Monocaryotization of Cultures of Lenzites trabea (Pers.) Fr. and other Wood-destroying Basidiomycetes

Cultures of Lenzites trabea and some other basidiomycetes grownon nutrient agar containing high concentrations of sodium arsenateconsistently reverted from the dicaryotic to the monocaryoticcondition. This effect could also be induced by a wide varietyof other toxicants, including copper sulphate, zinc sulphate,sodium dichromate, sodium pentachlorophenate, creosote, crystalviolet, boric acid, and sodium taurocholate, but sodium arsenatewas the most reliable monocaryotizing agent, being effectivewith eight of the fourteen basidio-mycete species tested withit. The neohaplonts formed by sodium arsenate and other toxicantsmate normally with each other and with compatible monosporeisolates. The value of chemical monocaryotization as a techniquein fungal genetics and experimental taxonomy is discussed. Byusing the mating factor alleles as genetic markers, it was demonstratedthat when L. trabea is monocaryo-tized by sodium arsenate orcopper sulphate, only one of the two nuclei in the dicaryoncan be recovered in the neohaplonts, the direction of this completenuclear selection depending on the toxicant and the dicaryonconcerned. It was shown to occur in treated wood blocks duringroutine soil-block decay tests of inorganic wood preservativesand it is probably a frequent, though hitherto unrecognized,occurrence in the laboratory testing of wood preservatives andother fungicides against basidiomycetes.     

Phosphorus benefits of different legume crops to subsequent wheat grown in different soils of Western Australia

Certain legume crops, including white lupin (Lupinus albus L.), mobilise soil-bound phosphorus (P) through root exudates. The changes in the rhizosphere enhance P availability to these crops, and possibly to subsequent crops growing in the same soil. We conducted a pot experiment to compare phosphorus acquisition of three legume species with that of wheat, and to determine whether the legume crops influence growth and P uptake of a subsequent wheat crop. Field pea (Pisum sativum L.), faba bean (Vicia faba L.), white lupin (Lupinus albus L.) and wheat (Triticum aestivum L.) were grown in three different soils to which we added no or 20 mg P kg^–1 soil (P0, P20). Growth, P content and rhizosphere carboxylates varied significantly amongst crops, soils and P levels. Total P content of the plants was increased with applied phosphorus. Phosphorus content of faba bean was 3.9 and 8.8 mg/pot, at P0 and P20, respectively, which was about double that of all other species at the respective P levels. Field pea and white lupin had large amounts of rhizosphere carboxylates, whereas wheat and faba bean had negligible amounts in all three soils at both P levels. Wheat grew better after legumes than after wheat in all three soils. The effect of the previous plant species was greater when these previous species had received P fertiliser. All the legumes increased plant biomass of subsequent wheat significantly over the unplanted pots in all the soils. Faba bean was unparalleled in promoting subsequent wheat growth on all fertilised soils. This experiment clearly demonstrated a residual benefit of the legume crops on the growth of the subsequent wheat crop due to enhanced P uptake. Faba bean appeared to be a suitable P-mobilising legume crop plant for use in rotations with wheat.     

Morphological and functional aspects of volatile-producing glands in bees (Hymenoptera: Apidae)

Abstract In this paper we focus on the occurrence and morphological aspects of exocrine glands in several bee species. Morphology of head labial, mandibular, Dufour, and abdominal tegumentar glands was investigated under light microscopy, scanning electron microscopy and transmission electron microscopy. Most of such glands present cells with cytoplasm homogeneous and acidophilic, or contain small apparently empty vacuoles. The cytoplasm cells' ultrastructure showed a well developed smooth endoplasmic reticulum, many polymorphic mitochondria, rare Golgi, lipid droplets, myelin figures, and many basal and apical plasma membrane infoldings. All these results are discussed in the text.     

