NOTES ON THE OCCURRENCE OF MALES IN POPULATIONS OF POTAMOPYRGUS JENKINSI

Freshwater prosobranch snails of the genus Potamopyrgus arerenowned for being extremely variable and for reproducing parthenogenetically;in addition they are among the very few animals which appearto have successfully colonized Europe from the Antipodes (seeFretter & Graham, 1978, and Winterbourn, 1972 for reviewsand references). During investigations into the genetics and sex ratios of P.antipodum (or antipodarum) (Gray) in New Zealand, a period ofleave allowed some comparisons to be made with the AustralianP. nigra (Quoy & Gaimard), which is the subject of a separatenote (Wallace, 1978) and the European P. jenkinsi(Smith) discussedhere. (Received 10 March 1978;     

Dry-matter Production and Photosynthesis in Pine Seedlings

Growth analysis and photosynthesis measurements were carriedout on first-year seedlings of Pinus radiata, P. contorta, andP. nigra. P. sylvestris was also included in two growth-analysisexperiments. There appeared to be no difference in relativegrowth-rate (RGR) between the species mentioned, except betweenP. radiata and P. nigra. It was found that when the level ofmineral nutrition was high, P. radiata had a higher RGR thanP. nigra and that the reverse was true at low mineral nutrientlevels. There was no difference in net assimilation rate (NAR)between the species, but NAR appeared to increase and decreasewith mineral nutrient supply. Net photosynthesis per unit of leaf was somewhat higher in P.radiata than in P. contorta; P. nigra had a lower photosyntheticrate than either P. radiata or P. contorta.     

TAXONOMY AND OCCURRENCE OF DENDRODORIS NIGRA AND DENDRODORIS FUMATA (NUDIBRANCHIA: DENDRODORIDIDAE) IN THE INDO-WEST PACIFIC REGION

The nudibranch Dendrodoris nigra (Stimpson, 1855) has hithertobeen considered as a single, highly poly-chromic species. Ourinvestigations of external morphology, anatomy and colour variationhave revealed more than one species exists. This conclusiongives credibility to the previous discovery of differing developmentalpatterns within D. nigra. Besides D. nigra, we recognise Dendrodorisfumata (Rüppell & Leuckart, 1830) which has three distinguishablecolour forms. The occurrence of D. nigra is confirmed to beextensive, however, the species was not found to be circum-Australianas previously reported. The presence of D. fumata in Australiais confirmed and the species is also reported from Hong Kongand Fiji for the first time. The clear separation of these twospecies and recognition of the different colour forms will permita more accurate picture of their distribution. (Received 15 November 1994; accepted 2 January 1997)     

The Effects of Simazine, Applied for Weed Control, on the Mycorrhizal Development of Pinus Seedlings

The herbicide Simazine is widely used in forestry nurseries.Its effect on the incidence of ectomycorrhizae on pine seedlingroot systems was investigated. Under field (nursery) conditions,at routine rates of application, Simazine does not inhibit mycorrhizaldevelopment in Pinus sylvestris and P. nigra, and it may, undersome conditions, actually enhance mycorrhizal formation. Sucha stimulatory effect was also obtained with pot-grown seedlingstreated with the herbicide. It is suggested that soil type andclimatic factors might be involved in determining the responseto Simazine. The mode of stimulation of mycorrhizal developmentby this herbicide is not understood, but it is not via suppressionof weed growth. Pinus sylvestris, Pinus nigra, pine seedlings, ectomycorrhizae, Simazine     

Nutrient Supply, Dry-matter Production and Nutrient Uptake of Forest Tree Seedlings

The dry-matter production and nutrient uptake of forest-treeseedlings grown under controlled levels of nutrition in sub-irrigatedsand culture were investigated. Hardwood seedlings attainedgreater dry weight than conifer seedlings, and Pinus radiataa greater dry weight than P. contorta and P. nigra, but thesegreater dry weights were not related to greater leaf/weightratios, although seed size may have been an important influenceon final seedling dry weight. P. radiata was found to have alower requirement for P than P. contorta and P. nigra in oneexperiment. The demand (total nutrient uptake per unit of time) made bythree species for nutrients upon a site was shown to dependmore upon growth-rate per annum than on efficiency (quantityof nutrients required to produce a unit of dry matter). It isconcluded that the ability of tree species to grow satisfactorilyon soils of low nutrient status depends largely on their abilityfor relatively slow growth. On the other hand, species showinggood response to favourable sites may also make satisfactorygrowth on poor sites.     

