Soil springtails (Hexapoda: Collembola), symphylans and pauropods (Arthropoda: Myriapoda) under different management systems in agroecosystems of the subhumid Pampa (Argentina)

The Pampa region is the most important agricultural area in Argentina. Although intensive agricultural activity is leading to important levels of soil degradation, studies on the impact on soil fauna are scarce. Despite the environmental importance of collembolans, symphylans and pauropods in soil, information on the influence of land management on their population densities is poor, particularly in Neotropical agroecosystems. The aim of this study was to investigate the effects of different management systems on the density of collembolans, symphylans and pauropods. Population abundance of these arthropods was examined in a natural site and a cattle raising, a mixed and an agricultural management system on a Typic Hapludoll soil in La Colacha, Córdoba, Argentina. All the sites studied had the same land use history until approximately 50 years before sampling and have the same soil type. Total abundance of the studied groups varied in the different management systems. Our results suggest that conventional agricultural management tends to reduce the density of collembolans and pauropods. Our data do not support our hypothesis that the cattle raising management system constitutes an intermediate situation between the natural site and the high-input management systems. We conclude that the reduction of collembolan and pauropod densities in high-input management systems is largely explained by the mechanical and chemical perturbations produced by conventional agricultural management practices and by particular abiotic soil conditions present in the intensively managed sites that are unfavourable for these organisms. Surprisingly, symphylans were more abundant in the mixed management site. The implications of our findings on soil ecosystem functioning are discussed.     

The influence of different vegetation patches on the spatial distribution of nests and the epigeic activity of ants (Lasius niger) on a spoil dump after brown coal mining (Czech Republic)

A study was carried out during 2001 on mine tailings in NW Bohemia aimed at describing the spatial patterns of nests distribution and epigeic activity of ants in relation to the vegetation mosaic. Lasius niger was the most abundant species of ant and its nest mounds were significantly more numerous in patches with sparse vegetation than inside dense Calamagrostis epigejos vegetation; this was particularly true for small and medium-sized nests. Small and medium nests also occurred more frequently near the edges of a given patch than in the center. Large and medium nests were randomly distributed in the area, whereas small nests had an aggregated distribution. Pitfall trapping reveal significantly higher activity of L. niger workers in tall and dense vegetation stands in comparison with low and sparse vegetation. This pattern was particularly pronounced during the peak of foraging activity in summer and was not so significant in spring or autumn. We expect that ant preferentially forage in shaded habitats during the summer months when bare soil may be too hot. The results indicated that nesting and foraging may differ in their microclimatic requirements and the formation of vegetation mosaics may be important to changes in the ant population during succession.     

Intra-specific DNA polymorphism in pineapple (<Emphasis Type="Italic">Ananas comosus</Emphasis> (L.) Merr.) assessed by AFLP markers

Pineapple (Ananas comosus (L.) Merr.) cultivars, often derived from somatic mutations, are propagated vegetatively. It has been suggested by isozyme data that there is little genetic variation among Smooth Cayenne cultivars. A thorough investigation of the genetic variation within the cultivated speciesAnanas comosus, particularly among commercial cultivars, will provide critical information needed for crop improvement and cultivar protection. One-hundred and forty-eight accessions ofA. comosus and 14 accessions of related species were evaluated with AFLP markers. The average genetic similarity ofA. comosus was 0.735 ranging from 0.549 to 0.972, suggesting a high degree of genetic variation within this species. With AFLP markers, discrete DNA fingerprints were detected for each commercial cultivar, breeding line, and intra-specific hybrid. Self-incompatibility, high levels of somatic mutation, and intraspecific hybridization may account for this high degree of variation. However, major cultivar groups of pineapple, such as Cayenne, Spanish, and Queen, could not be distinctively separated. These cultivar groups are based on morphological similarity, and the similar appearance can be caused by a few mutations that occurred on different genetic background. Our results suggest that there is abundant genetic variation within existing pineapple germplasm for selection, and discrete DNA fingerprinting patterns for commercial cultivars can be detected for cultivar protection. The genetic diversity and relationships of fourAnanas species are also discussed.     

Community composition of ammonia-oxidizing bacteria in the rhizosphere of intercropped wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.), maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.), and faba bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.)

