中国花楸属植物的分布及研究现状

花楸属(Sorbus L.)植物冠形多态、花色秀美、果实缤纷、四季叶色各异，具有很高的园艺观赏价值，但因属下种间杂交、多倍化和无融合生殖的存在，所以花楸属也是分类学上比较困难的一个类群。该研究通过细致整理和分析国家标本资源库和全球数字化植物标本数据库中花楸属植物标本信息，了解中国花楸属物种采集位置和野生种质资源的分布中心，构建中国花楸属植物标本数据库，为全国第一次林草种质资源的普查与收集提供参考；在明晰花楸属植物资源分布位置和生境的基础上，发现中国花楸属植物资源居世界之首且花楸属物种多分布在高海拔区域，尤其是在中国西南部的山区，分布有一半以上的中国花楸属物种，在该区域花楸属物种多种倍性并存、杂交频繁发生。然而，这是否为该属植物物种多样性丰富的关键因素，把高海拔分布的花楸属物种引种到低海拔区域能否适应以及如何适应低海拔的夏季高温尚不清楚。基于此，作者就自己的专业领域进一步检索了花楸属植物在形态分类与系统发育、适应性进化和保护遗传学、植物资源利用等方面的研究现状，梳理出花楸属植物目前研究尚未解决的问题，并进一步指出未来研究需重点关注的方向。建议未来的研究重点关注以下问题：(1)在坚实的系统...     

Development of respiratory structures in embryos and first and second instars of the bark scorpion,Centruroides gracilis (Scorpiones: Buthidae)

The SEM was used to study the development of respiratory structures in successive stages in relation to the overall changes occurring in the scorpions. Book lung development is a slow process, starting with spiracles and a sac‐like atrium in the early embryo and continuing lamellar formation to 150 or more in the adult. In the embryo, the primordial epithelial cells become aligned in a planar pattern as they secrete granules of material that aggregate spontaneously to form the cuticular walls of the lamellae. A blade‐like structure is formed consisting of cells sandwiched within the two cuticle walls they secreted. These cells are in the primordial air channel. The adjacent hemolymph channel is nearly devoid of cells, but cross‐bridges develop and help stabilize the cuticle walls and maintain the width of the channel. The cells in the primordial air channel undergo cytolysis, leaving it open for air except for cuticular cross‐bridges. Development continues in the newborn (first instars); the air channels of some lamellae still contain cells and are not yet functional for gas exchange. The first instars are weak and relatively inactive. They climb up on the mother's dorsum until the first molt (about 8 days). With the cuticular walls of the lamellae in place, cells adhering to the wall in the hemolymph channel produce a thin, new tissue layer (epithelium) on the lamellar wall facing the hemolymph channel. This layer has many discontinuities as though it is slowly developing. Formation of the tissue layer and cytolysis of the cells in the air channels continue through the first molt in which little book lung cuticle is shed as exuvium. The air channels of the second instars (foraging nymphs) are now cell free and open for air passage except for the cross‐bridges. The tissue layer is still incomplete and continues to be formed. It may provide the hypodermal primordium for cuticle replacement in later molts, but development was not studied beyond the second instar except for comparison with book lungs in the adult. The blade‐like lamellae in the adult are larger and more numerous than in the second instar, but in the anterior book lung the shape of the cuticle wall and cross‐bridges and the widths of the air and hemolymph channels are about the same as in the second instar. The air channels in the posterior part of the lamellae have distinctive, vein‐like space‐holders. The similarity of the adult anterior lamellae with those in the second instar suggests retention of this part through the 4–5 molts to maturation, and/or cell processes like those in the embryo are repeated, but this needs to be examined in further studies of cell and cuticle changes before and during the molts. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.     

Male behaviour over the season in a wild population of the field cricket Gryllus campestris L.

Abstract.  1. Cricket model systems have greatly enhanced our knowledge about mate choice and sexual selection. However, no studies exist that take seasonal dynamics into account and that follow individual males over the complete adult stage in the wild. In the present study, all adult field crickets ( Gryllus campestris L.) were individually marked and measured in a population in central Germany and their behaviour was followed over their life from May to July 2000.
2. The population reached a maximum of 108 males within 10 days and continuously declined thereafter. Daily mortality was positively correlated with burrow-changing activity, which was highest at high mean temperatures. Median burrow occupation time was short at 1 day but males stayed up to 34 days in one burrow. Heavy males stayed longer in burrows and achieved a higher age.
3.  Male displacement was on average 2.8 m per day and up to 284 m during their life. Displacement and lifespan were negatively correlated.
4. Burrows were highly aggregated at the meadow in areas of vegetation cover <85%. Aggregation of males increased with advancing season and declining population size. Consequently, nearest-neighbour distances remained stable at 5 m until the 50th day of the study.
5. About half of the 159 detected matings occurred 4–6 h after sunrise. An increased mating frequency was observed between the 30th and 50th day after adult moult.     

