Neue und interessante Arten aus dem Miozän von Salzhausen im Vogelsberg

The investigations of the Salzhausen (Vogelsberg/Western Germany) brown coal materials held in some museums have shown new and interesting species which complete the picture of an autochthonous Mastixioidea-flora from the middle Miocene age. Fruits and seeds of the families Ulnaceae, Moraceae, Betulaceae, Actinidiaceae, Tiliaceae, Rosaceae, Lythraceae, Cornaceae, Nyssaceae, Mastixiaceae, Rhamnaceae, Vitaceae, and Araceae have been described. New species are Gironniera verrucata Mai, Morus germanica Mai, Swida discimontana Mai, Ziziphus striata (Ludwig) Mai et Gregor, Ampelopsis malvaeformis (Schlotheim) Mai, Parthenocissus langsdorfii Mai, Epipremnum avimontanum Gregor, and E. salzhausense Gregor. A revised register of the fossil flora contains about 60 species positively idenitfied. Particular ecological conditions the “carpolithes coal”-formation with its accumulation of fruits and seeds have brought into effect, whereas the dysodil-like brown coal is discernable as a stillwater formation.     

Kritische Revision der „Thlaspi”︁-Arten Europas,Afrikas und Vorderasiens I. Geschichte,Morphologie und Chorologie

In the general introduction of a taxonomical revision of the genus Thlaspi L. from Europa, the Near East and Africa — a conspectus of the species till now comprised within this genus has already been published — a historical survey of the genus Thlaspi is given. Morphological resp. anatomical characters have been judged. The structure of the seedtesta inter alia exhibited a different pattern which proved to be valuable for differentiation. In Thlaspi s. str. this pattern revealed to be well distinguishable from all the other Thlaspi-species hitherto put in this genus; thus showing Thlaspi s. str. a species-complex of its own. The characteristical differences of the numerous species out of the Thlaspi s. str.-complex allow further separation of different genera, so that the hitherto existing genus Thlaspi has been found to be a mosaic of different genera. The degree of their closer or wider relationship, however, could be investigated after extensive studies in different genera of the Brassicaceae (Cruciferae). A subordination of these complexes of closer relationship as subgenera of the genus Thlaspi is impossible, because the morphological and anatomical differences are too great. A persistency in the hitherto scope of a heterogenous genus Thlaspi is considered unreasonable and would encourage a greater humping of many genera within the family Brassicaceae which are well separated till now. This would not reflect the natural conditions. Additional figures of fruits and seedtestas of different species support this view. Finally the geographical distribution of the several genera has been described which in Noccaea Moench shows shortly the wide extension of this genus throughout northern Asia and the extratropical America.     

Piceoxylon pseudotsugae GOTHAN emend. VAN DER BURGH aus dem Obermiozän von Ottendorf‐Okrilla bei Dresden,Deutschland

Piceoxylon pseudotsugae Gothan emend. Van der Burgh from the Upper Miocene from Ottendorf‐Okrilla near Dresden, Germany. A fossil wood, collected in Ottendorf‐Okrilla by H. Kubasch, Kamenz, is described in this paper. It is identified by the first author as Piceoxylon pseudotsugae Gothan 1906 emend, van der Burgh 1973 because of its clear spiral thickenings in the tracheids (early and late wood) together with vertical and horizontal resin ducts. Tertiary wood assigned to this species is up till now only known from a few localities in North America and Europe (Rheinland/Germany, Austria, Silesia/Poland). The recent comparable species, Pseudotsuga menziesii (Mirb.) Franco, is known from a wide variety of localities in North America, with a very variable range concerning temperature. It is a tree of well drained, slightly acidic soils, preferably on sedimentary rocks with a volcanic or glacial origin. In the Tertiary of Europe this tree is also known from brown coal deposits. Therefore, for the Tertiary species a habitat in swamp environment must be added.     

