Cryptic hybrids between Pinus uncinata and P. sylvestris

We tested the performance of molecular markers and biometric traits in the identification of hybrids between closely related mountain pine (Pinus uncinata) and Scots pine (Pinus sylvestris). A plastid DNA marker and a set of morphological and anatomical needle traits were applied in analyses of individuals from several sympatric stands of the species and a single‐species' population from southern Europe, used as a reference. A polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) marker from the plastid trnL–trnF region and morphological and anatomical traits clearly discriminated between the pure species. Significant differences were found between P. uncinata and P. sylvestris, mostly in the shape of epidermal cells and the number of stomata. Four putative hybrids with P. sylvestris morphology, but with P. uncinata plastid DNA haplotypes, were found in a population from Sierra de Gúdar near Valdelinares, the southernmost locality of the latter species in eastern Spain. Discrimination analyses between and within populations placed these individuals on the edge of an agglomeration of P. sylvestris individuals. The results suggest that hybridization between the species is rare, but can result in cryptic hybrids morphologically similar to the maternal species. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 473–485.     

Effects of Concentration and Time of Exposure on the Phytotoxicity of Linuron

When seedlings of lettuce and turnip were grown in nutrientsolutions containing different concentrations of linuron, theconcentration in the shoot at the time when toxicity symptomsappeared was related to the solution concentration. With lettuce,for example, symptoms were recorded after 7 d at 0.15 µg/mland the shoot concentration was 2.7 µg/g fresh wt. At0.06 µg/ml, symptoms appeared after 10 d and the shootconcentration was then 1.1 µg/g fresh wt. If grown fordifferent periods in solutions containing linuron and then transferredto fresh nutrient solutions containing no herbicide, turnipor lettuce seedlings which had accumulated 0.7–0.8 µglinuron/g fresh wt developed toxicity symptoms 4 to 6 d later.Seedlings were also treated with linuron after they had grownfor different periods in control nutrient solutions. The shootconcentrations attained before toxicity symptoms appeared werehigher in those seedlings which were larger when herbicide treatmentbegan. These results show that the herbicide concentration insolution, time of exposure, and age of seedling are interrelatedin determining linuron phytotoxicity.     

Bryozoans as substratum of fossil fistulose Foraminifera (Fam. Polymorphinidae)

In the Upper Cretaceous-Lower Tertiary sections exposed in the Curfs quarries at Berg (munic. Berg en Terblijt - also known as Geulhem, southern Netherlands) and some other localities, numerous foraminifers of the family Polymorphinidae with complete fistulose apertures have been found. These apertures, which are equipped with circular openings and auxiliary apertural chambers, branching and numerous narrow projecting tubes or stolons, have been widely reported, but their role has been the subject of controversy. The Dutch material shows the foraminifers attached with the apertural tubes to fragments of bryozoan colonies or molluscan shells, suggesting that the tubes could perhaps act as holdfast organs. Most specimens were found in calcarenites of the nearshore facies. The foraminifers cannot be treated as symbiotic organisms nor parasites but as epifauna in search of protection from mechanical destruction by waves and current action. The present case may be best explained as an adaptation of sessile foraminifers with fragile hyaline tests to live in highly disadvantageous, high-energy conditions.     

The Inhibitory Effect of (2-Chloroethyl)-trimethylammonium Chloride on Chlorophyll and Protein Synthesis in Lettuce Cotyledons, and its Reversal by Potassium

Germinated seeds of Lactuca sativa (L.) were placed in Petri-dishesin (2-chloroethyl)-trimethyl-ammonium chloride (CCC; 0.005–0.05M), KN0₃ (0.01 M), and KC1 (0.01 M) solutions, and incubatedfor 2 or 5 days under continuous light. CCC strikingly arrestedchlorophyll accumulation, and retarded cotyledon growth relativelylittle. The retardant inhibited ¹⁴C-leucine incorporation intobulk proteins of the cotyledons. KN0₃ and KC1 promoted cotyledongrowth and chlorophyll synthesis per cotyledon by about 150per cent, and about doubled protein synthesis. Potassium saltscompletely reversed the inhibitory effects of CCC on chlorophylland protein synthesis. It is suggested that the inhibition ofgreening by CCC is dependent on a prior inhibition of proteinsynthesis.     

Application of Affinity Adsorption Chromatography for the Purification of Human Brain Specific Antibodies

WE have found a glycoprotein in the human brain which is brain specific on immunological criteria¹. Ontogenetically, this glycoprotein appears at the stage of premyelination glia. The amount increases in parallel with the development of the human brain and probably remains at a constant level in the adult brain². We found it in normal and pathological human brain, predominantly in the white matter and in trace quantities in the grey matter (putamen, n. caudatus)². It is not present in the peripheral nerves, but was found in the n. opticus. This component is almost identical with the brain specific protein of Macacus rhesus and semi-identical with the brain-specific protein of rats².     

