THE DISTRIBUTION OF SELECTED DIAGNOSTIC CHARACTERS IN THE LECANORALES

Traditional classification concepts in lichenology are often, but not always, supported by molecular results. Molecular data should be compared and correlated with micro-morphological and ultrastructural information before systematic rearrangements are undertaken. Visualization of the distribution of morphological and other characters in specified groups is considered as a desirable resultper se, but it is also important to discover whether correlating characters are dependent on each other or not; and if not, whether their distribution in a group might support existing classification concepts. A data set for lecanoralean and other lichenized and lichenicolous genera, comprising 90—mostly multi-state—characters was used to store morphological, chemical and ecological data, and to test character correlations. Several examples of such analyses are presented. The following pairs of characters show some degree of dependence: ascospore septation and number per ascus, ascospore wall type and pigmentation, ascospore and epihymenium pigmentation. Several authors postulated that ascus types are good phylogenetic markers. Ascus types have been widely used for classification concepts of the Lecanorales. Two-dimensional correlation queries of ascus types with the following morphologcal characters were made: substratum preference, thallus growth form and ascospore septation. These correlations supply characteristic profiles for the various ascus types, which have to be compared with forthcoming phylogenetic hypotheses based on molecular data.     

干旱区不同草地土壤植物系统水盐的特征

 土壤水盐状况对干旱区草地植物群落的种类组成有直接的影响。本文通过3年对土壤水盐动态(1m土壤含盐量、潜水埋深和矿化度)的定位定点监测,系统地划分出水盐等级指标,并结合草地调查,阐述了不同草地类型与水盐状况的关系,将新疆呼图壁草地生态试验站天然草地划分为沼泽化低地草甸、盐化低地草甸、重盐化低地草甸、盐土荒漠和重盐土荒漠五个亚类。     

THE EVOLUTION OF DEVELOPMENT IN DROSOPHILA MELANOGASTER SELECTED FOR POSTPONED SENESCENCE

The role of development in the evolution of postponed senescence is poorly understood despite the existence of a major gerontological theory connecting developmental rate to aging. We investigate the role of developmental rate in the laboratory evolution of aging using 24 distinct populations of Drosophila melanogaster. We have found a significant difference between the larval developmental rates of our Drosophila stocks selected for early (B) and late-life (O) fertility. This larval developmental time difference of approximately 12% (O > B) has been stable for at least 5 yr, occurs under a wide variety of rearing conditions, responds to reverse selection, and is shown for two other O-like selection treatments. Emerging adults from lines with different larval developmental rates show no significant differences in weight at emergence, thorax length, or starvation resistance. Long-developing lines (O, CO, and CB) have greater survivorship from egg to pupa and from pupa to adult, with and without strong larval competition. Crosses between slower developing populations, and a variety of other lines of evidence, indicate that neither mutation accumulation nor inbreeding depression are responsible for the extended development of our late-reproduced selection treatments. These results stand in striking contrast to other recent studies. We argue that inbreeding depression and inadvertent direct selection in other laboratories' culture regimes explain their results. We demonstrate antagonistic pleiotropy between developmental rate and preadult viability. The absence of any correlation between longevity and developmental time in our stocks refutes the developmental theory of aging.     

从河流埋藏环境看丁村遗址群的文化性质——与张森水先生商榷

丁村遗址是我国旧石器时代中期文化的重要代表。晚近有一种观点将丁村54:100和54:102地点的石制品组合从丁村文化范畴中分离出来,归入以周口店第1地点为代表的“中国北方旧石器时代工业”中,而将该遗址的其它地点划归“丁村文化B组工业。”本文认为丁村文化是一个不可分割的整体,而且丁村遗址是一个经过河流搬运埋藏的遗址群,各地点之间石制品大小和类型等特点的差异主要是由河流搬运埋藏的特点所造成的,并不是两种“工业”或两种文化传统的差异。     

菊花组织培养过程的光质效应初探

光质在菊花组织培养过程中具显著的生物学效应。试验中,绿色光可促进试管菊的生长,绿色、红色、兰色光还能部分解除~(60)Co—γ射线照射试管苗后所产生的抑制生长作用,红色光有利于花瓣愈伤组织的形成。菊花组织培养过程中的光质效应,尚与品种有关,表明品种间存在光质敏感性的差异。     

QUALITY OF THE TRIASSIC–JURASSIC BIVALVE FOSSIL RECORD IN NORTHWEST EUROPE

Abstract: The quality of the Triassic–Jurassic bivalve fossil record in northwest Europe has been measured using the Simple Completeness Metric (SCM). The SCM has been applied to the fossil record of total bivalve diversity and to the records of different ecological guilds. The Westbury and Lilstock Formations record high SCM values for most ecological groups. The ‘Pre‐Planorbis Beds’ of the lower Lias Group, however, witness a precipitous decline in the completeness of most guilds and emigration of taxa due to localized marine anoxia is a likely cause. Neither variation in lithofacies, shell mineralogy, sedimentary rock outcrop area, nor sequence architecture can convincingly explain the observed patterns of completeness. Our SCM data reveal that the Early Jurassic fossil record of infaunal suspension‐feeding bivalves is significantly poorer than that of epifaunal bivalves. Any differences in the apparent Rhaetian extinction rates between these two guilds should therefore be viewed with caution. Analyses of selectivity during the Late Triassic mass extinction based on studies of global databases appear robust in light of our SCM data. Nevertheless, future investigations of the Triassic–Jurassic benthic marine ecosystem undertaken at a finer‐resolution, may need to account for the poor quality of the Early Jurassic fossil records of certain ecological guilds, such as the infaunal suspension‐feeding taxa.