Accumulation of Phenolic Compounds in the Necrotic Areas of Austrian and Red Pine Needles Due to Salt Spray

Austrian pine (Pinus nigra) and red pine (P resinosa) were testedfor needle damage caused by salt spray. Morphology and histologyof newly grown needles were compared in 3- and 6-year-old plantsgrowing in the greenhouse under controlled conditions. Pottedplants covered with plastic bags were sprayed daily either withdistilled H₂O or saturated salt solution. Needle tips, mid-partsand bases were fixed after 1, 3 and 24 h, and 3, 7 and 30 din glutaraldehyde+0·1 % caffeine for precipitation ofphenolics. Histochemical reactions and electron microscope observationsshowed that the morphological damage is linked to increasedphenolic compound deposition in mesophyll cells, beginning directlyunder the stomata. Disorganization of membranes leads to deathof the mesophyll cells, even before morphological damage isrecognizable as brown spots on the needle surface. Thus thehistochemical reactions and observations of cell structure revealeddamage earlier than macroscopic observations. Salt injury, phenolic compounds, histological damage, ultrastructural damage, salt spray, Pinus nigra, Austrian pine, Pinus resinosa, red pine     

THE LIMPET PATELLOIDA NIGROSULCATA ON INTERTIDAL PLATFORMS IN THE PERTH AREA, WESTERN AUSTRALIA

Patelloida nigrosulcata on intertidal platforms in the Perthmetropolitan area live on the backs of shells of living abalone,Haliotis roei. Over 95% of abalone 30 mm have one or more limpets,and there is a close relationship between abalone and limpetdensity. Sexes are usually separate in P. nigrosulcata, butabout 4% of the population in hermaphroditic. The animals spawntwice annually in winter (May–June) and spring (October–November).The reproductive periodicity of P. nigrosulata is compared toother published data on acmaeids. ^*Present address: Australian Institute of Marine Science, PMBNo. 3, Townsville, Queensland 4810, Australia (Received 23 March 1987;     

GENETIC VARIATION IN SIX SPECIES OF SACOGLOSSAN OPISTHOBRANCHS

Genetic variation in allozymes of six species of Saco-glossa(Mollusca, Opisthobranchia) from Denmark was studied. Nine enzymesrepresenting 11 loci gave reactions that could be used to calculateallele frequencies. Elysia viridis, Limapontia capitata, L.de-pressa, Ercolania nigra, Alderia modesta and Calliopaea oophagaall showed very great variation both within and between species.Levels of polymorphism varied between 0.5 and 0.8, and levelsof observed heterozygosity were between 0.18 and 0.42. Interspecificidentity of alleles in polymorphic loci was only found betweenthe two species of Limapontia. Even in these two species geneticidentity (I) was very low (0.07) for congeneric species. Theresults are discussed in relation to habitat, fertility, developmenttype and geographic range of the species. (Received 28 February 1990; accepted 26 July 1990)     

Carbonic Anhydrase of a Unicellular Red Alga Porphyridium cruentum R-l. II. Distribution and Role in Photosynthesis

Antibody was raised against Porphyridium carbonic anhydrase(CA) which was electrophoretically recovered from the gel afterSDS-polyacrylamide slab gel electrophoresis (SDS-PAGE) of thepartially purified enzyme. The antiserum reacted with CA ofPorphyridium, but not with that of Chlamydomonas reinhardtii.Even though the antiserum did not react with CA from P. cruentumR-l in Ouchterlony's double immunodiffusion, it blocked theenzyme activity in the presence of 1% Nonidet P-40 and 1% TritonX-100. After Western blotting and enzyme-linked immunostaining(ELIS), only one band which reacted with the antiserum was detectedin the extract of low-CO₂ cells (grown under ordinary air) ofP cruentum, while no significant band was detected in that ofhigh-CO₂ cells (grown under air enriched with 1–5% CO₂).Immunogold electron microscopy of low-CO₂ cells of P. cruentumR-l using this antibody revealed that most of the CA was localizedin the chloroplast, with some in the cytoplasm. No specificbinding of gold particles was observed in the high-CO₂ cells. ¹Present address: National Institute for Basic Biology, Myodaiji,Okazaki 444, Japan (Received May 18, 1987; Accepted September 7, 1987)     

Leaf Abscission and Stem Lesions (Intumescences) on Poplar Clones after SO2 and O3 Fumigation: A Link with Ethylene Release?