河滨湿地不同植物群落根系分布特征与土壤理化性状的关系——以黄河中游荥阳段为例

在黄河中游郑州荥阳段,选择了5种河滨湿地植物群落进行根系和土壤性状特征研究,以期阐明不同植物群落的根系分布规律与土壤性状的关系,为河滨湿地植物群落组成以及土壤质量恢复提供科学参考。结果表明(1)在0—40 cm土层,根生物量密度与根长密度的平均值均表现为：芦苇群落(Phragmites australis)和芦苇-狗牙根(Cynodon dactylon)群落均大于芦苇-拂子茅(Calamagrostis epigeios)-狗牙根群落、拂子茅-狗牙根群落、拂子茅-狗牙根-水莎草(Juncellus serotinus)群落。拂子茅-狗牙根、芦苇-拂子茅-狗牙根、拂子茅-水莎草-狗牙根三种植物群落类型下根生物量密度、根长密度在0—20 cm表层土壤较大,芦苇群落和芦苇-狗牙根群落的根生物量密度、根长密度在10—40 cm的土层较大。(2)黄河河滨湿地芦苇群落、芦苇-狗牙根群落的土壤以粉粒为主,拂子茅-狗牙根群落、芦苇-拂子茅-狗牙根群落、拂子茅-狗牙根-水莎草群落的土壤主要以砂粒为主。在0—40 cm土层,芦苇群落、芦苇-狗牙根群落的土壤含水率、土壤有机质、有效氮和有效磷含量均显著高于...     

Diskriminierung von Kohlenstoff- und Wasserstoffisotopen: Zusammenhänge mit dem Photosynthesemechanismus und den Standortbedingungen

• 1 Bei einer C₃- (Pisum sativum), einer C₄- (Zea mays) und einer CAM-Pflanze (Bryophyllum daigremontianum) wurde nach Anzucht unter gleichen Bedingungen der δ¹³C- und der δD-Wert in verschiedenen chemischen Fraktionen untersucht. Dabei ergab sich:

• a) Beim D-Gehalt der organischen Trockensubstanz zeigte sich eine klare Reihung: δD CAM <> δD C₄ > δD C₃.
• b) Die Wurzeln aller drei Pflanzenarten enthalten in der organischen Trockensubstanz relativ mehr ¹³C und D als die Sprosse.
• c) Hinsichtlich des ¹³C-Gehaltes ist bei den untersuchten Arten jeweils die Lipidfraktion verarmt (besonders beim lipidarmen Bryophyllum), die wasserlösliche Fraktion dagegen angereichert (wieder besonders stark bei Bryophyllum). Die Werte für Cellulosenitrat stimmen in jedem Falle weitgehend mit denen für die gesamte organische Fraktion überein.
• d) Der δD-Wert ist bei der Lipidfraktion aller Arten weit negativer als der der gesamten organischen Trockensubstanz; am relativ geringsten ist die Differenz bei der CAM-Art. Auch die Proteinfraktion von Pisum und Zea (bei Bryophyllum nicht analysiert) ist deuteriumärmer als die organische Trockensubstanz, die wasserlösliche Fraktion dagegen reicher. Der δD-Wert des Cellulosenitrats stimmt wieder gut mit dem der organischen Trockensubstanz überein. Bei diesen Werten wurde der Isotopenaustausch während der Präparation berücksichtigt.

