<Emphasis Type="Italic">Melaleuca quinquenervia</Emphasis> dominated forests in Florida: analyses of natural-enemy impacts on stand dynamics

Melaleuca quinquenervia (melaleuca) is a native of Australia but has become an invasive plant in Florida, USA. We conducted a long-term demographic study of melaleuca in three sections (central, transitional, and peripheral) of monoculture stands located in Florida, and quantified absolute density, diameter at breast height and basal area of trees by section at three sites. Additionally, we monitored the impacts of natural enemy (insects and fungi) on melaleuca populations which became apparent after 2001. Both absolute density and basal area, from before (1997–2001) and after noticeable natural-enemy impact (2002–2005), were compared. Prior to the natural-enemy impact, absolute density of melaleuca trees declined primarily due to self-thinning and associated losses of small trees, but diameter at breast height increased, as did the basal area. Later during the period when natural enemies prevailed, absolute density declined at a significantly greater rate across all sections but was highest at the periphery. The decrease in mean absolute density and basal area/ha of melaleuca during the natural-enemy impacted period coincided with the increased incidence of the populations of plant-feeding insects and fungi. The mean diameter at breast height continued to increase in all sections of the stands throughout the study period. An increasing trend in basal area prior to natural-enemy impact was reversed after increase in natural-enemy abundance and noticeable impact in all three sections of the stands. These findings lend support to a growing body of literature that implicates natural enemies as increasingly important density-independent regulators of M. quinquenervia populations. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged     

Curculionid beetles in aborted flower buds and immature fruits of <Emphasis Type="Italic">Ceiba</Emphasis><Emphasis Type="Italic">pentandra</Emphasis> (Bombacaceae)

We determined the incidence of curculionid beetles of the genus Lonchophorus on aborted and not aborted flower buds and developing fruits of the tree Ceiba pentandra in southeastern Costa Rica. Beetle larvae were found in reproductive parts of all trees sampled trees. The frequency of beetle larvae was greater in aborted buds and immature fruits. A positive correlation between larvae development and flower bud development indicates that female oviposition occurred in an early flower developmental stage and time until bud abortion is variable. Weevil herbivory could be considered as one of the main factors that cause flower bud and fruit abortion in C. pentandra.

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Resumen Determinamos la incidencia de curculiónidos del género Lonchophorus en botones florales y frutos inmaduros tanto abortados como no abortados en el árbol Ceiba pentandra en el SE de Costa Rica. Las larvas de curculiónidos fueron encontradas en todos los árboles muestreados. La frecuencia de larvas fue mayor en botones y frutos abortados. Una correlación positiva entre el desarrollo larval y el desarrollo del botón indica que la oviposición ocurre en una fase temprana de este y que el tiempo hasta el aborto es variable. La herbivoría por larvas de curculiónidos puede ser uno de los factores más importantes en el aborto de botones y frutos inmaduros en C. pentandra.

     

Transpiration and stomatal conductance of mistletoe (<Emphasis Type="Italic">Loranthus europaeus</Emphasis>) and its host plant,downy oak (<Emphasis Type="Italic">Quercus pubescens</Emphasis>)

Sap flow rate was measured in the crown of a solitary specimen of downy oak (Quercus pubescens) infested by mistletoe (Loranthus europaeus). Five oak branches and two mistletoe plants were selected for analysis. The seasonal sum of transpired water expressed per leaf area unit was five times higher in the mistletoe than in the oak. In addition, the diurnal curves of sap flow were different between the plants. In the morning, the sap flow measured in the mistletoe lagged one hour behind the sap flow measured in an oak branch unencumbered by mistletoe. In contrast, no time lag was observed in the evening. The proportion of water transpired at night relative to the total transpiration was 7% in both species. The stomatal conductances derived from the inverted Penman-Monteith equation and their dependence on global radiation and the vapour pressure deficit (D) revealed that D exerts a different behaviour in stomatal control of transpiration in the mistletoe. We also determined that the concentration of calcium in the leaf mass could serve as a proxy for transpiration rate, however the relationship was not proportional.     