Appearance of ocular electrical responses during development of cavernicolous and epigaeic opilionids (Arachnida)

The appearance of the electroretinogram was established during the development of two species of opilionids, an epigaeic species, Pachylus chilensis, and a cavernicolous one, Ischyropsalis luteipes. In nymphs and adults of the two species, electroretinograms of about the same amplitude can be recorded. During embryonic and larval development they are quite different. In Ischyropsalis luteipes, it is impossible to record an electrical response before hatching. In Pachylus chilensis on the other hand an initial inconstant and very small response occurs from the 50th hour of development of the retina and can always be recorded from the 72nd hour. In older embryos, the response has a progressively greater amplitude, but remains a simple negative wave. On the tenth day, when the first synaptic relays appear, the electroretinogram takes the shape of that of the adult. Given that transmission electronic microscopy cannot detect differences between the microvilli of these two species, it is tempting to compare Ischyropsalis luteipes lack of response with that of the mutant norp A of Drosophila melanogaster in which transmission electron microscopy shows no marked difference, whereas freeze-etching shows a very low number of intramembranous particles.     

Developmental differences in visceral morphology of megophryine pelobatid tadpoles in relation to their body form and mode of life

Tadpoles face severe packing constraints on viscera within the pleuro-peritoneal cavity because of their extremely short torsos—a feature they share with adult anurans—and the concomitant need for relatively slender torsos for efficient locomotion. We examined the effects of differences in body form and habits on the size, shape and development of viscera in three kinds of sympatric, stream-associated pelobatid tadpoles. Leptobrachium montanumlarvae are generalized, wide, deep-bodied tadpoles. Larval Leptolalax gracilis are very slender and live in the crevices between rocks on the bottom of riffles. Larval Megophrys nasuta are intermediate between the other two in body form, and live with L. montanum in a variety of microhabitats but feed at the surface film. In all three species, liver, gall bladder, arid kidneys begin development early and grow isometrically throughout larval life. The gut and pancreas have a growth spurt shortly after hatching, then grow at a constant rate until near metamorphosis when both shrink drastically. The spleen grows at a slower rate than the body throughout the larval period. Lungs do not appear in L. gracilis until the tadpole approaches metamorphosis, which accords with its benthic habits, whereas they grow throughout the larval period in L. montanum and M. nasuta. In M. nasuta, however, the lungs are unusually wide anteriorly; this shifts buoyancy forward and facilitates the head-up feeding posture characteristic of that species. Gonads appear early in L. montanum and L. gracilis, but not until near metamorphosis in M. nasuta. We suggest that accelerated gonadal development in tadpoles characterizes species that metamorphose close to their size at first reproduction. Leptobrachium montanum, with the bulkiest body and most generalized habits, has relatively and absolutely the largest gut, liver (x of combined gut and liver volume = 24%, of total volume), and kidneys. Leptolalax gracilis, the most slender tadpole, has relatively the smallest combined gut and liver volume (x = 10% of total volume). Other premetamorphic differences among the species were observed in gut coiling, liver, pancreas and kidney shape and left/right asymmetry of urogenital organs. The major interspecific differences we observed in the size, shape, and developmental patterns of viscera in tadpoles are clearly related to interspecific differences in torso shape, microhabitat distribution and mode of feeding.     

Investing in early human development: Timing and economic efficiency

Policy discussions to ameliorate socioeconomic (SES) inequalities are increasingly focused on investments in early childhood. Yet such interventions are costly to implement, and clear evidence on the optimal time to intervene to yield a high economic and social return in the future is meagre. The majority of successful early childhood interventions start in the preschool years. However socioeconomic gradients in cognitive skills, socio-emotional functioning and health can be observed by age three, suggesting that preventative programmes starting earlier in childhood may be even more effective. We discuss the optimal timing of early childhood intervention with reference to recent research in developmental neuroscience. We motivate the need for early intervention by providing an overview of the impact of adverse risk factors during the antenatal and early childhood periods on outcomes later in life. We provide a brief review of the economic rationale for investing early in life and propose the “antenatal investment hypothesis”. We conclude by discussing a suite of new European interventions that will inform this optimal timing debate.     

