The number of allele ranged from three to seven. The observed (H _O) and expected (H _E) heterozygosities ranged from 0.0000 to 0.8750 and from 0.2359 to 0.7582, respectively. These microsatellite loci will enrich our scientific understanding for C. changjiangensis conservation.     

Isolation and characterization of microsatellite markers for Cycas debaoensis Y. C. Zhong et C. J. Chen (Cycadaceae)

Cycas debaoensis is one of the critically endangered cycad species endemic to China. In this study, we described the development of six microsatellite markers from the genome of C. debaoensis using the protocol of fast isolation by AFLP of sequences containing repeats (FIASCO) and two microsatellite markers derived from the database of expressed sequence tags (dbEST). Polymorphism of each locus was assessed in 60 adult individuals of the cycad. The average allele number of the microsatellites was 2.6 per locus, ranging from two to five. The observed and expected heterozygosities varied from 0.0833 to 0.7333 and from 0.0805 to 0.7188, respectively. Despite its rarity, only one locus (Y177) deviated from Hardy-Weinberg equilibrium due to the excessive homozygosity. The marker transferability of the eight primer pairs was tested on other four congeneric species that also occur in China.     

Maternal inheritance of plastids and mitochondria in Cycas L. (Cycadaceae)

Cycas is often considered a living fossil, thereby providing a unique model for revealing the evolution of spermatophytes. To date, the genetic inheritance of these archaic plants is not fully understood. The present study seeks to document the process of organelle inheritance in an interspecific cross of Cycas species. Extranuclear organelle DNA from chloroplasts and mitochondria was analyzed using both polymerase chain reaction-restriction fragment length polymorphism analysis and microscopy. Here, we show that the chloroplasts and mitochondria in the progeny of interspecific crosses between Cycas taitungensis and Cycas ferruginea were exclusively inherited from the female parent. Epifluorescence microscopic analyses of the pollen cells from Cycas elongata indicated that there was a significant degradation of organelle DNA in male reproductive cells following maturation; the DNA fluorescent signals were only seen after pollen mitosis two, but not detectable at mature stage. Lack of organelle DNA fluorescent signal in prothallial cells was confirmed by the absence of plastids and mitochondria in electronic microscopic images. In conclusion, these data suggest that the maternal plastid and mitochondrial inheritance in Cycas, native to the old world, are the same as seen in seed plants.     

The internal cuticle of Cirsium horridulum (Asteraceae) leaves

Leaf internal cuticle has not previously been studied in detail, and yet its existence has profound implications for the path of water movement. The internal cuticle forms a uniform layer on the inner periclinal epidermal walls that border substomatal cavities. This cuticle is continuous with the external cuticle through the stomatal pores. The thickness of the internal cuticle on nonstomatal epidermal cells is approximately one-third that of the external cuticle on the same cells. On both the abaxial and adaxial sides of the leaf the internal cuticle forms irregularly shaped islands bordered by mesophyll cells. The size of the islands coincides with the epidermal area of the substomatal cavity. The internal cuticle remains intact and connected to the external cuticle after incubation in cellulytic enzymes. After treatment with sulfuric acid or chloroform, both cuticles remain intact. The autofluorescence of both cuticles is increased by staining with auramine O. These results indicate that large portions of the leaf epidermis are covered by both an internal and an external cuticle.     

Genetic differentiation and relationships of populations in the Cycas balansae complex (Cycadaceae) and its conservation implications

BACKGROUND AND AIMS: The Cycas balansae complex is arguably a controversial group with regard to species delineation. Some taxonomists recognize a single polymorphic species while others distinguish five narrowly defined ones. The unresolved taxonomy has the potential to bring about significant problems for species conservation. Thus, an investigation to examine the genetic diversity and differentiation in the C. balansae complex was performed to determine the relationship of populations and to test whether the morphologically defined segregations represent genetically distinct units. METHODS: Inter-simple sequence repeat (ISSR) markers were employed to assess the genetic diversity in the C. balansae complex with a sample of 158 individuals from all extant populations in China. KEY RESULTS: ISSR markers revealed low genetic diversity in all populations studied (H(E) and H(O) averaged 0.0639 and 0.0798 at the population level, respectively). Phenetic analysis showed that the C. balansae complex grouped into five clusters closely corresponding to the narrowly defined C. balansae, C. parvula, C. shiwandashanica, C. tanqingii and C. simplicipinna. CONCLUSIONS: ISSR data suggest that the C. balansae complex has evolved into five genetically distinct units. These might be derived from a relatively widespread common ancestor through multiple vicariant events including geographical isolation resulting from the collision of the Indian plate with the Eurasian plate and from Pleistocene glaciations. In conservation, attention should be paid to each genetic unit.     

Genetic Variation in the Endangered Endemic Species Cycas fairylakea (Cycadaceae) in China and Implications for Conservation

Cycas fairylakea is an endangered endemic species in China. Genetic diversity within and among four natural populations of this species in China was investigated using amplified fragments length polymorphism (AFLP). A moderate to low level of intraspecific genetic diversity was detected in this species (at population level: P = 39.57 %, H₀ = 0.244; at species level: P = 60.22%, H₀ = 0.356). The among-population component accounted for, respectively, 25.7 and 31.5% of the genetic variation, according to AMOVA and Shannon’s index, indicating most of the genetic variation was found between individuals within populations. All four populations have opposite pyramid age structure, and few coning individuals, which is still decreasing. Possibly because of habitat degradation and environmental pollution, plant diseases and insect pests in the populations were extremely serious, suggesting that the main factors threatening the survival of C. fairylakea populations were not genetic variation, but human activities and the breeding system of this species.     