On the identity of turmeric: the typification of Curcuma longa L. (Zingiberaceae)

Although Curcuma L. (Zingiberaceae) is a conserved name, with C. longa L. as its conserved type, the type of C. longa is still uncertain. Numerous discussions about the identity of the taxon called C. longa by Linnaeus have been followed by various attempts to rename turmeric, suggestions as how to settle the type and proposals to conserve the name from a later author in order to stabilize the situation. Unfortunately, none of the previous proposals can be upheld for reasons which are discussed in this article. A lectotype is selected from extant material examined by Linnaeus and an epitype collected near the type locality is designated here. The identity of C. longa is discussed and a colour plate of the species is included. Synonyms of C. longa and their types are discussed and notes on the variability of C. longa are provided.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 37–46.     

Occurrence of secretory structures in underground systems of seven Asteraceae species

In contrast with the abundance of anatomical studies of secretory structures on aerial vegetative organs of Asteraceae species, the information about secretory structures on thickened subterranean organs is sparse. The aim of this study was to investigate the occurrence of secretory structures on thickened and nonthickened subterranean organs of seven Asteraceae species from three tribes: Eupatorieae (Chromolaena squalida and Gyptis lanigera), Vernonieae (Chresta sphaerocephala, Lessingianthus bardanoides, L. glabratus and Orthopappus angustifolius), and Plucheeae (Pterocaulon angustifolium). The specimens were collected in areas of cerrado from the State of São Paulo, Brazil. All species of the tribe Vernonieae studied exhibited endodermic cells, other than the epithelial cells of the canal, with secretory activity in the roots. In C. sphaerocephala roots, two types of endodermic cell were found, but only one had secretory activity. Secretory canals were found in the tuberous and nontuberous roots of all studied species. These data agree with the results from the literature for Asteraceae species. Here, we describe for the first time in Asteraceae the presence of secretory idioblasts in C. sphaerocephala. Secretory trichomes are present in the Orthopappus angustifolius rhizophore. Histochemical tests have shown that all types of secretory structure possess substances containing lipids. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 789–796.     

我国洪涝灾害受灾及成灾面积的预测分析

运用ＳＡＳ软件的非线性回归,并结合马尔可夫链方法建立了因洪涝灾害造成的我国农田受灾及成灾面积的２个预测模型,结果表明本文所作的预测效果较好,为我国的灾害预测提供了一种方便实用的方法。     

MYGALOMORPH SPIDERS (ARANEAE: DIPLURIDAE) FROM THE LOWER CRETACEOUS CRATO LAGERSTÄTTE, ARARIPE BASIN, NORTH-EAST BRAZIL

Abstract:  The first mygalomorph spiders from the Lower Cretaceous Crato Lagerstätte of Cearà Province, north-east Brazil, are described, from adult males and females, in two new genera and species: Cretadiplura ceara Selden, gen. et sp. nov. and Dinodiplura ambulacra Selden, gen. et sp. nov. They belong to the extant family Dipluridae, hitherto known as fossils only from Tertiary strata; thus this occurrence extends the family record by some 90 myr.     

Triggers of phytoplankton bloom dynamics in permanently eutrophic waters of a South African estuary

The permanently eutrophic Sundays Estuary experiences recurrent harmful algal blooms (HABs) of Heterosigma akashiwo (Raphidophyceae). This study aimed to identify the environmental variables shaping phytoplankton community composition and succession patterns during a typical spring/summer harmful algal bloom (HAB) period. Monitoring of abiotic and phytoplankton variables was undertaken over the period of a month in 2016. Surface water salinity corresponding to mesohaline conditions (9 to 12) was a prerequisite for site selection. During the study, two HABs (>550 µg Chl a l^?1) of H. akashiwo occurred, each lasting for approximately a week in duration. Analyses highlighted nutrient depletion (i.e. nitrate and phosphate concentrations) as the key constraint on bloom duration. When the density of H. akashiwo decreased, the community composition became more diverse with species belonging to Bacillariophyceae and Dinophyceae becoming more abundant; albeit to a lesser degree (<180 µg Chl a l^?1). Dissolved oxygen shifted from super-saturated conditions (>14 mg l^?1) during peak HAB conditions, to instances of bottom water oxygen depletion (2–4 mg l^?1) during the decay phase. These findings highlight the potential severity of transforming a catchment from natural to one that is highly regulated by agricultural practices, while also emphasising the need for management intervention.