Does flooding affect spatiotemporal variation of fish assemblages in temperate floodplain wetlands?

1. Floodplain wetlands are productive components of lowland rivers and are thought to be important habitat and nurseries for many fish species. Fish assemblages inhabiting floodplain wetlands vary considerably through space and time and are largely shaped by wetting/drying cycles, although there is little understanding how many aspects of flooding (e.g. magnitude, timing, duration, frequency) influence the fish assemblages. As a consequence, decisions on flooding of wetlands by managers aimed at restoring native fish assemblages are often based on limited knowledge. 2. This study examined the importance of total duration of flooding on the temporal and spatial dynamics of wetland fish assemblages in the Murray River, in south‐eastern Australia. The study examined: (i) how the abundance of 0+ and 1+ fish varied with wetland, season and the duration of wetland filling; (ii) how environmental parameters, including food production changed in relation to the duration of wetland filling; (iii) changes in condition indices for the most abundant species and (iv) changes in species richness and total abundance over time. 3. The 0+ fish assemblage varied more through space and time than the 1+ assemblage. Longer cumulative river–wetland filling was associated with greater total abundances of newly recruited (0+) fish; this was particularly true for common carp (Cyprinus carpio, alien) and carp gudgeon (Hypseleotris spp., native). The body condition of carp gudgeon also increased with the duration of filling, even though static measures of food production declined. The small flooding events that occurred as part of this study did not translate into measurable improvements in the fish assemblage over the longer term (3 years), but did prevent wetlands from drying and thus maintained these habitats as refuges.     

Studies on organic acid metabolism and ethylene production during controlled atmosphere storage of apples {Mallus pumila MILLER, cv. Rolls)

Organic acid metabolism and ethylene formation during controlledatmosphere storage (CA-storage) of apples (Mallus pumila MILLER,cv Rolls) were studied. A higher titratable acidity was observedin apples during CA-storage as compared to those in air control.The incorporation of atmospheric ¹⁴CO₂ into malic acid was greaterin apples stored in the higher CO₂ concentration. The conversionof succinic acid-¹⁴C into fumaric acid-¹⁴C was slightly lessin the apple in modified high carbon dioxide atmosphere thanthose in air. O₂ uptake and CO₂ output by apple slices weremarkedly inhibited by the addition of succinic and malic acidsat a concentration higher than 25 mM. These factors seem to be the possible cause of a higher acidityof fruits stored in CA-condition. Ethylene production from wholefruits or tissue slices was markedly inhibited under CA-condition. The retardation of acid metabolism and the inhibition of ethyleneproduction of apples during CA-storage seem to be the importantfactors which help to maintain their storage quality. (Received March 18, 1970; )     

Studies on anaerobic biphasic growth of a denitrifying bacterium, Pseudomonas stutzeri

Growth of Pseudomonas stutzeri(VAN NIEL strain) in the presenceof a limiting amount of nitrate under anaerobic conditions ischaracterized by 2 logarithmic phases separated distinctly byan intermediate phase where the growth rate is very low. Inthe first logarithmic phase nitrate is reduced stoichiometricallyto nitrite stage, and in the second phase nitrite is reducedto nitrogen gas. The nitrite reducing activity of cells in the second growthphase is 3–4 times higher than that of cells in the firstphase. The rise in nitrite reducing activity is correlated witha remarkable increase in the content of cytochromes a₂ and c-552. ¹Present address: Department of Biochemistry, Hiroshima UniversitySchool of Dentistry, Hiroshima, Japan. ²Present address: Institute of Molecular Biology, Faculty ofScience, Nagoya University, Nagoya, Japan. (Received June 16, 1969; )     

Development of the Major Triterpenoids and Oil in the Fruit and Seeds of Neem (Azadirachta indica)

In order to learn the best time for harvesting Neem (Azadirachtaindica) seeds, the amount of the five major triterpenoids, togetherwith the oil content have been determined throughout a fruitingseason in six selected trees in Sri Lanka. The triterpenoidcontent and the relative proportions of the major compoundschanged little from the hard green fruit stage to mature seeds,while the oil content increased markedly with time. The highestcontent of azadirachtin (10 mg g^-1seed kernels) was recordedin newly ripened seeds. There was some loss of salannin andazadirachtin in storage after harvesting for up to 6 months. Azadirachtin; salannin; nimbin; neem seeds; neem fruit; seasonal change; neem oil; seed storage; Azadirachta indica ; Meliaceae     