Genetic diversity of symbiotic cyanobacteria in Cycas revoluta (Cycadaceae)

The diversity of cyanobacterial species within the coralloid roots of an individual and populations of Cycas revoluta was investigated based on 16S rRNA gene sequences. Sixty-six coralloid roots were collected from nine natural populations of cycads on Kyushu and the Ryukyu Islands, covering the entire distribution range of the species. Approximately 400?bp of the 5'-end of 16S rRNA genes was amplified, and each was identified by denaturing gradient gel electrophoresis. Most coralloid roots harbored only one cyanobiont, Nostoc, whereas some contained two or three, representing cyanobiont diversity within a single coralloid root isolated from a natural habitat. Genotypes of Nostoc within a natural population were occasionally highly diverged and lacked DNA sequence similarity, implying genetic divergence of Nostoc. On the other hand, Nostoc genotypes showed no phylogeographic structure across the distribution range, while host cycads exhibited distinct north-south differentiation. Cycads may exist in symbiosis with either single or multiple Nostoc strains in natural soil habitats.     

哈萨克斯坦中部（Kaydagul Formation）欧洲水松的角质层结构分析

研究了哈萨克斯坦中部上渐新统／下中新统的欧洲水松(Glyptostrobus europaeus(Brongn.)Ung．)的枝叶微彤态结构,并利用扫描电子显微镜和光学显微镜与“现存最近亲缘种”——水松(G.pensilis c.Koch)的表皮特征进行了比较。     

Scanning electron microscopy studies of erythrocytes in Huntington's disease.

Scanning electron microscopic study of unmanipulated erythrocytes from Huntington's Disease (HD) patients disclosed an increased number of stomatocytes compared to controls. This morphological alteration may reflect a membrane abnormality and supports our previous electron spin resonance results (Butterfield $\text{et al}$, Nature (1977)$\text{267}$, 453–455) which suggests that HD may have diffuse membrane involvement.     

Photorespiration studies in Cycas circinalis L. and Cycas beddomei Dyer

Photosynthetic carboxylating enzymes and the effects of light and temperature on ¹⁴CO₂ efflux in two species of gymnosperm leaves were studied. The activity of RuBP carboxylase was high and that of PEP carboxylase was very low when compared to C₄ plants. The CO₂ compensation point was high. ¹⁴CO₂ efflux was greater in light than in darkness and the ratio (L/D) increased with increase in temperature and light intensity. The inhibitors of glycolate metabolism showed decreased ¹⁴CO₂ evolution in light while dark respiration was unaffected. It is concluded that both Cycas circinalis, L. and Cycas beddomei Dyer are C₃ plants.     

Nutlets micromorphology of some <Emphasis Type="Italic">Onosoma</Emphasis> L. (Boraginaceae) species from Turkey

Morphological and micromorphological characters of the nutlets of ten Onosma species in Turkey were reported. Studied fruit surfaces show some variations. Based on the structure and patterns of epidermis cells of the nutlets, two principal types can be distinguished. In Type 1, the epidermal cells of the nutlet surface are formed in a reticulate pattern with varied sizes and shapes of the meshes. This type is the most common type in the studied species. Seven of the species observed belong to the reticulate type, i.e. O. bracteosum, O. mutabile, O. aleppicum, O. bornmuelleri, O. aucheranum, O. araraticum and O. tauricum. In Type 2, the epidermal cells of the nutlet surface are formed in an elongated type with varied sizes and shapes. Three of the observed species belong to this type, i.e. O. roussaei, O. isauricum and O. stenolobum. Significant taxonomic differences between species were determined on the surface of the nutlets.     

Scanning electron microscopy of ejaculated baboon (Papio anubis) spermatozoon.

Scanning electron microscopy has been used in order to provide the morphological study including comparative measurements of the main parts of the Baboon spermatozoon. If the dimensions of the head and the mid-piece are fairly close to the human spermatozoon, the Baboon spermatozoon is practically twice as long as the human one. In the Baboon spermatozoon, the head appears smooth with only a light ransversal furrow at the level of its posterior third, which probably marks the limit of the posterior border of the equatorial segment. The mid-piece, a conical trunk, is larger in its anterior part than at the level of its posterior extremity. The end-piece appears very short as compared with the total length of the sperm cell. The technical modalities of the preparation and the possibility of artifacts are briefly discussed.     

Clearing pigmented insect cuticle to investigate small insects' organs in situ using confocal laser-scanning microscopy (CLSM)

Various microscopic techniques allow investigating structures from submicron to millimeter range, however, this is only possible if the structures of interest are not covered by pigmented cuticle. Here, we present a protocol that combines clearing of pigmented cuticle while preserving both, hard and soft tissues. The resulting transparent cuticle allows confocal laser-scanning microscopy (CLSM), which yields high-resolution images of e.g. the brain, glands, muscles and fine cuticular structures. Using a fluorescent dye, even single labeled neurons can be visualized and resolved up to an imaging depth of 150 μm through the cleared cuticle. Hydrogen-peroxide, which was used to clear the cuticle, does not preclude immunocytochemical techniques, shown by successful labeling of serotonin-immunoreactive neurons (5HT-ir) in the ants' brain. The ‘transparent insect protocol’ presented here is especially suited for small arthropods where dissection of organs is very demanding and difficult to achieve. Furthermore, the insect organs are preserved in situ thus allowing a more precise three-dimensional reconstruction of the structures of interest compared to, e.g., dissected or sectioned tissue.     

Scanning electron microscopy of trichomes of cheilanthes (sinopteridaceae)

Brittonia - The trichomes of two problematic complexes in the genusCheilanthes were studied. In one group, the trichomes ofC. tomentosa are long, multicellular, uniseriate, and flat whereas those...