Differences in premature leaf abscission and in visible steminjury in genetic lines of poplar followed continuous fumigationswith air pollutant levels of SO₂ (90–100 nl l^–1)and O₃ (70–80 nl l^–1) either separately or together.The clones used were: Populus deltoides var. missiouriensisMarsh., P. nigra cv. ‘italicd’ L., and the hybridsP. nigra cv. ‘italica’ xP. deltoides (He-X/3) andP. nigra cv.‘italica’ x P. nigra cv. ‘Serres’(He-K/7). While most leaf abscission occurred within 20 d fromthe start of fumigation, stem lesions (intumescences), appearedonly after 72 d. Their anatomical characteristics include theformation of lysigenous aerenchyma in the lower parts of theintumescence, the sloughing of superficial cells from the injuredarea, and the development of crystalline formations on the surfaceof the lesions. P. deltoides exhibited the least morphologicalresponse to the gases. Ethylene released from fumigated leaves was determined at thesame gas concentration of SO₂ (100 nl l^–1), O₃ (75 nll^–1) and their mixture. Leaves of P. deltoides consistentlyshowed the lowest ethylene production after the gas treatments.P. ‘italica’ production was higher but was littlealtered by the treatments. The two hybrids He-X/3 and He-K/7showed the greatest increases in ethylene evolution with time.With He-K/7 exposed to the gas mixture the production of ethylenedecreased after the initial sharp rise during days 1–2,and reflected the considerable leaf damage observed after day3. The results suggest that sensitivity to air pollution, (as shownby leaf abscission and the formation of stem intumescences)can be correlated with the level of pollutant-induced ethyleneevolution from leaves. Initially high levels could induce abscission,whilst prolonged production could be responsible for intumescenceinitiation. The discussion proposes a series of events fromSO₂ and/or O₃ entry into the leaf and the physiological reasonsfor the clonal differences. Key words: Sulphur dioxide, ozone, ethylene, poplar, leaf abscission, stem lesions     

Litter Decomposition in Four Woody Species in a Mediterranean Climate: Weight Loss, N and P Dynamics

Decomposition dynamics in leaves and needles of two Mediterraneanshrubs and two pine species growing in the Sierra de Filabres(Almería, Spain) was investigated during 2 years usingthe litter bag technique. The species studied are representativeof the vegetation of the study area and differ greatly in theirfoliar traits. Results are discussed in relation to the initiallitter quality (C, N and P) and through the application of theexponential decay model. The mass lost at the end of study variedin the order: Pinus pinaster < Pinus nigra < Cistus laurifolius< Adenocarpus decorticans. Differences in annual rates ofdecomposition among species are consistent with the particularchemical and structural attributes of their leaves. The massof decomposing litter remaining after 2 years was positivelyassociated with the initial C:N ratio. Weight loss and nutrientrelease were fastest in the leguminous A. decorticans. The resultssuggest the importance of both structure and elemental concentrationof initial litter for decomposition dynamics in Mediterraneanspecies. Copyright 2000 Annals of Botany Company Adenocarpus decorticans Boiss., C:N ratio, Cistus laurifolius L., litter decomposition, litter quality, Mediterranean environments, nutrient dynamics, Pinus pinaster Aiton, Pinus nigra Arnold, single exponential model, Southern Spain     

Comparative Studies of the Seed Proteins of Brassica campestris, Brassica oleracea, and Brassica nigra

The albumin and globulin fractions of the seeds of Brassicacampestris, B. oleracea, and B. nigra have been investigatedusing serological methods and separation by acrylamide gel electrophoresisin order to determine the usefulness of these techniques fortaxonomic studies of the genus Brassica. The results of theprotein analysis given in this paper agree with establishedtaxonomy and suggest that both methods may prove useful in varioustaxonomic problems in the genus Brassica.     

Chloroplast DNA variation in Populus. II. Interspecific restriction fragment polymorphisms and genetic relationships among Populus deltoides,P. nigra,P. maximowiczii,and P. x canadensis

Restriction fragment analysis was conducted to determine interspecific chloroplast DNA (cpDNA) variation and genetic relationships among Populus deltoides, P. nigra, P. x canadensis (P. deltoides x P. nigra), and P. maximowiczii. Total cellular DNAs of these poplars were digested with 16 restriction endonucleases, and Southern blots of the restriction digests were probed with six different cloned cpDNA fragments from Petunia. P. deltoides, P. nigra, and P. maximowiczii each had a distinct chloroplast genome, separated by many restriction-site and restriction-fragment-length mutations, predominantly in the large single-copy region of the genome. P. x canadensis shared the same cpDNA restriction fragment patterns as P. deltoides var. deltoides. P. nigra was most diverged from P. deltoides, and P. deltoides showed close cpDNA relationships to P. maximowiczii. Nucleotide substitutions per site in cpDNA were 0.0036 between P. deltoides and P. maximowiczii, 0.0071 between P. nigra and P. maximowiczii, and 0.0077 between P. deltoides and P. nigra. We suggest that P. nigra should be classified in a new separate section, the Nigrae.     