Host physiological condition regulates parasitic plant performance: <Emphasis Type="Italic">Arceuthobium vaginatum</Emphasis> subsp. <Emphasis Type="Italic">cryptopodum</Emphasis> on <Emphasis Type="Italic">Pinus ponderosa</Emphasis>

Much research has focused on effects of plant parasites on host-plant physiology and growth, but little is known about effects of host physiological condition on parasite growth. Using the parasitic dwarf mistletoe Arceuthobium vaginatum subsp. cryptopodum (Viscaceae) and its host Pinus ponderosa, we investigated whether changes in host physiological condition influenced mistletoe shoot development in northern Arizona forests. We conducted two studies in two consecutive years and used forest thinning (i.e., competitive release) to manipulate host physiological condition. We removed dwarf mistletoe shoots in April, before the onset of the growing season, and measured the amount of regrowth in the first season after forest thinning (Study I: n=38 trees; Study II: n=35 trees). Thinning increased tree uptake of water and carbon in both studies, but had no effect on leaf N concentration or δ¹³C. Mistletoe shoot growth was greater on trees with high uptake of water and carbon in thinned stands than trees with low uptake in unthinned stands. These findings show that increased resource uptake by host trees increases resources to these heterotrophic dwarf mistletoes, and links mistletoe performance to changes in host physiological condition.     

Ectomycorrhizal characterization of an American chestnut <Emphasis Type="SmallCaps">(</Emphasis><Emphasis Type="Italic">Castanea dentata</Emphasis><Emphasis Type="SmallCaps">)</Emphasis>-dominated community in Western Wisconsin

Circa 1900, a farmer from the eastern US planted 11 American chestnut (Castanea dentata) seeds on a newly established farm near West Salem in western Wisconsin. These trees were very successful, producing a large stand of over 6,000 trees. Since this area is well outside the natural range of chestnut, these trees remained free from chestnut blight until 1987. In the West Salem stand, chestnuts are the dominant species of a mixed forest community, reminiscent of the chestnut–oak ecosystems of pre-1900 Appalachia. To identify putative mycorrhizal associates of chestnut in this unique forest, our approach was twofold: (1) an extensive fruiting body survey was conducted for four seasons that yielded approximately 100 putative mycorrhizal species and (2) a belowground molecular approach was used to generate DNA sequences of the internal transcribed spacer region from ectomycorrhizae. Unexpectedly, chestnut did not appear to be the dominant underground ectomycorrhizal-forming plant species. This study highlights the need to identify the plant host species when conducting belowground molecular-based surveys and provides preliminary identification of ectomycorrhizal fungi associated with a disjunct stand of American chestnut. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Decolourisation and dephenolisation potential of selected <Emphasis Type="Italic">Aspergillus</Emphasis> section <Emphasis Type="Italic">Nigri</Emphasis> strains – <Emphasis Type="Italic">Aspergillus tubingensis</Emphasis> in olive mill wastewater

Aspergillus section Nigri strains Aspergillus aculeatus Ege-K 258, A. foeditus var. pallidus Ege-K156, A. niger Ege-K 4 and A. tubingensis Ege-K 265 were used to treat olive mill wastewater (OMW) in an investigation aimed at exploring their dephenolisation and decolourisation ability and, consequently, the economic feasibility of using any or all of these strains in a pre-treatment step in the processing of OMW. Of these strains A. tubingensis Ege-K 265 resulted in an 80% decolourisation of twofold-diluted OMW and a 30% decolourisation of undiluted OMW; in addition, it was able to remove approximately 30% of all phenolic compounds in both twofold-diluted and undiluted OMW. We conclude that A. tubingensis Ege-K 265 could be effectively used in the pre-treatment step of a combined aerobic-anaerobic process to solve the environmental problems caused by OMW in Mediterranean countries.     

A new name in <Emphasis Type="Italic">Pavetta</Emphasis> L. (<Emphasis Type="Italic">Rubiaceae</Emphasis>)

Summary  The name Pavetta modesta (Hiern) S. E. Dawson is a later homonym of P. modesta Bremek. Pavetta crystalensis is proposed as a new name.     