Cereal/cereal and cereal/legume intercropping systems are popular in the north, northwest, and southwest of China and often result in yield increases compared to monocropping. Rhizosphere interactions may play a significant role in the yield increases, particularly with respect to nutrient availability. The aim of this study was to investigate the effects of intercropping on N availability and community composition of ammonia-oxidizing bacteria in the rhizosphere of wheat, maize, and faba bean at different growth stages. Denaturing gradient gel electrophoresis (DGGE) based on 16S rRNA genes was used to analyze the community composition of bacterial ammonia oxidizers belonging to β-proteobacteria. The results showed that intercropping with faba bean significantly increased nitrate concentrations in the rhizosphere of wheat and maize at the second sampling time (20 June) compared to monocropping or intercropping between maize and wheat. Intercropping significantly affected the community composition of ammonia-oxidizing bacteria in the rhizosphere compared to monocropping, and the effects were most pronounced in the maize/faba bean and wheat/maize intercropping systems when faba bean and wheat were at anthesis and maize was in seedling stage. In wheat/faba bean intercropping, the effects of intercropping on community composition of ammonia-oxidizing bacteria were less pronounced at the seedling stage of the two species but were significant at anthesis.     

The Corsican citron melon (<Emphasis Type="Italic">Citrullus lanatus</Emphasis> (Thunb.) Matsum. et Nakai subsp. <Emphasis Type="Italic">lanatus</Emphasis> var. <Emphasis Type="Italic">citroides</Emphasis> (Bailey) Mansf. ex Greb.) a traditional and neglected crop

During a collecting mission in Corsica (France) three landraces of citron melon (Citrullus lanatus (Thunb.) Matsum. et Nakai subsp. lanatus var. citroides (Bailey) Mansf. ex Greb.) were collected in the northern areas. Today in Corsica this old and neglected crop is in decline and risks extinction. A strategy for its characterization and safeguarding is in progress at the genebank of IGV of Bari (Italy).     

Is Hormogaster elisae (Oligochaeta,Hormogastridae) a predator of mites and springtails?

The aim of this work was to determine whether the endogeic earthworm Hormogaster elisae [1] is involved in the active or passive predation of microarthropods at El Molar (Madrid, Spain). Different techniques were employed to study the gut content, and the casts of H. elisae earthworms cultivated in the laboratory. The casts consisted mainly of mineral particles and plant remains as well as a few microarthropods, nematodes and their remains. The gut contents were similar in composition, although no microarthropod remains were found, except for a single springtail (order Poduromorpha) in one earthworm's gizzard. The results suggest that H. elisae may accidentally ingest microarthropods along with soil. The microarthropods found in the casts may have colonized them after their deposition since none were found in isolated casts.     

Selective feeding of the earthworm Hormogaster elisae (Oligochaeta,Hormogastridae) in laboratory culture

Selective feeding of the earthworm Hormogaster elisae was investigated by granulometric analysis, chemical fractionation and physical fractionation of the soil in which representatives were cultivated, and of their casts. H. elisae behaved as an endogeic species, mainly consuming soil from which it weakly but positively selected the organic fractions of greatest size (mainly free organic matter) and negatively selected the largest mineral fraction (coarse sand). No significant selection of intermediate size fractions was recorded. The 0–2 μm granulometric fraction (clays) was also selected; the results suggest that some of the organic components of this size fraction can also be used by the species.     

The impact of cattle pasturage on small annelids (Annelida: Enchytraeidae,Tubificidae, Aeolosomatidae) in grasslands of the White Carpathians (Czech Republic)

Small soil-dwelling annelids (Enchytraeidae, Tubificidae, Aeolosomatidae) were investigated at two sites in the White Carpathians (Czechia), each consisting of one meadow and one cattle pasture. Sampling was conducted on four dates during a 1-year period (2002–2003). Enchytraeid species numbers ranged from 11 to 17, with more species found in the meadows. The most abundant species were Enchytraeusbuchholzi s. l., Fridericiaisseli, Fridericiasemisetosa, Fridericiagalba, Fridericiabulboides, Fridericiabisetosa, Cernosvitoviellaminor (in the meadows), and Achaeta spp. (in one of the pastures). Henlea spp. preferred the pastures. Rhyacodrilusfalciformis was recorded in all plots, Aeolosomahemprichi and A. cf. niveum in one meadow plot. Enchytraeid densities reached up to 13 750 individuals m⁻², later drought led to much lower values. Densities were generally higher in meadows than in pastures. The vertical distribution differed between meadows and pastures: higher percentages of individuals were present in the upper 6 cm of pasture soil.     