A COMPARATIVE STUDY OF THE MORPHOLOGY OF THE PULMONATE SNAIL PSEUDOTACHEA LITTURATA (PFEIFFER) AND OTHER SPECIES OF PSEUDOTACHEA, IBERUS AND CEPAEA

A population of Pseudotachea litturata (Pfeiffer, 1851) fromTarifa (Càdiz, Spain) has been studied. The morphologicalresults are compared with those from P. splendida, Iberus gualtierianus,I. alonensis, I. marmoralus, I. guiraoanus and four speciesof the genus Cepaea using, as an exploratory method, the Wagnerparsimony procedure and 18 characters of the shell, genitalsystem and karyotype have been analysed. According to this methodit seems that the taxonomical position of P. litturata in thegenus Pseudotachea is confirmed, and agrees with the phylogeneticalrelationships in this group of species. The genus Cepaea seemsto be well established, although two species groups can be distinguished:C. nemoralis—C. hortensis and C. syluatica—C. vindobonensis.These differ mainly in chromosome number, diverticulum lengthand degree of shell polymorphism. Although the present resultsdo not allow us to clarify the current taxonomical problemswithin the genus Iberus, the species studied seem to belongto a natural group (Received 15 September 1987; accepted 1 January 1988)     

Distribution of Vessel Ends in Stems of some Diffuse- and Ring-porous Trees: The Nodal Regions as 'Safety Zones' of the Water Conducting System

We report measurements of the number of vessels ending withinthe nodes in comparison with that in the internodes Such measurementshave been carried out during autumn 1982 and 1983 in 1-year-oldtwigs of three species with diffuse-porous wood (Vitis vintferaL. Populus deitoides Bartr and Olea europaea L) and three ring-poroustrees (Juglans nigra L, Castanea sativa Mill, Sophora JaponicaL) In all three species with diffuse-porous wood, a significantlyhigher percentage of vessels ending in the nodes (at the leafgap) was recorded when compared with that in the internodesNo significant differences were found between nodes and internodesin this respect in ring-porous trees. Since vessel ends arecapable of screening out gaseous emboli and/or particles biggerthan 1 µm in diameter, we interpret the nodes of diffuse-poroustrees as stem zones providing safety for the water conductingsystem .The reason why ring-porous trees are likely not to needsuch ‘safety zones’ is also discussed Vitis vinifera L, grapevine, Populus deltoides Bartr, poplar, Olea europaea L, olive, Juglans nigra L, Eastern black walnut, Castanea sativa Mill, European chestnut, Sophora japonica L, Japanese pagoda tree, vessel ends, nodes, internodes     

Membrane State and Pollen Viability

The relationship between germinability and fluorochromasia (FCR)has been studied in pollen of eight genera, Secale, Iris, Carex,Eleocharis, Cytisus, Digitalis, Plantago and Lonicera. The FCRtests two properties of the pollen, (a) the integrity of theplasmalemma of the vegetative cell and (b) the presence of anesterase capable of cleaving the fluorogenic ester, fluoresceindiacetate. In general, the correlations between FCR and germinabilitywere found to be very highly significant. This is interpretedas meaning that the primary determinant of pollen viabilityin short-term storage is the state of the vegetative cell membranes.It is suggested that in the partly dehydrated grain at the timeof dispersal the membranes are largely dissociated and do notform an osmotic barrier, but that normal properties are recoveredduring controlled hydration which would normally take placeon the stigma. According to this view, the decay of apparentviability is related to the progressive loss of the capacityof the vegetative cell membranes to regain a normal structureon rehydration. The genera investigated varied in their longevityin storage in low and high humidity conditions. After low-humiditystorage, most showed some enhancement of germination with 1h exposure to a humid atmosphere before transfer to the germinationmedium. During this ‘conditioning’ period the membranesrecover their fluorescein retentivity in step with the increasein germinability. pollen testing, pollen membranes, pollen fluorochromasia, Secale cereale L., Iris pseudacorus L., Carex ovalis Good., Carex nigra (L.) Reichard, Eleocharis palustris (L.) R.Br., Cytisus battandieri Maire, Plantago lanceolata L., Digitalis purpurea L., Lonicera periclymenum L.     

Trinucleotide repeat microsatellite markers for black poplar (Populus nigra L.)