• 2 Es wurden Hinweise dafür gegeben, daß die verschiedene Diskriminierung des ¹³CO₂ bei der Photosynthese der Land- und Wasserpflanzen vorwiegend auf die Verwendung von freiem CO₂ einerseits bzw. von HCO₃-andererseits (oder von einem Gemisch beider Verbindungen) zurückgeht. Der δ¹³C-Wert kann daher (in Verbindung mit anderen Methoden) dazu benutzt werden, die Art der CO₂-Quelle submerser Wasserpflanzen zu bestimmen. Außerdem kann mit seiner Hilfe die Verwertung von freiem CO₂ oder HCO₃^– bei der CO₂-Fixierung von photolithotrophen oder chemolithotrophen Bakterien mit bisher unbekanntem Fixierungsmechanismus festgestellt werden.
• 3 Pflanzenarten mit potentieller Fähigkeit zur nächtlichen CO₂-Fixierung wurden durch die Außenbedingungen, speziell die Dürrebelastung, verschieden stark in ihrer aktuellen Dunkelfixierung beeinflußt: Es gibt Arten (z.B. die untersuchten mexikanischen Crassulaceen), die auch bei relativ guter Wasserversorgung starr am CAM festhalten, und andere (z.B die heimischen Sedum-Arten), die erst unter Bedingungen, die im Labor, nicht aber an ihren natürlichen Standorten verwirklicht werden können, zum CAM übergehen.
• 4 Der Deuteriumgehalt des Gewebswassers und als Folge davon der organischen Trockensubstanz läßt sich in Verbindung bringen mit der Transpirationsrate und damit auch der Verweildauer des Wassers in einer Pflanze. Wasserpflanzen, speziell marine Algen, sind deshalb in ihrer organischen Trockensubstanz gegenüber dem Medium besonders an Deuterium verarmt, CAM-Pflanzen dagegen besonders deuteriumreich; bei letzteren kann der δD-Wert daher in Verbindung mit dem δ¹³C-Wert dazu benutzt werden, CAM-Pflanzen an trockenen Standorten von C₄-Pflanzen zu unterscheiden.
• 5 Mit Hilfe des δ¹³C- und δD-Wertes lassen sich nicht nur neue Taxa von C₄- und CAM-Arten ermitteln, sondern auch ihr Anteil an der Flora klimatisch definierter Gebiete. Es zeigte sich u.a., daß alle untersuchten Gräser der Indischen, Ägyptisch-Arabischen und SW-Afrikanischen Wüste C₄-Arten sind, während z. B. unter den mitteleuropäischen Euphorbien nur zwei eingeschleppte Arten nicht dem C₃- (sondern dem C₄-) Typ angehören.

     

Einige für die bulgarische Flora neue und seltene Arten

The author reports new for the science and new and rare plants species for the Bulgarian Flora. The new species for the science are Ranunculus stojanovii sp. nov. and Ophioglossum vulgatum L. var. ovatum var. nov. R. stojanovii grow wild near Ravnogor village, Pazardžik district (Rhodopi mountain at 1200 m.s.l.). O. vulgatum L. var. ovatum is collected in the meadows at Banja village near by Karlovo town, Plovdiv district. The new species for the Bulgarian Flora are Erythronium dens-canis L. ssp. niveum (Baumg.) Buia et Paun, collected at Radovci village, Tarnovo district, and Parentucellia latifolia L. f. albiflora (Raul) Hall, collected at Banja village, Plovdiv district. The remaining 21 species are rare for the Bulgarian Flora. New localities are indicated for them.     

Neutrale Mutationen und evolutionäre Fortentwicklung

Neutral mutation and evolutionary progress The process and causes of regressive evolution are still under debate. Contrary to DARWIN'S original assumption, Neo-Darwinian proponents make selection responsible for reduction. Biologically functionless structures like eye and pigmentation in cave animals deliver excellent material to study this problem. Comparison of regressive (eye, pigmentation, aggression, dorsal light reaction) and constructive traits (gustatory equipment, egg yolk content, feeding behavior) in epigean and cave fish (Astyanax fasciatus, Characidae) reveal a high variability of the regressive features in the cave forms. Contrary to this, the constructive traits are characterized by a low variability in epigean and cave fish. This difference is attributed to the lack of selection on regressive structures. The existence of an intermediate cave population between epigean and true cave fish of A. fasciatus makes possible the study of evolutionary rates. It is shown that the regressive traits do not evolve more quickly than the constructive ones do. On the contrary, constructive traits like egg yolk content are even more rapid because they are of great biological value in the cave biotope. Especially energy economy is claimed by Neo-Darwinists to play a decisive role as a selective force. Comparison of the development of epi- and hypogean larvae of A. fasciatus shows that the formation of a smaller and less differentiated eye in the cave specimens has no effect on body growth. Furthermore, even behavioral traits like aggressiveness, schooling, dorsal light reaction, or negative phototaxis, which all are not performed in darkness by the epigean ancestor, become genetically reduced in the cave fish. The principles of regressive evolution, loss of selection and increase in variability, play a central role in evolution in general. When biota with empty niches are colonized, stabilizing selection relaxes from the special adaptations to the niche inhabited before by the invading species. Variability may arise in these and is permitted as long as fitness is guaranteed. Such processes characterize adaptive radiation. Examples are given by the species flocks on isolated islands or in chemically abnormal lakes like those of the East African Rift Valley. Only secondarily, on the basis of the arisen variability, does directional selection promote the newly developing species into different niches. The loss of stabilizing selection is an important factor for the evolutionary process to be open for evolutionary progress.     