Bud-burst modelling in Siberia and its impact on quantifying the carbon budget

Vegetation phenology is affected by climate change and in turn feeds back on climate by affecting the annual carbon uptake by vegetation. To quantify the impact of phenology on terrestrial carbon fluxes, we calibrate a bud‐burst model and embed it in the Sheffield dynamic global vegetation model (SDGVM) in order to perform carbon budget calculations. Bud‐burst dates derived from the VEGETATION sensor onboard the SPOT‐4 satellite are used to calibrate a range of bud‐burst models. This dataset has been recently developed using a new methodology based on the normalized difference water index, which is able to distinguish snowmelt from the onset of vegetation activity after winter. After calibration, a simple spring warming model was found to perform as well as more complex models accounting for a chilling requirement, and hence it was used for the carbon flux calculations. The root mean square difference (RMSD) between the calibrated model and the VEGETATION dataset was 6.5 days, and was 6.9 days between the calibrated model and independent ground observations of bud‐burst available at nine locations over Siberia. The effects of bud‐burst model uncertainties on the carbon budget were evaluated using the SDGVM. The 6.5 days RMSD in the bud‐burst date (a 6% variation in the growing season length), treated as a random noise, translates into about 41 g cm^?2 yr^?1 in net primary production (NPP), which corresponds to 8% of the mean NPP. This is a moderate impact and suggests the calibrated model is accurate enough for carbon budget calculations. In addition to random differences between the calibrated model and VEGETATION data, systematic errors between the calibrated bud‐burst model and true ground behaviour may occur, because of bias in the temperature dataset or because the bud‐burst detected by VEGETATION is because of some other phenological indicator. A systematic error of 1 day in bud‐burst translates into a 10 g cm^?2 yr^?1 error in NPP (about 2%). Based on the limited available ground data, any systematic error because of the use of VEGETATION data should not lead to significant errors in the calculated carbon flux. In contrast, widely used methods based on the normalized difference vegetation index from the advanced very high resolution radiometer satellite are likely to confuse snowmelt and vegetation greening, leading to errors of up to 15 days in bud‐burst date, with consequent large errors in carbon flux calculations.     

The phylogeny of lance lacewings (Neuroptera: Osmylidae)

The first phylogeny of the lacewing family Osmylidae is presented here based on a total evidence analysis of DNA sequences for multiple gene loci and morphology for representatives of almost all extant genera. Our phylogeny shows a basal dichotomy in the family, with subfamilies Protosmylinae, Spilosmylinae and Gumillinae comprising one lineage, and the other lineage including Osmylinae, Porisminae, Eidoporisminae, Kempyninae and Stenosmylinae. The status of Paryphosmylus Krüger and Lysmus Navás as members of Protosmylinae is affirmed as well as the placement of Gumillinae near Protosmylinae and Spilosmylinae. Our results suggest that Porisminae, Eidoporisminae and Stenosmylinae evolved from a common ancestor, and their relationships, including likely paraphyly of Stenosmylinae, requires further assessment. Divergence time analysis revealed that the family originated during the Late Permian before the break‐up of the supercontinent Pangaea and that present generic distributions are not due to Gondwanan biogeographic events. All major subfamily‐level lineages were present by the end of the Triassic, in agreement with the rich Mesozoic‐aged fossil record for the family.     

Stimulative effect of potassium ion on starch synthetase of different plant origins

The stimulative effect of K⁺ on the activity of granule-boundstarch synthetase was uniformly observed in the enzyme preparationsobtained from the root, leaf and stem of sweet potato plants.The stimulation of K⁺ was most marked with the sweet potatoenzyme, while the broad bean enzyme was also appreciably stimulated.The K⁺-effect was very small in the enzyme from rice, barleyand taro plants. (Received October 25, 1968; )     

CHEMICAL NATURE OF YEAST SEXUAL HORMONES

From culture media of yeast cells of the two mating types, a and α, hormones, which made cells of the opposite mating type expand, were extracted with methylene chloride. They were then isolated by either thin layer chromatography or vacuum distillation. The isolated hormones showed color reactions of steroidal compounds. According to Rf values and UV absorption spectra, the two yeast hormones apparently are different from testosterone and estradiol, which have activity similar to that of the yeast sexual hormones excreted by a and α type cells, respectively.     

Phylogeny,divergence times and biogeography of window flies (Scenopinidae) and the therevoid clade (Diptera: Asiloidea)

The evolution of the ‘therevoid’ clade, with an emphasis on window flies (Scenopinidae), is presented by combining DNA sequence data with morphological characters for living and fossil species. The therevoid clade represents a group of four families (Apsilocephalidae, Evocoidae, Scenopinidae and Therevidae) of lower brachyceran Diptera in the superfamily Asiloidea. A comprehensive phylogenetic analysis using parsimony and likelihood methods was undertaken using extensive taxon sampling from all families and subfamilies, and compared with outgroup taxa sampled from the related families Asilidae, Mydidae, Apioceridae and Empididae. Fifty‐nine morphological characters (adult, larval and pupal) were combined with 6.4 kb of DNA sequences for two ribosomal genes (16S and 18S ribosomal DNA) and three protein‐encoding genes [cytochrome oxidase I (COI), triose phosphate isomerase (TPI) and the CPSase region of carbamoyl‐phosphate synthase‐aspartate transcarbamoylase‐dihydroorotase (CAD)]. Results from combined analyses of morphological and molecular data for 78 taxa representing all families of the therevoid clade are presented. Specific hypotheses of the relationship between respective families and subfamilies were tested statistically using four‐cluster likelihood mapping. The therevoid clade is a well‐supported monophyletic group within Asiloidea, with Evocoidae sister to Apsilocephalidae and Therevidae sister to Scenopinidae. Temporal and zoogeographical aspects of therevoid clade evolution were investigated using Bayesian divergence time estimates and Lagrange ancestral range scenarios. The effect of inclusion of fossils as terminal taxa on phylogenetic and divergence time estimation was investigated, with morphological scoring for fossil representatives included in the analyses rather than used simply as minimum age constraints. In each analysis there was either improvement in estimation, or only marginal and localized loss in tree resolution, and with younger estimates of divergence time across the tree. The historical biogeography of the therevoid clade was examined with multiple trans‐Antarctic vicariance events between Australasia and South America evident during the Late Cretaceous to early Palaeogene. Scenopininae is newly subdivided into two tribes, Metatrichini trib.n. and Scenopinini Fallén stat.r. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:4974EBF8‐3117‐4189‐B6DE‐7D5BF9B23E53 .