Using an enrichment procedure, we have cloned microsatellite repeats from black poplar (Populus nigra L.) and developed primers for microsatellite marker analysis. Ten primer pairs, mostly for trinucleotide repeats, produced polymorphic fragments in P. nigra. Some of them also showed amplification in other poplar species. (P. deltoides, P. tricocarpa, P. tremula, P. tremuloides, P. candicans, P. lasiocarpa). The best six loci were tested on 23 P. nigra genotypes collected across Europe. The microsatellites produced up to 12 alleles per locus in this set, with observed heterozygosity between 0.32 and 0.91.     

Changes in Polygalacturonase Activity and Solubility of Polyuronides during Ethylene-stimulated Leaf Abscission in Sambucus nigra

Leaflet abscission in Sambucus nigra is precipitated by cellwall degradation which is restricted to the site of cell separation.Accompanying wall breakdown is an increase in the activity ofthe enzyme polygalacturonase (PG) (E.C. 3.2.1.15 [EC] ) and this riseis primarily confined to the abscission zone tissue. The polygalacturonasehas a pH optimum of 4·4 and has the characteristics ofan endo-acting enzyme. The elevation in enzyme activity is theresult of an increase in at least two isoforms of PG as revealedby polyacrylamide gel electrophoresis of the natured protein.Leaflet abscission in S. nigra is associated with an increasein the solubility and depolymerization of polyuronides fromthe cell wall. These observations are discussed in relationto the mechanism of cell separation during ethylene-stimulatedleaf abscission. Key words: Elder, Sambucus nigra, abscission, polygalacturonase, polyuronides, ethylene     

Chloroplast DNA variation in Populus. I. Intraspecific restriction fragment diversity within Populus deltoides,P. nigra and P. maximowiczii

We examined intraspecific chloroplast (cp) DNA variation within Populus deltoides, P. nigra, and P. maximowiczii by restriction fragment analysis using 16 restriction endonucleases and six heterologous probes of cloned Petunia cpDNA fragments. All three Populus species showed intraspecific cpDNA variation, which was intra- and inter-varietal in P. deltoides, intervarietal in P. nigra, and origin-specific in P. maximowiczii. Two varieties of P. deltoides, var deltoides and var occidentalis, showed distinct cp genomes/DNA. Three distinct cp genomes/DNA, separated by a loss or gain of 1 EcoRV restriction site and/or 1 restriction fragment length polymorphism (RFLP), were observed among the individuals of P. deltoides var deltoides. Within P. nigra, cpDNA of var italica was distinct from that of vars nigra and plantierensis by one RFLP and by a loss or gain of one BamHI restriction site. Populus maximowiczii clones of Chinese origin were separated from those of Japanese origin by a gain or loss of one ClaI restriction site in their cpDNA. The estimate of nucleotide substitutions per site in cpDNA was 0.07% between two varieties of P. deltoides, 0.05% between var italica and var nigra or plantierensis of P. nigra, and 0.01% between Japanese and Chinese accessions of P. maximowiczii.     

Effect of volatiles emitted from wilted Populus nigra L. leaves on the mating and oviposition of Helicoverpa armigera (Hübner)

Wilted black poplar, Populus nigra ‘Italica’ L., leaves are very attractive to a vast number of noctuid moth species. This provides an opportunity for the development of effective trapping methods for the integrated management of pest species, such as Helicoverpa armigera, a major global and economically important insect pest.In the present study, we investigated the (1) nocturnal attraction patterns of H. armigera males and females to wilted P. nigra leaves; (2) effects of P. nigra volatiles on the mate-searching behavior of males through laboratory serial-chamber bioassays and field trapping; and (3) effects of P. nigra volatiles on the ovipositional choice and reproductive performance of females. Females and males, when tested alone, could be attracted by wilted P. nigra leaves, and the time periods of the first two attraction peaks were largely overlapped between sexes. Streams consisting of wilted P. nigra leaves and virgin females were not more attractive than virgin females alone, regardless of the stream sequence in a serial chamber. However, a stream of virgin females passed through wilted P. nigra leaves was more attractive than wilted P. nigra leaves alone. The addition of P. nigra extracts and its major aromatic components to the sex lure of H. armigera did not attract more moths than the sex lure alone. The volatiles from wilted P. nigra leaves were significantly more attractive to ovipositing females than those from cotton, tomato, and corn leaves, but equally attractive to tobacco leaves. Females exposed to volatiles from different leaves (P. nigra, cotton, and tobacco) showed similar fecundities. In summary, the attraction of moths to wilted P. nigra leaves may be attributable to multiple mechanisms, including the adsorption of sex pheromones, ovipostional attraction, and possible feeding attraction.