Pollen profiles from three former lakes in the Lake Garda area

1. Late glacial and postglacial sediments from three former lakes in the Lake Garda area (Southern Alps) were investigated. 2. The pollen diagram from Bondone (1550 m) shows an older phase rich in NAP. A younger one corresponds with the Younger Dryas time according to two radiocarbon determinations. In the Preboreal no climatic deterioration could be found. 3. At first plants, which are nowadays typical for snow-ground, pioneer and dwarf shrub associations, immigrated into the surroundings of Bondone. In Alleröd times larch and pine appeared as the first trees. At the beginning of the Preboreal dense forest existed in that region. During the Alleröd timber line was at about 1500 m. 4. In the pollen diagrams from Saltarino (194 m) and Fiavè (654 m) an oldest period rich in NAP is followed by two stadial and two interstadial phases. Tree birches and larches immigrated during the oldest interstadial phase. 5. In the case of Saltarino and Fiavè only a preliminary dating could be made. A correlation seems to be possible with diagrams published by Zoller as well as with the diagram of Bondone. Discrepances in dating, which arise then, are discussed. According to the two possibilities of dating the youngest stadial is synchronous either with the so-called Piottino stadial or the Younger Dryas time. Consequently the oldest interstadial phase of Saltarino corresponds either with the Bölling or with a pre-Bölling interstadial. The last possibility seems to be more probable. 6. In the southern part of the Lake Garda area reforestation was preceded by a long shrub phase mainly with Juniperus. At about 650 m there was a period with Pinus mugo and only with a small amount of Juniperus before reforestation. A phase with Betula nana well known from areas north of the Alps could nowhere be found. 7. In the area under study larch appeared as the first tree. Lateron it has been the most important constituent of the forests near timber line. Birch, which plays an important role as a pioneer tree in Denmark - for instance at the transition of the pollen zones III/IV - as well as in Southern Germany during Bölling time, was of less importance at the southern border of the Alps. In that area the spreading of Pinus occurred very early causing dense forests. 8. During the last stadial phase (probably Younger Dryas time) dense forests with Pinus and Larix existed at 650 m. In the lower part of the Lake Garda area, however, both thermophilous trees as Quercus and herbs frequently occurred. This leads to the conclusion that during this time tree growth was limited by dryness in lower altitudes of the border of the Southern Alps. Pinus and Juniperus, however, do not show higher values in this period, a fact which cannot yet be explained. 9. A list of plants, which were found in the sediments, is compiled. Helodium lanatum, Dictamnus albus, Mercurialis cf. ovata, Buxus, Cerinthe cf. minor, Onosma, Anthericum and Asphodelus albus are findings, which are of special interest for the history of the flora of that region.

Broad Bean Stain Virus: Identification, Detectability with ELISA in Faba Bean Leaves and Seeds, Occurrence in West Asia and North Africa and Possible Wild Hosts

Abstract During a survey of faba bean viruses in West Asia and North Africa a virus was identified as broad bean stain virus (BBSV) based on host reactions, electron microscopy, physical properties and serology. An antiserum to a Syrian isolate was prepared. With this antiserum both the direct double antibody sandwich ELISA (DAS-ELISA) and dot-ELISA were very sensitive in detecting BBSV in leaf extracts, ground whole seeds and germi nated embryos. Sens it i vity was not reduced when the two-day procedure was replaced by a one-day procedure. us i ng ELISA the vi rus was detected in 73 out of 589 faba bean samples with virus-like symptoms collected from Egypt (4 out of 70 samples tested), Lebanon (6/44) , Morocco (017), Sudan (19/254), Syria (36/145) and Tunisia (8/69). This is the first report of BBSV infection of faba bean in Lebanon, Sudan, Syria and Tunisia. speci es i ndi genous to Syri a were Fourteen wild legume susceptible to BBSV infection, with only two producing obvious symptoms. The virus was found to be seed transmitted ~n Vicia palaestina.

Can rodents enhance germination rates in rainforest seeds?

The decline of large coevolved frugivorous species within fragmented habitats can have an effect on ecological processes, for example, seed dispersal and germination. It is therefore necessary for more resilient species to ensure essential processes are maintained within the system. This study investigates the influence of two rodent species, Melomys cervinipes (Fawn-footed Melomys) and Rattus fuscipes (Bush Rat), on the germination process of rainforest fruits. Both species are endemic to north Queensland rainforest and commonly found in fragmented habitats in high densities. We found in 85% of fruit species tested, rodent feeding increased seed germination rate by a factor of 3.5. Our results suggest that rodents can play a significant role in enhancing germination rates of fruits in the tropical rainforest of far north Queensland.