Improved plantlet regeneration from open-pollinated families of <Emphasis Type="Italic">Abies alba</Emphasis> trees of Dobroč primeval forest and adjoing managed stand via somatic embryogenesis

Possibility to improve plantlet regeneration from Abies alba Mill. open-pollinated families of 4 trees in Dobroč primeval and 3 trees in managed forest was studied. Immature zygotic embryos were cultured in order to obtain initiation of embryogenic tissue. Totally, three from the families of the managed forest (57%) and two from the primeval families (50%) responded to initiation condition. Initiation frequencies among families ranged in managed forest: 4.5–56.2%, primeval: 5.4–16.8%. Maturation ability was shown by 77.3% of the primeval cell lines, 36.4% cell lines produced cotyledonary somatic embryos. In managed forest, in 62.5% of the cell lines embryo maturation was observed. Cotyledonary embryos developed only in 15% of cell lines. Regenerants were obtained from 9 cell lines of primeval and from 6 cell lines of managed forest. Biochemically, the mature somatic embryos were characterized by the variation in soluble and protein profiles. The corresponding profiles of insoluble proteins exhibited uniform pattern. The variation was characteristic for somatic embryos of individual cell lines rather than for the primeval and managed stands. Enzymatically, no indications were obtained supporting higher metabolic potential of somatic embryos derived from zygotic embryos of silver fir primeval stand than in somatic embryos originating from the trees of managed stand.     

<Emphasis Type="Italic">In vitro</Emphasis> selection and regeneration of chrysanthemum (<Emphasis Type="Italic">Dendranthema grandiflorum</Emphasis> Tzelev) plants resistant to culture filtrate of <Emphasis Type="Italic">Septoria obesa</Emphasis> Syd

Callus cultures derived from leaf segments of chrysanthemum cultivar ‘Snow Ball’ which was susceptible to Septoria obesa were successfully used for in vitro selection for resistance to this pathogenic fungus. Resistant cell lines were selected by culturing callus on growth medium containing various concentrations of S. obesa filtrate. Resistant calluses obtained after two cycles (30 d each cycle) of selection were used for plant regeneration. About 30% of the plants regenerated from the resistant calluses and 70–80% of the plants raised from cuttings had acquired considerable resistance against the pathogen in the field. No phenotypic variation was observed in the selected regenerates.     

Typification of <Emphasis Type="Italic">Metrosideros regelii</Emphasis> (<Emphasis Type="Italic">Myrtaceae</Emphasis>) and consideration of its generic position

Summary  The type specimen of Metrosideros regelii is discussed. It contains a mixture of two species, representing different genera, and a lectotype is chosen. The generic position of the species is considered in the light of morphology and recent molecular evidence and the new combination, Mearnsia regelii, made.     

Two new species of <Emphasis Type="Italic">Lirula</Emphasis> on <Emphasis Type="Italic">Abies</Emphasis> from Japan

Two new species of Lirula (L. japonica and L. exigua) on Abies mariesii collected in subalpine areas of northern Japan are described as members of Rhytismatales, Discomycetes. Lirula japonica causes needle cast in fir, but L. exigua seems to occur on the needles of physically damaged twigs. Morphological characteristics of both species are discussed.     

<Emphasis Type="Italic">Septobasidium parviflorae</Emphasis> sp. nov. on <Emphasis Type="Italic">Pinus parviflora</Emphasis> from Japan

Septobasidium parviflorae sp. nov. on Pinus parviflora is described and illustrated. This species is characterized by its whitish-gray, gray to dark gray-colored fungus body with an indeterminate margin, hyphal strands, and cylindrical basidia with long sterigmata. This is the first report of Septobasidium occurring on a member of the genus Pinus in Japan.     

<Emphasis Type="Italic">Cardamine plumieri</Emphasis> (<Emphasis Type="Italic">Brassicaceae</Emphasis>) confirmed to the Flora of Serbia

The south-European Cardamine plumieri Vill. (sect. Pteroneurum subsect. Cryptopterum) is confirmed for the Flora of Serbia. Several populations were discovered in the central and western part of country, exclusively on the serpentine bedrocks. Morphological, chorological and ecological characteristics of C. plumieri was studied.     