Regulation of Ciliary Pattern in Ciliates*

SYNOPSIS. The modes of pattern regulation found in the ciliates Dileptus and Paraurostyla are compared. These forms are systematically distant but both possess very extensive regenerative capacities. They are characterized by 2 types of ciliary patterns: the ciliature of Dileptus has largely a simple pattern composed of single kinetosomes while that of Paraurostyla has a complex pattern composed of aggregates of kinetosomes interconnected by amorphic matter. In both ciliates a change in cell size evokes pattern regulation which differs substantially in the extent of pattern replacement, timing, and localization of morphogenetic activities. It is concluded that these differences result from the pattern constituents.     

Restoration ecology research above the timberline: colonization of safety islands on a machine-graded alpine ski run

Colonization was studied in safety islands installed on a machine-graded downhill ski run (ca 2500m asl) and respectively aged 7, 8, and 9 years. For comparison, the neighbouring non-restored plots were investigated. The study included assessment of species richness (alpha diversity), size and spatial structure of the immigrant populations, and the nearest possible diaspore sources. The number of colonizing species recorded in the safety islands totalled 44 whereas only 25 species were found in the non-restored ski run plots close by. The mean species number per whole plot, per 1m2 and per 0.1m2 was significantly higher in the safety islands than in the non-restored ski run plots. Population founders and small populations represented more than half of all immigrant species in the safety islands, but medium-sized and large populations were also present. The overall distribution of plants was patchy but the number of individuals per 1m2 was significantly higher in the safety islands than in the ski run. Travelling distances separating the safety islands from the nearest possible diaspore source were often exceedingly short and ranged between 0.10m and 1m in 47.7% of all populations studied. It seems that the diaspore sources were mostly secondary i.e. plants scattered over the non-restored ski run, and those previously used in restoration trials, served as diaspore donors. The results of the study clearly demonstrate that successful colonization of machine-graded alpine ski runs in the study area is ultimately limited by safe-site availability and not by deficiencies in seed rain or remote diaspore sources. The colonization process in the safety islands is apparently well-advanced. This revised version was published online in August 2006 with corrections to the Cover Date.     

Morphology of Pinus uliginosa (Pinaceae) needles from populations exposed to and isolated from the direct influence of Pinus sylvestris

Eleven needle traits of two contrasting populations of Pinus uliginosa ( P. mugo complex), one located in a Pinus sylvestris forest, the other isolated from the influence of this species, were compared to quantify the degree of hybridization. Statistically significant differences between the studied populations were found, but both of them differed by a similar degree from P. sylvestris . Surprisingly, the P. uliginosa population surrounded by the P. sylvestris forest, which was expected to consist of individuals with intermediate traits, appeared to be more closely related to P. mugo than those isolated from the direct influence of P. sylvestris . Large differences in the distances between the analysed pair of populations of P. uliginosa and P. sylvestris have not influenced the morphological traits of the species. Gene flow from P. sylvestris to P. uliginosa is possible, but is likely to be small and does not differ compared with populations of P. uliginosa . The decline observed during the last three decades in both populations of the species has not influenced their needle morphological traits.  © 2003 The Linnean Society of London , Botanical Journal of the Linnean Society , 2003, 142, 83–91.     

Pinus mugo (Pinaceae) in the Abruzzi Mountains: high morphological variation in isolated populations

Thirty-three individuals of Pinus mugo from the Abruzzian Apennines (Italy), the most isolated population of the species, were examined biometrically to verify the range of trait variation and compared with six other populations sampled in the north-eastern part of the species range. Ten needles and ten cones from each individual were measured and quantified on the basis of 31 traits. The interpopulation comparison revealed a close affinity of the Abruzzian population of P. mugo to three of the six other populations. The other three north-eastern populations, one from the Tatra Mountains and two from the Chornokhora Mountains, appeared to be different. This suggests that these populations originated from other Pleistocene centres of occurrence. The intrapopulation variation of the population from the Abruzzian Apennines is comparable with those of all six populations of P. mugo from the Sudety and Carpathian Mountains. These findings support the hypothesis that isolated but locally abundant plant populations do not necessarily show a reduction in variability resulting from isolation.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 309–316.     

Distribution and feeding of the predatory nematode Anatonchus dolichurus (Mononchoidea) in the Dokka delta (Norway) and its impact on the benthic meiofauna

• 1 A dense population of a large (over 6.5mm long), semiaquatic, predatory nematode Anatonchus dolichurus was found in the delta of the River Dokka, Norway. This is the first time it has been reported in surface fresh waters.
• 2 Nematode distribution was related to water depth, with maximum abundance (over 24000 ind.m^?2) occurring in shallow areas (0.5–2.0m). Sediments at all stations with a high density of A. dolichurus were dry and exposed to air and ice during winter and early spring, and overgrown with macrophytes during summer.
• 3 This predator contributed a greater fraction of total numbers and biomass of the nematode fauna than predatory forms in other known freshwater nematode assemblages. It constituted up to 15.6% of numbers and up to 90% of total nematode biomass.
• 4 Anatonchus dolichurus preyed on Nematoda, small Oligochaeta (mainly Enchyrraeidae) and Chironomidae. It was able to reduce the density of these meiofaunal taxa when present in large numbers in experimental cores.