Introgressive Hybridisation,Sippenbildung und Vegetationsänderung

Introgressive hybridization is a phenomenon, which takes place in natural conditions, on vast territories, during thousands of years and connected with paleogeographic events. The introgressive hybridization usually involves not only certain pairs of species in a definite region, but many species. Species, pertaining to different specific rows or different sections of genus enter into the introgression. Hybrid forms, having arisen in the process of introgression are of low stability. Change of climatic conditions leads to absorption of hybrid by those ancester-parents, for which this change is most favourable. The absorption by one species edificator of his own hybrid populations reflects the displacement of one vicaring formation by another. The introgressive hybridization, which has been occuring during the tertiary time and has lead to speciation nowadays presented in classification by sectional level (Picea sect. Omorika, Larix sect. Multiseriales), has not created new stable lines of development. Introgressive hybridization in cases known, as well as in examples of Picea and Larix has not opened and is not opening new evolutional perspectives.     

Soil nutrient heterogeneity and competitive ability of three grass species (<Emphasis Type="Italic">Festuca ovina,Arrhenatherum elatius</Emphasis> and <Emphasis Type="Italic">Calamagrostis epigejos</Emphasis>) in experimental conditions

We studied the effects of differences in root growth and nutrient pool on the competitive ability of Festuca ovina (short grass), Arrhenatherum elatius and Calamagrostis epigejos (tall grasses) grown in monocultures and in mixtures of homogeneous and heterogeneous environments during two growing seasons. Analysis of variance revealed a significant effect of plant species on nutrient concentrations in above-ground biomass and of substrate type on contents of N, K, Ca, Mg in biomass. The ANOVA also confirmed the significant effect of competitive environment on the concentration of N, K in above-ground biomass. In heterogeneous environments, both tall grasses (in competition with F. ovina) were able to produce more roots in the nutrient-rich patches and to accumulate more nitrogen in plant tissues, which was associated with higher yield of their above-ground biomass. Thus, the relative competitive ability for nutrients of both tall grasses was higher than that of F. ovina. This competitive ability of A. elatius to C. epigejos increased in heterogeneous treatments.     

A taxonomic study of theCalamagrostis tashiroi group (Poaceae)

TheCalamagrostis tashiroi group was taxonomically revised by examination of population samples from four areas and herbarium specimens. Results of the morphological examination, coupled with observations of the habitats, showed that three taxa with distinct morphological features and definite geographical ranges can be recognized in this group. They were disposed asCalamagrostis tashiroi subsp.tashiroi, C. tashiroi subsp.sikokiana, stat. nov. andC. onibitoana, sp. nov.     

Growth responses of arctic graminoids following grazing by captive lesser snow geese

The effects of grazing by captive goslings of the Lesser Snow Goose on coastal vegetation at La Pérouse By. Manitoba were investigated. Swards of Carex subspathacea, Festuca rubra and Calamagrostis deschampsioides were grazed once for different periods (0–180 min) and regrowth of vegetation determined, based on measurements of standing crop, net above-ground primary production (NAPP) and forage quality (leaf nitrogen content). The amounts of foliage removed from swards of Carex subspathacea increased with the length of the grazing period, but after 44 days of regrowth there were no significant differences in above-ground biomass between control and grazed plots. While the amount of foliage removed by goslings from swards of Festuca rubra increased with the length of the grazing period (except after 150 min of grazing), the increase in biomass following defoliation was similar among treatments. Goslings removed little biomass from swards of Calamagrostis deschampsioides, even when the opportunity for grazing was 180 min. No significant differences in standing-crop or NAPP between grazed and ungrazed plots were detected by the end of summer. Grazing had no significant effect on amounts of nitrogen in leaf tissue of all species, suggesting that faecal nitrogen was not rapidly incorporated into plant biomass within the growing season. Patterns of regrowth of these species are compared to that of Puccinellia phryganodes. An increase in goose numbers in recent years has led to birds foraging on less preferred species, such as Calamagrostis deschampsiodes and Festuca rubra. Their poor nutritional quality and a lack of a rapid growth response following defoliation may explain, in part, the decline in the weight of wild goslings recorded over the last decade.     

