Floret specialization, seed production and gender in Artemisia vulgaris L. (Asteraceae, Anthemideae)

Flowering and fruiting behaviour of female and hermaphrodite florets is described and assessed in samples from three populations from Denmark, England and Sweden. Between 25 and 50% of the florets in capitula are female, and flowering gender varies little among plants in each population. Fruiting gender of individuals, G (femaleness), varies from 0 to 0.85, because of variation in fruit set and fruit abortion. Variation in fruiting gender was correlated with plant size parameters in two populations, but not in the third. The data suggest that post-anthesis regulation of maternal investment may be operating. Florets of A. vulgaris are either totally specialized for pollen receipt (female florets) or largely specialized for pollen donation (hermaphrodite florets), and show adaptations for avoiding interference with each other in these functions. Movement of capitula from a pendent position at flowering to an erect position at fruiting optimizes positions for dissemination of pollen and of seeds respectively.     

New land tortoises (Testudines: Testudinidae) from the Miocene of Africa

The described fossil testudinids from the Miocene of Africa are reviewed. Geochelone stromeri sp. nov . is described from Lower Pliocene (Langebaanweg) and Miocene (Namib) specimens. Kinixys erosa , an extant species, is reported from Songhor Hill. Chersina sp. is reported from Arrisdrift. Impregnochelys pachytectis gen. et sp. nov . is described from Rusinga Island, Kenya, and is unique in having the anterior shell opening orientated ventrally and in having struts on the internal surface of the neurals, but shares with Kinixys a unique epiplastron shape, a high number of axillary scutes and unique orientation of the head of the femur.     

Bony Fish Myelin: Evidence for Common Major Structural Glycoproteins in Central and Peripheral Myelin of Trout

Peripheral nervous system (PNS) myelin from the rainbow trout (Salmo gairdneri) banded at a density of 0.38 M sucrose. The main myelin proteins consisted of (1) two basic proteins, BPa and BPb (11,500 and 13,000 MW, similar to those of trout central nervous system (CNS) myelin proteins BP1 and BP2), and (2) two glycosylated components, IPb (24,400 MW) and IPc (26,200 MW). IPc comigrated with trout CNS myelin protein IP2 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas trout CNS myelin protein IP1 had a lower molecular weight (23,000). Following two-dimensional separation, however, both IPb and IPc from PNS showed two components; the more acidic component of IPc comigrated with IP2 from CNS. PNS tissue autolysis led to the formation of IPa (20,000 MW), consisting of two components in isoelectric focusing of which again the more acidic one comigrated with the CNS autolysis product IP0. Limited enzymatic digestion of isolated IP proteins from PNS and CNS led to closely similar degradation patterns, being most pronounced in the case of IP2 and IPc. Immunoblotting revealed that all IP components from trout PNS and CNS myelins reacted with antibodies to trout IP1 (CNS) and bovine P0 protein (PNS) whereas antibodies to rat PLP (CNS) were entirely unreactive. All BP components from trout PNS and CNS myelins bound to antibodies against human myelin basic protein. On the basis of these studies trout PNS and CNS myelins contain at least one common IP glycoprotein, whereas other members of the IP myelin protein family appear closely related. In the CNS myelin of trout the IP components appear to replace PLP.(ABSTRACT TRUNCATED AT 250 WORDS)     

人体急性缺氧性意识障碍

实验分为低压组(低压舱7,000米)与常压组(吸入7.6％低氧混合气),每组受试者各为12名,有7名参加了两组实验。每组各有4名平均经15分23秒发生了意识模糊或丧失(通称意识障碍)。障碍者的肺泡氧分压为29.9±0.8mmHg。障碍发生前,呈现严重无力,觉醒度降低,反应迟钝,脑波特征是高幅6波(100-300μV)占优势。障碍发生时,高幅δ波丧失节律,幅度衰减,波型不规则,额枕失同步;呼吸循环代偿功能增强程度明显高于障碍前。本工作对于预测和评价人体急性缺氧引起的意识障碍有意义。     

北京东郊作物土壤系统中重金属的迁移、分布、积累

 本文研究了北京东郊污灌区重金属在作物—土壤中的迁移、分布、积累规律,证实本区蔬菜中汞含量比粮食作物约大3—15倍,比水果约大6—200倍。麦粒、糙米中的Cu、Hg、Cd、Pb、Ni的含量与土壤含量相关性不显著。架豆中重金属含量与土壤中重金属含量的相关性,只有Zn,Pb达显著水平。白菜土有机质含量与重金属含量相关性达显著水平,而白菜的重金属含量与土壤的重金属含量相关性却不显著。说明除了土壤中重金属的总量外,有效态含量的多少,是影响本区作物吸收积累重金属的主要因素。 本区施污泥的土壤和生长的作物Cd／Zn大部小于1%、盆栽试验证明：施用本区污泥污水对水稻生长发育的影响比施污泥灌清水的影响大些,因此,施用含重金属污泥时,最好不要超过5000斤／亩。大田和室内模拟试验证明：重金属从土壤中迁移到植物,由植物带走输出的量极少,其中以带走输出的Hg、Cd,As相对较多,带走输出的Pb、Cr相对的少些。     