Clustered root distribution in mature stands of <Emphasis Type="Italic">Fagus sylvatica</Emphasis> and <Emphasis Type="Italic">Picea abies</Emphasis>

Distribution of small roots (diameter between 2 mm and 5 mm) was studied in 19 pits with a total of 72 m² trench profile walls in pure stands of Fagus sylvatica and Picea abies. Root positions within the walls were marked and transformed into x-coordinates and y-coordinates. In a GIS-based evaluation, zones of potential influence around each root were calculated. The total potential influence produced isoline maps of relative root influence zones, thus indicating small root clustering. The questions studied were (1) whether there were marked clusters of small roots in the soil and (2) whether trees surrounding the pit (defined as tree density) correlate with the root abundance and distribution on the trench profile walls. Small roots of both species showed maximum abundance in the top 20 cm of the soil, where pronounced root clusters occurred next to areas with only low root accumulation. The area of root clusters did not differ significantly between the two stands. Weighted clumping, WC, calculated as a product of root class, and its area was used as an index of root clustering, which again did not differ between beech and spruce stands. However, evaluations on a single root level showed that beech achieved the same degree of clustering with lower number of roots. Regardless of soil properties related to root clusters, a significantly higher clustering acquired per root for beech than for spruce suggests beech to be more efficient in belowground acquisition of space. Because none of the parameters describing root clustering were correlated with tree density around the investigated soil profiles, clusters of small roots are inherently present within the tree stands.     

Rhizosphere competent <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> in the management of <Emphasis Type="Italic">Heterodera cajani</Emphasis> on sesame

Biological control of the cyst forming nematode Heterodera cajani was studied on sesame using plant growth promoting rhizobacteria (PGPR) Pseudomonas aeruginosa LPT3 and LPT5. Based on plant growth promoting attributes, two fluorescent pseudomonads, LPT3 and LPT5 were evaluated for their efficacy against cyst forming nematode Heterodera cajani that parasitize Sesamum indicum. Pseudomonas aeruginosa LPT5 produced IAA, HCN, chitinase, glucanase and siderophore, and also solubilized inorganic phosphate in vitro. Moreover, LPT5 resulted in mortality of second stage juveniles of H. cajani, which was 13% higher as compared to P. aeruginosa LPT3. Interestingly, when both strains were inoculated together for the management of H. cajani on Sesamum indicum the population of H. cajani was reduced significantly, in field trial. Approximately 60% reduction in cyst and juveniles population was recorded with LPT5 coated seeds, while LPT3 resulted in 49% reduction in cyst and juvenile population as compared to control. Plants grown with seeds bacterized with LPT5 and reduced doses of urea, diammonium phosphate (DAP), muriate of potash (K) and gypsum gave maximum increase in yield, in comparison to that of plants raised under the influence of recommended or full doses of the chemical fertilizers. Pseudomonas aeruginosa LPT5 also showed excellent root colonization.     

Feeding Ecology of <Emphasis Type="Italic">Propithecus diadema</Emphasis> in Forest Fragments and Continuous Forest

Forest fragmentation is viewed as a serious threat to primates, yet whether or not it can disrupt food resources and cause energetic stress remains largely untested. I present the results of a 12-mo study of the feeding ecology of Propithecus diadema in fragmented and continuous forest at Tsinjoarivo, eastern Madagascar. Two continuous forest groups had higher dietary diversity and ate more fleshy fruit, but during the dry season, diversity was reduced and they relied heavily on mistletoe (Bakerella clavata). In contrast, 2 groups in fragments employed the lean season strategy of eating mistletoe year-round; the fruiting tree species that sustain continuous forest groups through the rainy season were largely absent. As expected, intersite dietary overlap was highest in the dry season. The level of specialization was high: fragment groups devoted 30–40% of feeding time to Bakerella clavata, compared to 28–30% in continuous forest. The major characteristic of Bakerella clavata enabling it to be an important fallback or staple resource, or both, is its extended phenology. The difference in resource utilization between sites may have important implications for nutritional status, as well as ranging and social behavior, largely owing to the small size and high abundance of feeding patches of Bakerella. Understanding resource shifts in fragments can shed light on socioecological questions by providing comparisons between continuous forest and fragment populations with differing diets and resource distributions. In addition, understanding dietary shifts in fragments can aid in species-specific conservation efforts, while contributing to a better understanding of the considerable interspecific variability of primates in responses to fragmentation.     