Revision der fossilen Leguminosengattung Podogonium HEER (= Gleditsia Linné) aus dem europäischen Jungtertiär

The genus Podogonium HEER (extinct legume), known from many Tertiary localities in whole Europe, is rivised and newly combined: Gleditsia knorrii (HEER) GREGOR concerns the fructifications, Gleditsia lyelliana (HEER) HANTKE the leaves; the latter is divided into two formas: knorrii and lyelliana. A comparison with two one-seeded recent Gleditsia-species (G. aquatica MARSH. — USA and G. heterophylla BUNGE — China) yields following palecological setting for the fossil species: They lived under wet conditions (swamps, river banks, alluvial soils) — not in dry climate as believed formerly, together with deciduous trees. The stratigraphical range is from Lower Miocene to Pliocene, with the main occurence in Middle Miocene times (Upper Helvetian, Tortonian, Sarmatian-Karpatian, Badenian, Sarmatian). The fossil species are important plants in the Upper Freshwater Molasse in Bavaria and the adjacent regions.     

Vergleich von Messungen des kLa-Wertes nach der stationären und der dynamischen Methode bei der Fermentation von L-Lysin und Turimycin

The calculation and scale-up of fermentation processes need k_La as one of the most important engineering data. There are two methods to determine k_La depending on power input, aeration rate and the properties of the fermentation broth: static with a balance between air supply and exit, dynamic gassing out with following the changes of dissolved oxygen concentration during periods of air off and a following air on. Within early intervals of fermentation time the data from both methods agree well, while for later time intervals the dynamic method always gives much lower values for k_La than static. The only explanations for this phenomenon are quick changes in the oxygen metabolism or an enzymatic storage of oxygen. For both gassing out and saturation period it is possible to calculate the same absolute amounts of this additional oxygen.     

Variabilität, Verbreitung und Systematik der Arten und Unterarten in der Gattung Pungitius Coste, 1848 (Pisces, Gasterosteidae)

On the systematics and the evolution of variation and distributional patterns in the species and subspecies of the genus Pungitius Coste, 1848 (Pisces, Gasterosteidae) 1. In the genus Pungitius (similarly as in Gasterosteus) there seems to be of some interest the bony armature, especially from the zoogeographical point of view. These lateral bony shields are developed in the skin (instead of scales which are completely lacking in the family of Gasterosteidae) and are more or less present just as to the provenance of the individuals. 2. Preponderantly with respect to this bony armature several species and subspecies have been distinguished in the genus Pungitius, the variability, distribution and systematics of which are critically reviewed and compared in the present paper on the basis of museum material and data from the literature. 3. For the sake of adequate interpretation of modern distributional patterns there may be assumed an originally fully armoured type at the end of the Tertiary from which (after having escaped the ice by southward migration) during the Pleistocene period in several refugial areas new species or subspecies have derived, partially by reduction of the bony armature under freshwater conditions. During postglacial times these subspecies penetrated different areas but in some localities also produced mixed populations ofter having contacted within the same region. At least in some cases this may have led to subsequent hybridization. 4. The species P. platygaster in its modern distribution in the ponto-caspi-aralic region is now geographically isolated from the holarctic-circumpolarly distributed P. pungitius in its recent subspecies pungitius with reduced bony armature. Of this latter (originally fully armoured) species populations are assumed to have penetrated, at latest during the penultimate (= Riß) glaciation the Caspian Sea and subsequently the Black Sea and Lake Aral. These populations are the assumed ancestors of the nowaday still fully armoured P. platygaster. A decision as to the real degree of differentiation between the recent P. pungitius and P. platygaster has to be left to future crossbreeding experiments the results of which will possibly lead to a subspecies concept only. 5. In contrast to the foregoing the fully plated original type of P. pungitius underwent a serious reduction in its bony armature especially in the Southwest European refugium which led to a total loss of bony shields in the subspecies P. p. laevis. 6. As may be concluded from the now occurring types, this reduction seems to have been generally less pronounced in the East Asiatic refugium. We are confronted here, probably as a result of postglacial spread with the occurrence of three subspecies within the same area, i. e. the fullyarmoured P. p. sinensis on the one hand, and P. p. tymensis with reduced lateral plates (and also reduced lateral processes of the pubic bones in the pelvis girdle) and the holarctic-circumpolarly distributed P. p. pungitius with likewise reduced bony armature on the other hand. Of these subspecies the fully plated sinensis seems in its appearance to approach best what we perhaps may imagine as the original type of P. pungitius at the end of the Tertiary.     