Pyrolysis decomposition of mahogony seeds (Swietenia macrophylla) for alternative fuel oil

A fixed bed pyrolysis has been designed and fabricated for obtaining liquid fuel from Mahogany seeds. The major components of the system are fixed bed pyrolysis reactor, liquid condenser and liquid collectors. The Mahogany seed in particle form is pyrolysed in an externally heated 10 cm diameter and 36 cm high fixed bed reactor with nitrogen as the carrier gas. The reactor is heated by means of a biomass source cylindrical heater from 450oC to 600oC. The products are oil, char and gas. The reactor bed temperature, running time and feed particle size are considered as process parameters. A maximum liquid yield of 54wt% of biomass feed is obtained with particle size of 1.18 mm at a reactor bed temperature of 5500C with a running time of 90 minutes. The oil is found to possess favorable flash point and reasonable density and viscosity. The higher calorific value is found to be 39.9 MJ/kg which is higher than other biomass derived pyrolysis oils.

Seeds of cosmopolitan future? Young people and their aspirations for future mobility

Mobility across space is an exemplary characteristic of the global era and an important aspect of the cultural experience of many people in advanced industrialised nations. Mobility evokes powerful images that effectively counter any illusion of stationary life and provide a break from the insularity of the local and parochial. High levels of mobility are simultaneously a fact, a necessity and a cultural aspiration. In recent times, debates about mobility in social theory have considered the relationship between mobility and cosmopolitan culture and identities (Hannerz, 1990, Urry, 1990, 2000, Beck, 2006). Against this backdrop, this paper also draws on some of the more recent discussions about the emergence of globalised and cosmopolitan identities among young people (Beck and Beck-Gernsheim, 2009). Using data from a longitudinal study of young people in Queensland, this paper provides an insight into young people’s aspirations about future mobility. The data affirm Skeggs’ (2004) comment that mobility is an unequal resource, and demonstrate that aspirations of future mobility reflect numerous social, economic and cultural realities of young people’s lives. This inevitably leads us to problematise the established, and often abstract, nexus between cosmopolitanism and mobility in contemporary debates about cosmopolitanism.

Anatomical studies of the flower, fruit and seeds of Myrceugenia rufa (Myrtaceae)

Myceugenia rufa is a rare and endemic species from the coast of central Chile. There are no published studies describing flower, fruit or seed anatomy. Forty-two accessions were collected from across the geographic range of the species. Reproductive structures were fixed, dehydrated, embedded in paraffin, sectioned and stained with Safranin O and Fast green. Anatomy of floral buds, mature flowers, fruits and seeds was described. Reproductive anatomy matches that of other Myrtaceae, such as presence of druses, internal phloem and schizogenous secretory cavities in buds, flowers, fruits and seeds. The anatomy and development of reproductive structures of M. rufa might enhance the understanding for future studies regarding natural reproduction and conservation programs.

Homology between jacalin and artocarpin from jackfruit (Artocarpus integrifolia) seeds. Partial sequence and preliminary crystallographic studies of artocarpin

Jacalin and artocarpin, the two lectins from jackfruit (Artocarpus integrifolia) seeds, have different physicochemical properties and carbohydrate-binding specificities. However, comparison of the partial amino-acid sequence of artocarpin with the known sequence of jacalin indicates close to 50% sequence identity. Artocarpin crystallizes in two forms, both monoclinic P2(1), with one and two tetramic molecules, respectively, in the asymmetric units of form I (a = 69.9, b = 73.7, c = 60.6 Angstrom and beta = 95.1 degrees) and form II (a = 87.6, b = 72.2, c = 92.6 Angstrom and beta = 101.1 degrees). Both the crystal structures have been solved by the molecular replacement method using the known structure of jacalin as the search model and ope of them partially refined, confirming that the two lectins are indeed homologous.

A soluble preparation from developing groundnut seeds (Arachis hypogaea) catalyzes de novo synthesis of long chain fatty acids

A 100,000 x g supernatant fraction prepared from developing groundnut seeds (30-35 days after flowering) catalyzed the synthesis of fatty acids from [l-14C]acetate at a rate of 120nmoles of acetate incorporated per hr per gram fresh weight of tissue. 90% of this incorporated label was associated with fatty acids. The major fatty acids formed were stearic- (77%) and palmitic acids (14%) with 4% of oleic acid. The fatty acid synthetase activity was stable when stored at 0-4 degrees C for at least fifteen days. It is concluded from these results that acetyl-coA carboxylase and all the enzymes of fatty acid synthetase from developing groundnut seeds are soluble.

Differing mechanisms of simple nitrile formation on glucosinolate degradation in Lepidium sativum and Nasturtium officinale seeds.