Overexpression of <Emphasis Type="Italic">WUSCHEL</Emphasis> in <Emphasis Type="Italic">C. chinense</Emphasis> causes ectopic morphogenesis

Capsicum chinense is a recalcitrant species for in vitro morphogenesis, and up to date there is no efficient system for genetic transformation and regeneration of this species via somatic embryogenesis. Here, we carried out an in vitro transformation of C. chinense via Agrobacterium tumefaciens co-cultivation with a system that expresses the heterologous gene WUSCHEL from Arabidopsis thaliana. WUSCHEL has been shown to promote the transition from vegetative to embryogenic state when overexpressed. We tested if the expression of WUSCHEL in C. chinense would promote an embryogenic response in this species. After 15 days of induction, the segments of transformed stems begun to form globular structures, suggesting that heterologus WUSCHEL was active and involved in the process of morphogenesis.     

Ecological conditions and the distribution of alpine juniper (<Emphasis Type="Italic">Juniperus communis</Emphasis> subsp. <Emphasis Type="Italic">alpina</Emphasis>) in the Hrubý Jeseník Mts

In the Hruby Jeseník Mts of the Czech Republic, research was carried out from 2001–2005 aimed at completing an up-to-date census of alpine juniper [Juniperus communis subsp. alpine (Smith) Čelakovsky] and an evaluation of the overall health status of the populations, and at investigating the impacts of the main environmental factors on the viability of this species. 13 sites were identified with 283 individuals in total, but the sites differed dramatically in the number of recorded individuals. Comparisons with historical literature sources show that the species has been in decline. The main reasons for this decline include: a lack of suitable sites for colonization connected with a lack of adequate disturbance factors, competition from shading trees, and the presumed high age of the juniper populations combined with zero generative reproduction. More than two thirds of the individuals showed slight damage to their assimilation system. A health status of bad or very bad was determined for 5 % of the alpine juniper individuals. These trees in the Hruby Jeseník Mts are also exposed to pressure from some herbivore insects and mammals. The populations are not yet in a literally critical state, but considering the range of impacts affecting them, it will be necessary to pay significant attention to their conservation strategies. Some recommendations for future management are suggested.     

Muscular architecture of <Emphasis Type="Italic">Milnesium tardigradum </Emphasis>and <Emphasis Type="Italic">Hypsibius </Emphasis>sp. (Eutardigrada,Tardigrada) with some data on <Emphasis Type="Italic">Ramazottius oberhaeuseri</Emphasis>

The architecture of the musculature of the eutardigrade species Milnesium tardigradum Doyère, 1840, Hypsibius sp. and Ramazzottius oberhaeuseri (Doyère in Ann Sci Nat Zool Sér 2(14):269–369, 1840) is investigated by phalloidin staining and confocal laser scanning microscopy. There are methodological problems in staining eutardigrades due to physiological alterations under stress (anhydrobiosis) and due to penetration problems of the cuticle. It is helpful to fix specimens in the state of asphyxy, where animals are stretched following an oxygen shortage in their environment. The musculatures of all three species correspond in their general architecture, but differ in detail, such as in the number of muscles. All muscles are isolated muscle strands. There are on each body side two dorsal and one ventral muscle strands, in addition to a system of dorsoventral, lateral and lateroventral muscles. Seven median ventral attachment points give rise to dorsoventral, ventrolateral and appendage muscles. The appendages receive several muscles originating dorsally and ventrally. The number of muscles and the arrangement differ in each appendage. The fourth appendage shows the greatest differences with a far smaller number of muscles compared to other species. The musculature shows comparably few strict segmental patterns, for example, the musculature of each appendage differs from the other ones. By comparison with literature data on the same species and data of Macrobiotus hufelandi it can be shown that eutardigrades have a roughly comparable muscular architecture, but that there are several differences in detail. Dedicated to Professor Westheide on the occasion of his 70th birthday.