Genetic diversity of <Emphasis Type="Italic">Guizotia abyssinica</Emphasis> (L. f.) Cass. (Asteraceae) from Ethiopia as revealed by random amplified polymorphic DNA (RAPD)

Genetic diversity of 70 populations of niger (Guizotia abyssinica) representing all its growing regions in Ethiopia was investigated using random amplified polymorphic DNA (RAPD) to reveal the extent of its populations genetic diversity. Ninety-seven percent of the loci studied was revealed to be polymorphic for the whole data set. The within population diversity estimated by Shannon diversity index and Nei gene diversity estimates was revealed to be 0.395 and 0.158, respectively. The extent of genetic variation of populations from major niger producing regions was significantly lower than that of populations from other regions; however, it is distributed regardless of altitude of growth. Genetic differentiation between populations was estimated with Shannon index as G^′ _ST (0.432), Nei’s G _ST (0.242) and AMOVA based F _ST (0.350) and appears to be equivalent to the average values calculated from various RAPD based studies on outcrossing species. Higher proportion of the variation detected by AMOVA resided within populations (64.58%) relative to the amount of variation among populations (35.42%). UPGMA cluster analysis showed that most of the populations were clustered according to their region of origin. However, some populations were genetically distant from the majority and seem to have unique genetic properties. It is concluded that the crop has a wide genetic basis that may be used for the improvement of the species through conventional breeding and/or marker assisted selection. Collection of germplasm from areas not yet covered and/or underrepresented is the opportunity to broaden the genetic basis of genebank collection.     

Symptome von Mangan-Überschuß bei Bohnen (Phaseolus vulgaris)

Symptoms of manganese toxicity in beans (Phaseolus vulgaris L) In water culture experiments with bush bean plants (Phaseolus vulgaris L. var. ?Red Kidney”?) the macro- and micro-symptoms of manganese toxicity had been studied. Typical symptoms of Mn toxicity are small distinct blackish-brown spots, first at the older leaves and at more severe toxicity also at the petals and stems. Using the autoradiographic technique on ⁵⁴Mn-distribution and comparing this with corresponding light microscopic studies it could be demonstrated that the blackish-brown spots in the leaves resemble Mn-precipitations. These precipitations are Mn-compounds of higher oxidated form and are primarily localized in the walls of cells in vicinity of the vessels. The extend to which these precipitations occur is not only a function of the Mn-content of the leaves but also of their age. At comparable Mn-content the extend of the precipitation increases with the leaf age. As secondary symptom of Mn-toxicity under certain conditions (presence of silicon e.g.) induced Fe deficiency (chlorosis of the youngest leaves) and Ca deficiency (?crinkle leaf”?) may occur. It is assumed that the process of Mn precipitation within the leaves is enzymatically regulated. The severe reduction in the growth of leaf blades at Mn toxicity is presumably related to an interference with the growth hormon balance.     

Agrobiodiversity of eleven accessions of <Emphasis Type="Italic">Mucuna pruriens</Emphasis> (L.) DC. var. <Emphasis Type="Italic">utilis</Emphasis> (Wall. ex Wight) Baker ex Burck (velvet bean) collected from four districts of South India

Eleven accessions of an under-utilized legume, Mucuna pruriens (L.) DC. var. utilis (Wall. ex Wight) Baker ex Burck (velvet bean) were collected from four districts of South India and their agronomic characters were evaluated. The vegetative growth characters such as the germination percentage, plant height, number of leaves and branches per plant were recorded. The yield based characters such as the number of clusters/plant (4–14), number of flowers/cluster (3–15) and the fertility index (66–91%) were observed. The seed yield reaches 2.9–6.9 t/ha. The number of seeds per pod, seed weight and the seed recovery percentage were also calculated. The level of diversity in the agrobotanical traits of velvet bean observed in the present study could be of interest in a breeding programme.     