Beiträge zur Pollenmorphologie und Systematik der Convolvulaceen-Gattungen Maripa und Mouroucoa

Suggested by a previous communication on the occurence of two types of apertures among the pollen grains of Maripa s. l. (Convolvulaceae), 16 species of this genus were investigated palynologically. 3-zonocolpare grains mixed with 4–6-pantocolpate and 6–15-pantocolpate grains were found. The structure of the exine (infratectale bacula with or without supratectale processes) reveals further differences. The combination of these characters in the genus Maripa offers the separation into four types of pollen grains. The genus Mouroucoa is represented by its own type. These facts stress the necessity of the generical separation of the two genera. Consideration of pollen morphology yields some new aspects for subdivision of the genus Maripa.     

Modeling of α(1–4) chain arrangements in α(1–4)(1–6) glucans: The action and outcome of β-amylase and Pseudomonas stutzeri amylase on an α(1–4)(1–6) glucan model

Simulated enzymic debranching of a β-limit dextrin model, prepared from a computed construct made by random extension and branching, and given the CCL value of w-maize amylopectin (and equal amounts of external chains with ECL values of 2 and 3) has been related to experimental chromatograms of the debranched β-limit dextrin of the amylopectin. The profile was similar to those from gel chromatograms and IEC-PAD chromatography.The equivalent lengths in glucosyl units of grid-links (g-links) of internal and external chains in constructs were calculated from the ICL and ECL values of amylopectin and models produced from the constructs with the appropriate lengths for internal and external chains. These derived models were subjected to simulated hydrolysis by Pseudomonas stutzeri amylase and the products compared with those of the experimental distribution from w-maize amylopectin. With the model the amounts of maltotetraose and maltodextrins released were similar to the experimental values but the distribution of branched maltodextrins was quite different. Unlike w-maize amylopectin – a polymer with the cluster structure – which has given a profile of molecular sizes of maltodextrins with low amounts of single and small numbers of internal chains and with a peak at a M_W of about 14,000 (13 chains), in the model the proportion of maltodextrin with one internal chain was high and as d.p. increased the amounts decreased exponentially. This would be expected if the distribution of internal chains in the core was random. It is suggested that in the core of a model prepared from a construct made with alternating probabilities of extension – one in which this probability is high relative to branching, and a second in which it is low – may give clusters of branched maltodextrins with short internal chains which are joined by longer chains; more closely approximating the distribution of internal chains of different lengths in amylopectin.An arrangement for amylopectin molecules in the starch granule has been proposed. In this, they have a wafer-like, discoidal shape, composed of the amorphous zone overlain with the double helical, crystalline region. The flat macromolecules are concentrically layered with the former on the inside and the latter oriented to the outside of the granule.     

Vesicular mycorrhizal colonization of seedlings of Pinaceae and Betulaceae after spore inoculation with Glomus intraradices