Critical nuclear DNA size and distribution associated with S phase initiation

Using HeLa S-3 cells synchronized by selective detachment, in this paper we report a parallel study of nuclear morphology and autoradiography grain patterns between middle G₁ and middle S phases: Our results show two distinct [³H]-thymidine labeling patterns. The first “peripheral” labeling pattern has a characteristic nuclear size distribution, in contrast to the heterogeneous and varying size distributions of Feulgen-stained nuclei, and apparently is characteristic of very early S phase. The sizes of the second labeling pattern—homogeneous or inhomogeneous grain distribution throughout the nucleus—are equal or larger than the first and vary with S phase progression. Together, the corresponding nuclear sizes of the labeled nuclei represent the larger extreme of nuclear areas, and the labeling index closely parallels the fraction of nuclei with areas larger than the minimum size of the labeled nuclei. These results suggest a characteristic nuclear size (reflecting unique intranuclear DNA distribution) as a necessary, if not sufficient, requirement for S phase initiation. Parallel experimentation with rat liver cells—synchronized in vivo by partial hepatectomy and analyzed by thin section autoradiography—confirms the existence of a peripheral labeling pattern in both the very early part and the very late part of S phase, which reconciles our data with previous results and points to the fact that both initiation and termination sites for DNA replication are near the nuclear periphery.     

Dolichodorus miradvulvus n. sp. (Nematoda: Tylenchida) with a Key to Species

Dolichodorus miradvulvus n. sp. from Anubias nana Engler in Florida is described and illustrated. The female is characterized by deep grooves in the cuticle on the ventral surface just anterior and posterior to the vulva, and by transversely elongate pouches anterior and posterior to the vulva. Both sexes have a constricted area of the stylet shaft just anterior to the knobs, and on the male the intersection of the lateral field and bursa appear sclerotized.     

Antarctic nemerteans: Heteronemertea– descriptions of new taxa, reappraisals of the systematic status of existing species and a key to the heteronemerteans recorded south of latitude 50oS

Twenty-three species representative of 15 heteronemertean genera are recorded from Antarctic and Subantarctic waters south oflatitude 50^oS. Five new genera are established and seven new species are fully described and illustrated. These are Cephalurichus antarcticus gen. et sp. nov., Dokonemertes magellanensis gen. et sp. nov., Dokonemertes macquariensis sp. nov., Micrellides multiperula gen. et sp. nov., Paramicrurinella falklandica gen. et sp. nov., Parborlasia landrumae sp. nov. and Zodionemertes chilensis gen. et sp. nov. Baseodiscus antarcticus Baylis, Antarctolineus scotti (Baylis), Lineus longifissus (Hubrecht) and Parborlasia fueguina Serna de Esteban & Moretto are redescribed and illustrated and the nature of rhynchodaeal pouches protruding into the cephalic blood lacunae of Parborlasia corrugatus (Mcintosh) is reexamined and discussed. The main anatomical characters of the remaining 11 species are recorded and it is concluded that of these only Parapolia grytvikenensis Wheeler, Cerebratulus malvini Wheeler, Chilineus glandulosa (Burger), Huilkia ushuaiensis Serna de Esteban & Moretto, Micrura pacifica Friedrich and Wiolkenia friedrichi Serna de Esteban & Moretto can at present be accepted as valid, although incompletely described, taxa. Cerebratulus larseni Wheeler, Cerebratulus validus Bürger, Lineus autrani Joubin and Lineus turqueli Joubin are so poorly and inadequately described that their taxonomic status cannot be verified, and the recorded occurrence of Lineus nigricans Burger in southern latitudes cannot be substantiated on the available evidence. Maps showing the recorded distribution of all the species are included and a key to the 18 validated species is provided.     

Parapsylla, a Gondwanan element in the psyllid fauna of southern Africa (Homoptera)

The genus Parapsylla (Homoptera: Psylloidea) is redescribed and placed in the Diaphorininae of the Family Aphalaridae. Its relationships within this subfamily are discussed. The genus Agmapsylla syn. nov. is placed into the synonymy of Parapsylla , and Pennavena syn. nov. and Eudiaphorina syn. nov. are placed into the synonymy of Diaphorina. The eight known species of Parapsylla are distributed in southern Africa and upland areas of East Africa. Host plant relationships are not clearly established but the genus appears to be associated with species of Maytenus (Celastraceae), Olinia (Oliniaceae) and possibly Olea (Oleaceae) and Syzygium (Myrtaceae). Parapsylla relicta syn. nov, and A. aureus syn. nov. are placed into the synonymy of Arytaina capensis. Parapsylla capensis comb. nov. is transferred from Arytaina, Parapsylla valens comb. nov. is transferred from Diaphorina , and the following new species are described: P. angolensis sp. nov., P. eafra sp. nov., P. huila sp. nov., P. marginipennis sp. nov., P. rufa sp. nov. and P. theroni sp. nov.     

Effects of irradiation level on leaf growth of sunflower

Sunflower, Helianthus annuus L. cv. INRA 6501, plants were grown in a gravel culture subirrigated with Hoagland nutrient solution, at photosynthetically active radiation levels of 15, 30 and 60 W m^-2 at a daylength of 16 h, a temperature of 20°C and a relative humidity of 60% throughout. Development of the plant and growth of the leaves were measured. High irradiance accelerated development proportionally in all phases from germination, through leaf initiation, primordial flower formation and the maturation of all plant organs until anthesis. High irradiance levels stimulated the expansion of the growing shoot, which produced more and larger primordia. Under constant conditions the ratio between leaf initiation rate and mature length of a leaf remained constant, although the growth patterns [relationship between relative growth rate (RGR) and organ age] of successive leaves were not similar. Consequently, it may be assumed that, as in poplar, the increasing size of the growing shoot reflects the increase of the vascular system of sunflower. The growth patterns of the leaves depend on the developmental stage of the plant and, in the young primordial stage, also on irradiance level. In the linear phase of growth the growth pattern is independent of irradiance level.