Influence of size and partner preference on the female function of the earthworm Eisenia andrei (Oligochaeta,Lumbricidae)

Many aspects of the reproduction and mating behaviour of earthworms remain poorly understood. In this study, we focused on body size as a possible trait that influences earthworm reproduction and mating processes. Eisenia andrei is a simultaneously hermaphroditic animal with reciprocal insemination and many hermaphrodites are expected to mate not primarily to get their own eggs fertilized, but rather to get the opportunity to fertilize the eggs of their partners. We investigated whether E. andrei has a size-dependent sex allocation, i.e. if larger earthworms are more biased toward female allocation and produce more egg mass and whether E. andrei has a size-related mate choice by studying the relationship between mating delay and cocoon production. To test this, we compared cocoon production between pairs of earthworms of equal and different size. Mature individuals of E. andrei were classified in two size classes (small and large) and we performed a two-factorial experiment with earthworm size and the size of the partner as factors. After copulation, earthworms were isolated and thereafter their mass and the number of cocoons they produced were recorded weekly for 18 weeks. We found no evidence of size-dependent sex allocation and we found no effect of size-assortative mating on cocoon production. With respect to the differences in the time to mate, the mating delay seems to indicate the existence of some kind of mate choice, independent of the earthworm size. Those earthworms that were matched sooner laid many cocoons, but those that waited a long time to mate laid fewer cocoons. This effect was stronger in those individuals paired with large partners, suggesting that some large partners are more desired ‘males’ than others; the reason for this remain as an open question. In general, our results confirm that earthworms are able to discriminate their partners and adjust their breeding effort accordingly.     

Genetic diversity and relationships among safflower (<Emphasis Type="Italic">Carthamus tinctorius</Emphasis> L.) analyzed by inter-simple sequence repeats (ISSRs)

Genetic diversity and relationships among 48 safflower accessions were evaluated using 22 inter-simple sequence repeats (ISSR) primers. A total of 429 bands were amplified, and 355 bands (about 82.7%) were polymorphic. Five to forty-one polymorphic bands could be amplified by each primer, with an average of 16.1 polymorphic bands per primer. The results showed that the polymorphism of the safflower germplasm was higher at the DNA level. All the 48 accessions could be distinguished by ISSR markers and were divided into 9 groups based on ISSR GS by using UPGMA method. The genetic relationships among the accessions from different continents were closer. Comparatively, the genetic diversity of the accessions originated from Asia was higher, from Europe assembled. The results also showed that the genetic variation of accessions from Indian and Middle Eastern safflower diversity centers were relatively higher. ISSR is an effective and promising marker system for detecting genetic diversity among safflower and give some useful information on its phylogenic relationships.     

Assessment of Genetic Diversity among Finger Millet (<Emphasis Type="Italic">Eleusine coracana</Emphasis> (L.) Gaertn.) Accessions using Molecular Markers

Finger millet (Eleusine coracana), an allotetraploid cereal, is widely cultivated in the arid and semiarid regions of the world. Being rich in protein and calcium, finger millet serves as an important staple food for rural populations in developing tropical countries where calcium deficiency and anemia are wide spread. Thirty-two finger millet genotypes were fingerprinted using 50 random amplified polymorphic DNA (RAPD) markers. Out of the total 529 loci generated using the 50 RAPD primers, 479 loci (91%) were polymorphic and informative to differentiate the accessions. Cluster analysis grouped the 32 finger millet accessions into two major clusters. Among the 32 finger millet genotypes, GEC 182 and CO 12 were distantly related with a low similarity index of 0.315. These two accessions also differed considerably in days to flowering and grain weight; GEC 182 is early flowering and has bold grains, while CO 12 is late flowering and has smaller grains. These two accessions with higher diversity at molecular level, phenology and grain weight will be ideal as parents in hybridization programme, to develop improved finger millet varieties suitable for peninsular region of India.     

Genetic profiling of bacterial communities from the rhizospheres of ozone damaged Malva sylvestris (Malvaceae)

The phytotoxicity of tropospheric ozone at elevated concentrations can cause severe effects on plant vegetation. This study analyzed whether ozone-damaged plants transmit signals into the soil and thereby affect the structural diversity of bacteria inhabiting the rhizosphere. To generate highly stressful conditions, Malva sylvestris was raised from seeds under ozone exposure. Additionally, the plant age at the onset of ozone-stress was varied. Rhizosphere bacterial communities were analyzed by single-strand conformation polymorphism (SSCP) of PCR amplified partial 16S ribosomal RNA genes. None of these vigorous stress conditions caused a change in the genetic profiles targeting Bacteria with primers hybridizing to highly conserved regions in the 16S rRNA genes, despite visibly ozone-triggered injuries of the leaves and a reduced root biomass. Differences in the SSCP profiles however were observed between plants of different ages. In a more realistic scenario, plants raised in the greenhouse under normal atmospheric conditions were exposed to ozone episodes as they can occur during summer in industrialized countries of the northern hemisphere. To increase the sensitivity of detection, genetic profiles representing Alphaproteobacteria, Actinobacteria and Pseudomonas were analyzed separately in addition to those of Bacteria. None of the profiles showed any ozone-related alterations. In summary, the results of this study indicated that, even when the plants were visibly injured by ozone, the stress was not transmitted to the soil in a way that affected the structural diversity of the dominant rhizosphere bacterial community.     

