14 resultados para Fern Cave

em University of Queensland eSpace - Australia


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The biology and phenology of the eriophyid mite, Floracarus perrepae Knihinicki and Boczek,a potential biological control agent of Lygodium microphyllum (Cav.) R. Br., was studied in its native range - Queensland, Australia. F. perrepae forms leaf roll galls oil tile subpinnae of L. microphyllum. It has a simple biology, with females and males produced throughout the year. Tile Population was female biased at 10.5 to 1. The immature development time was 8.9 ± 0.1 and 7.0 ± 0.1 days; adult longevity was 30.6 ± 1.6 and 19.4 ± 1.2 days and mean fecundity per female was 54.5 ± 3.2 and 38.5 ± 1.6 eggs at 21 and 26 ° C, all respectively. Field studies showed that tile mite was active year round, with populations peaking when temperatures were cool and soil moisture levels were highest. Two species of predatory mites, Tarsonemus sp. and a species of Tydeidae, along with the pathogen Hirsutella thompsonii, had significant effects oil all life stages of F. perrepae. Despite high levels of predators and the pathogen, F. perrepae caused consistent damage to L. microphyllum at all the field sites over the entire 2 years of the study.

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The ultrastructure of the mite Floracarus perrepae was investigated in relation to its host, Lygodium microphyllum, the Old World climbing fern. Floracarus perrepae has been suggested as a means of biological control for the fern, which is an aggressive weed in tropical areas. Feeding by the mite induces a change in the size of epidermal cells, and cell division is stimulated by mite feeding, causing the leaf margin to curl over into a roll with two to three windings. The enlarged epidermal layer greatly increases its cytoplasmic contents, which become a nutritive tissue for the mite and its progeny. Damage by the mite ultimately debilitates the fern. The structure and depth of stylet penetration by the mite, and the thickness of the epidermal cell wall of L. microphyllum, do not appear to account for the mite's differential ability to induce leaf rolling in its co-adapted host from south-east Queensland but not in the invasive genotype of the fern in Florida. F

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Silicified fragments of false-trunks of the fern, Tempskya judithae sp. nov., are described from lower Cretaceous (latest Albian) sediments near Winton, central-western Queensland. The species is characterised by a three-layered sclerenchymatous cortex and a two-layered pith of sclerenchyma cells. In possessing these characters, T judithae is more similar to T readii than to other species of Tempskya. However, the Australian species differs from T readii in the abaxial shape of the petiole xylem trace (concave in T judithae, convex in T readii) and in symmetry attributes of the leaf-bases within the false-trunk (random in T judithae and radially symmetrical in T readii). T judithae is the first record of Tempskya from Australia and the second from Gondwana; the known distribution range of the genus embraces a broad area in mid-high latitudinal regions of Laurasia and the Gondwana record now comprises Australia and Argentina. Ecological signals of plant fossil assemblages recorded from the Australian sediments are in accord with flood plain habitats and a temperate climatic regime. (c) 2004 Elsevier B.V. All rights reserved.

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Biochemical properties of a polyamine oxidase (PAO; EC 1.5.3.3) purified from the aquatic nitrogen-fixing fern Azolla imbricata (Roxb.) Nak. were studied. The native molecular mass of the enzyme estimated by Sephadex G 200 get filtration was 66.2 kDa. SDS-PAGE gave a single protein band corresponding to a molecular mass of 65.5 kDa. The light yellow enzyme had absorption maxima at 278, 372 and 454 nm with 1 mol FAD per mole enzyme molecule as its cofactor. The PAO was active on both the triamine Spd and the tetraamine Spm as substrates. However, it was inactive on the diamines Put and Cad. It had a pH optimum of 6.5 for both Spd and Spm. The K-m(S) for Spd and Spm were 6.71 x 10(-2) and 1.13 x 10(-1) nM, respectively. Pre-incubation with 10 mM of K+ (KCl), Ca2(+) (CaCl2) or Mg2+ (MgCl2) had no effect on PAO activity. However, 10 mM Cu2+ (CuCl2), Mn2+ (MnCl2) and Fe2+ (FeSO4) inhibited enzyme activity by 37%, 43% and 58%, respectively. The metal chelator EDTA (10 mM), the carbonyl reagent hydroxylamine (0.5 mM) and the sulfhydryl reagent p-chloro-mercuribenzoate (0.5 mM) had no effect on PAO activity. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

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A fossil deposit excavated from the floor of Kids Cave, West Coast, South Island, New Zealand, is interpreted as having been primarily accumulated by New Zealand falcon Falco novaeseelandiae, with some contribution by Haast's eagle Harpagornis moorei. The fauna is rich: 3699 bones represented 41 bird species, two frog species, unspecified geckoes and skinks, and one bat species. Fossil deposition was mainly within the Last Glacial Maximum from about 22,000 cal yr bp to about 15,000 cal yr bp, with a marked change in sediment characteristics at the onset of the LGM's coldest period. Chronological control is given by three Uranium-series dates for a speleothem and radiocarbon AMS dating of four avian eggshell samples and one bone. The fauna is the first extensive predator accumulation of LGM age described from the West Coast of the South Island, and it indicates a palaeoenvironment of a mosaic of shrublands with forest patches. The onset of the coldest part of the LGM (Aurora 3 glacial advance, 19,500 - 19,000 cal yrs bp) saw marked climate cooling/drying affecting the site, but the avifauna indicates that although open-country taxa became more common in this period, some forest persisted nearby throughout the remainder of the LGM.

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