 Although Pinaceae and Betulaceae have been reported to contain Glomus–type root endophytes, its ecological importance and the conditions influencing this symbiosis are poorly understood. Seedlings of Abies lasiocarpa, Alnus rubra, Pinus contorta, Pinus ponderosa, Pseudotsuga menziesii, and Tsuga heterophylla were inoculated with Glomus intraradices to determine the vesicular-arbuscular mycorrhizae (VAM) development and responsiveness of these hosts. The role of companion VAM host plants on mycorrhizal colonization and nutrient uptake by Pseudotsuga menziesii was also examined by growing seedlings of Pseudotsuga menziesii in dual culture with VAM hosts Thuja plicata or Calamagrostis rubescens. After 8 weeks, no seedlings were colonized. At 16 weeks, 8 of 17 Thuja plicata seedlings grown with Pseudotsuga menziesii and all 18 inoculated Thuja plicata seedlings grown alone were colonized with vesicles and hyphae. Two of 17 inoculated Pseudotsuga menziesii seedlings grown in dual culture with Thuja plicata were colonized with abundant vesicles and hyphae. No ectomycorrhizal seedlings grown in monoculture were colonized. At 9 months, all 10 Calamagrostis rubescens and all 10 inoculated Pseudotsuga menziesii seedlings grown in dual culture were colonized by vesicles and hyphae. Two of 10 inoculated Pseudotsuga menziesiiand 1 of 10 inoculated Pinus ponderosa seedlings grown in monoculture were similarly colonized. The mean phosphorus content in the needles of colonized Pseudotsuga menziesii seedlings grown with Calamagrostis rubescens was about twice as high as in noncolonized Pseudotsuga menziesiiseedlings grown with Calamagrostis rubescens. Tissue nitrogen did not differ between these treatments. The results show that Glomus intraradices colonization of Pinaceae is most successful when a VAM host is present, although some vesicular colonization of Pinaceae occurred in the absence of a VAM host. Accepted: 24 September 1997     

Beiträge zur Ökologie der benthischen Algen des Hochgebirges in den Pyrenäen II. Cyanophyceen und übrige Algengruppen

Little research has been made on the litoral algal flora of unpolluted high mountain lakes and streams. Since the algal flora is often used to estimate the water quality, it is of great value to know more about the ecology of benthic forms living under extreme oligotrophic conditions. An investigation was made of the benthic and littoral microphytic vegetation of Esteragne torrent, and Lac de Port-Bielh in the High Pyrenees. Both waters combine a low calcium content with a consistently basic pH. A comparison of their flora with that of other lakes may help to deal with the problem of whether the algal flora is determined more by the calcium content or the pH. The algal flora of Esteragne torrent differs little from that of low-calcium streams of the central European highlands. In Lac de Porth-Bielh there is a distinct depth-zonation among the dominant algae. The dominant taxa at a depth of 0–0,5 metres are: Schizothrix lacustris f. lutescens, Sch. calcicola, Gloeocapsa tornensis, Pleurocapsa minor with Cyanostylon microcystoides and Hydrococcus cesatii particularly on the undersides of the stones; from 0,5 to 1,5 m: a massive growth of Nostoc zetterstedtii; from 2,5 to 4,5 m: Schizothrix funalis; from 7 m: Nitella flexilis. In addition the lake includes a number of rare and little known forms such as? Onkonema sp., of. Desmosiphon maculans, Lyngbya lachneri, Homeothrix sinensis, Chantransia chalybea v. profunda, Siphononema polonicum status chamaesiphonoides. Green algae were almost completely absent from the upper zones, in contrast to the usual findings. The littoral flora has a very distinctive character, and is not directly comparable with that usually found in lakes with either high or low calcium content. A certain resemblance to lakes with a high calcium content can be found only if all the forms present particularly with lower abundances are considered. The very strong development of lithophytes should be emphasized in contrast to their usually low density in lakes with low calcium content. The systematic section deals with systematic and taxonomic problems in a number of difficult forms.     

Enzymatische Hydrolyse und Ethanolgärung von Lignocellulosen

The kinetics of enzymatic hydrolysis of different lignocellulosic materials (wheat straw, newspaper and microcrystalline cellulose Avicel PH 101) was studied using the cellulase complexes from Trichoderma reesei QM 9414 and its mutants M 5, M 6, MHC 15 and MHC 22. The maximum yields of hydrolysis were obtained with wheat straw partially delignified with 1% NaOH as substrate, and using the enzyme from the mutants T. reesei M 6 and MHC 22. The possibility of simultaneous enzymatic hydrolysis and ethanol fermentation of wheat straw using the enzyme complex from M 6 and yeasts of the genus Candida and Torulopsis was also investigated. A good conversion of liberated glucose and cellobiose to ethanol was obtained, however, xylose was not fermented.