Glucosinolates are sulphur-containing glycosides found in brassicaceous plants that can be hydrolysed enzymatically by plant myrosinase or non-enzymatically to form primarily isothiocyanates and/or simple nitriles. From a human health perspective, isothiocyanates are quite important because they are major inducers of carcinogen-detoxifying enzymes. Two of the most potent inducers are benzyl isothiocyanate (BITC) present in garden cress (Lepidium sativum), and phenylethyl isothiocyanate (PEITC) present in watercress (Nasturtium officinale). Previous studies on these salad crops have indicated that significant amounts of simple nitriles are produced at the expense of the isothiocyanates. These studies also suggested that nitrile formation may occur by different pathways: (1) under the control of specifier protein in garden cress and (2) by an unspecified, non-enzymatic path in watercress. In an effort to understand more about the mechanisms involved in simple nitrile formation in these species, we analysed their seeds for specifier protein and myrosinase activities, endogenous iron content and glucosinolate degradation products after addition of different iron species, specific chelators and various heat treatments. We confirmed that simple nitrile formation was predominantly under specifier protein control (thiocyanate-forming protein) in garden cress seeds. Limited thermal degradation of the major glucosinolate, glucotropaeolin (benzyl glucosinolate), occurred when seed material was heated to >120 degrees C. In the watercress seeds, however, we show for the first time that gluconasturtiin (phenylethyl glucosinolate) undergoes a non-enzymatic, iron-dependent degradation to a simple nitrile. On heating the seeds to 120 degrees C or greater, thermal degradation of this heat-labile glucosinolate increased simple nitrile levels many fold.

Effect of foliar herbicides on the germination and viability of Siam weed (Chromolaena odorata) seeds located on plants at the time of application.

This paper reports a field study undertaken to determine if the foliar application of herbicides fluroxypyr (150 mL 100 L-1 a.i.) and metsulfuron-methyl (12 g 100 L-1 a.i.) were capable of reducing the germination and viability of Chromolaena odorata (L.) R.M.King & H.Rob. (Siam weed) seeds at three different stages of maturity. After foliar application of fluroxypyr germination of mature seeds was reduced by 88% and intermediate and immature seeds were reduced by 100%, compared to the control. Fluroxypyr also reduced the viability of mature, intermediate and immature seeds by 79, 89 and 67% respectively, compared to the control. Metsulfuron-methyl reduced germination of intermediate and immature seeds by 53 and 99% respectively compared to the control. Viability was also reduced by 74 and 96% respectively, compared to the control. Mature seeds were not affected by metsulfuron-methyl as germination and viability increased by 2% and 1% respectively, as compared to the control. These results show that these herbicides are capable of reducing the amount of viable seed entering the seed bank. However depending on the treatment and stage of seed development a percentage of seeds on the plants will remain viable and contribute to the seed bank. This information is of value to Siam weed eradication teams as plants are most easily located and subsequently treated at the time of flowering. Knowledge of the impact of control methods on seeds at various stages of development will help determine the most suitable chemical control option for a given situation.

Fruit traits of vertebrate-dispersed alien plants: smaller seeds and more pulp sugar than indigenous species

Vertebrates play a major role in dispersing seeds of fleshy-fruited alien plants. However, we know little of how the traits of alien fleshy fruits compare with indigenous fleshy fruits, and how these differences might contribute to invasion success. In this study, we characterised up to 38 fruit morphology, pulp nutrient and phenology traits of an assemblage of 34 vertebrate-dispersed alien species in south-eastern Queensland, Australia. Most alien fruits were small (81%\15 mm in mean width), and had watery fruit pulps that were high in sugars and low in nitrogen and lipids. When compared to indigenous species, alien fruits had significantly smaller seeds. Further, alien fruit pulps contained more sugar and more variable (and probably greater) nitrogen per pulp wet weight, and species tended to have longer fruiting seasons than indigenous species. Our analyses suggest that fruit traits could be important in determining invasiveness and could be used to improve pre- and post-border weed risk assessment.

Contagious dispersal of seeds of synchronously fruiting species beneath invasive and native fleshy-fruited trees

In subtropical Australia, many native and invasive plant species rely on a shared suite of frugivores, largely birds, for seed dispersal. Many native plants fruit during summer in this region, whereas most invasive plants fruit during winter, thus providing the opportunity for contagious dispersal of seeds beneath synchronously fruiting species. We sampled invasive and native seed rain beneath the canopy of a native summer-fruiting tree Guioa semiglauca and an invasive winter-fruiting tree Cinnamomum camphora, in three study sites over the course of a year. In July, during peak fruiting season for C. camphora and other invasive species, seed rain of invasive species was higher beneath C. camphora than G. semiglauca. This was partly due to the invasive tree Ligustrum lucidum, whose seed rain was three times higher beneath C. camphora than beneath the native tree. In February, seed rain of native species was more abundant beneath the canopy of G. semiglauca than beneath C. camphora, despite the fact that C. camphora was also fruiting at this time. This was probably due to the larger fruit crop produced by G. semiglauca at this time of year. Our study provides evidence that the presence of invasive bird-dispersed plants may facilitate contagious seed dispersal of other invaders, and likewise native species may facilitate seed spread of other native plants.