Ecophysiology of the cave isopod Mesoniscus graniger (Frivaldszky, 1865) (Crustacea: Isopoda)

Feeding biology and thermal adaptations of the terrestrial isopod Mesoniscus graniger were studied. M. graniger is a depigmented isopod mainly inhabiting cave systems, although it has also been reported in endogeic (soil) habitats. Physiological adaptations are expected to reflect the unique environmental characteristics of caves, including restricted food sources, and stable microclimate with temperatures not exceeding about 10 °C and high relative humidity. The M. graniger from Domica and Ardovská caves (Slovakian Karst) were investigated. We identified organic deposits with associated microorganisms as sources exploited by M. graniger and assessed how these might supply essential polyunsaturated fatty acids (PUFA) in its nutrition. Algae, fungi and bat guano were found as the most important potential resources of PUFA for isopods. Digestive enzymes amylase, trehalase, saccharase and maltase were confirmed in the whole body homogenates of isopods; neither cellulolytic activity nor activities against xylan, laminaran and lichenan were observed. Amylase, maltase and cellobiase activities were also observed in bacterial strains isolated and cultured from isopod midgut, and may account for the measured whole-animal activities. In an artificial temperature gradient, M. graniger selected temperature 3.5 ± 5.4 °C with lower and upper extremes of –1.5 and 18.5 °C. Respiration, as measured by VO₂, was almost independent of temperature between 5 and 10 °C, then increased between 10 and 30 °C. These ecophysiological measures are consistent with adaptation to a stenothermal environment.     

Rose (<Emphasis Type="Italic">Rosa</Emphasis> spp.) Germplasm Resources of Turkey

Turkey is one of the most important Rose germplasm centers. About 25% of all rose species are native to Turkey. Flowers of some rose species, such as Rosa gallica and Rosa damascena, have been used for rose oil and rose water production in Anatolia for a long time. Fruits (rose hip) of some other species have economic value and are also used for medicinal purposes. In this paper, Rosa species found in Turkey are listed, their distribution within the provinces is listed, as well as their characteristics and uses.     

Patterns of diversity in pigeonpea (<Emphasis Type="Italic">Cajanus cajan</Emphasis> (L.) Millsp.) germplasm collected from different elevations in Kenya

Pigeonpea germplasm accessions collected from low (<500 m), medium (501–1000 m), high (1001–1500 m) and very high elevation zones (>1500 m) of Kenya were evaluated for 15 agronomic traits and seed protein content at ICRISAT, Patancheru, India. There were significant differences (P < 0.001) among elevation zones for the number of primary and secondary branches, days to 75% maturity, pod length, seeds per pod, 100-seed weight and seed yield. Mean values indicated that the accessions from low elevation zone were significantly different from those collected in higher elevation zones for early flowering and maturity, number of primary branches, pod length, number of pods per plant, seeds per pod, 100-seed weight, seed yield and harvest index. None of the accessions collected in Kenya belonged to extra early (<80 days to 50% flowering) and early (80–100 days to 50% flowering) maturity groups, as defined by time to flowering at Patancheru, India. Mean diversity index based on all characters indicated that accessions from the low elevation zone are more diverse than those from the higher elevation zones. Frequency distribution for trait extremes indicated that the accessions from the low elevation zone were early to flower and mature, short statured, produced more primary and secondary branches with high pod bearing length, long pods, more pods per plant, more seeds per pod, a high seed yield and harvest index. Accessions from the very high elevation zone were late flowering, with a large number of tertiary branches, large seeds and a high shelling percentage and could be a source for cold tolerance and the breeding of vegetable types. Results suggest that the elevation of collection sites is therefore a very important determinant of variation patterns of pigeonpea in Kenya.