Muscle fiber type characteristics in females with chronic obstructive pulmonary disease. A preliminary study

Chronic obstructive pulmonary disease (COPD) is known to elicit intrinsic abnormalities in male skeletal muscle. However, it is unclear to what extent these changes occur in women and whether they are fiber-type specific. We investigated fiber-type specific differences in selected histochemical properties in muscle obtained from women with moderate to severe COPD compared to healthy control (CON) women. Tissue was obtained from the vastus lateralis in five COPD patients (age 66.9 ± 2.6 years; FEV₁ = 43 ± 7%) and eight CON (age 68 ± 4.9 years; FEV₁ = 113 ± 4.2%). Compared to CON, the distribution (30.6 ± 5.2 vs. 57.9 ± 4.6%) and cross sectional area of type I (CSA, 5660 ± 329 vs. 3586 ± 257 μm²) and type IIA (2770 ± 302 vs. 2099 ± 206 μm²) were lower (P < 0.05) and higher (P < 0.05), respectively, in COPD. Disease state did not alter either the distribution or CSA of the IIA, IIAX or type X subtypes. Although differences were found between fiber types in the number of capillary contacts (n) (I > IIAX, IIX; IIA > IIX) and the capillaries per CSA (μm²10⁻³) (I < IIA, IIAX, IIX), no differences were found between CON and COPD. Succinic dehydrogenase activity and sarcoplasmic reticulum (SR) Ca²⁺-ATPase activity, measured photometrically (OD units), were higher (P < 0.05), and lower (P < 0.05), respectively, in type I compared to the type II fiber subtypes. These properties were not altered with COPD. COPD in females is accompanied by a higher percent of type II fibers, a larger CSA of type I and type IIA fibers, both of which occur in the absence of differences in oxidative potential and the potential for SR Ca²⁺-sequestration.     

Phenotyping mouse chromosome substitution strains reveal multiple QTLs for febrile seizure susceptibility

Febrile seizures (FS) are the most common seizure type in children and recurrent FS are a risk factor for developing temporal lobe epilepsy. Although the mechanisms underlying FS are largely unknown, recent family, twin and animal studies indicate that genetics are important in FS susceptibility. Here, a forward genetic strategy was used employing mouse chromosome substitution strains (CSS) to identify novel FS susceptibility quantitative trait loci (QTLs). FS were induced by exposure to warm air at postnatal day 14. Video electroencephalogram monitoring identified tonic–clonic convulsion onset, defined as febrile seizure latency (FSL), as a reliable phenotypic parameter to determine FS susceptibility. FSL was determined in both sexes of the host strain (C57BL/6J), the donor strain (A/J) and CSS. C57BL/6J mice were more susceptible to FS than A/J mice. Phenotypic screening of the CSS panel identified six strains (CSS1, -2, -6 -10, -13 and -X) carrying QTLs for FS susceptibility. CSS1, -10 and -13 were less susceptible (protective QTLs), whereas CSS2, -6 and -X were more susceptible (susceptibility QTLs) to FS than the C57BL/6J strain. Our data show that mouse FS susceptibility is determined by complex genetics, which is distinct from that for chemically induced seizures. This is the first data set using CSS to screen for a seizure trait in mouse pups. It provides evidence for common FS susceptibility QTLs that serve as starting points to fine map FS susceptibility QTLs and to identify FS susceptibility genes. This will increase our understanding of human FS, working toward the identification of new therapeutic targets.     

药用植物乌蕨配子体发育的观察

药用植物乌蕨(Stenoloma chusanum(L.)Ching)配子体发育周期短而迅速,是一种研究蕨类配子体世代的生理生态和分子生物学等特征的理想试验材料.本文采用原生境腐殖土培养方法对乌蕨的孢子进行人工培养,观察并记录其孢子萌发和配子体发育的过程.结果表明:乌蕨孢子呈黄色,单裂缝,二面体形;孢子萌发为书带蕨型(Vittaria-type).丝状体4～6个细胞,有时具二叉分枝.片状体为长楔形,达6～8个细胞宽.成熟的原叶体为对称心形,裸露,发育为槲蕨型(Drynaria-type),并且具备一定的营养繁殖能力.原叶体上的假根为单细胞且不含叶绿体.精子器为盖裂开放,颈卵器短而直立.利用孢子培养的方法对乌蕨种苗进行人工繁殖,将为保护性开发利用这一重要药用资源奠定基础.