ISOLATION OF N-PARAFFIN HYDROCARBONS FROM PSEUDOTSUGA MACROCARPA

Normal paraffin hydrocarbons of Pseudotsuga macrocarpa Mayr. collected from eight sites in California were compared with each other and with those of P. menziesii (Mirb.) Franco collected from two locations. Quantitative differences within the first species could not be correlated with geographic location. However, both the species could be separated completely on the basis of their (C₃₀H₆₂) triacontane content.     

Ineffective nodulation of Sesbania macrocarpa by Sinorhizobium meliloti strain RCR2011

Sinorhizobium meliloti is a well-known symbiont that fixes nitrogen with plants of three genera of the family Leguminosae, Tribe Trifolieae: Medicago, Melilotus, and Trigonella. We have found that S. meliloti strain RCR2011 forms ineffective nodules on a distantly related legume species, Sesbania macrocarpa. Nodules are indeterminate and lack leghemoglobin. Although S. meliloti deformed root-hairs of S. macrocarpa, infection threads were not detected in these cells. Instead, cells of S. meliloti were found in infection pockets between cortical cells and within infection threads that had penetrated into these cells. Bacteria eventually were released and gave rise to symbiosomes, which contained large quantities of an amorphous matrix with parallel arrays of electron-dense striations. Mutants of strain RCR2011 lacking nodA or nodH failed to nodulate S. macrocarpa, inactivation of nodG or nodE resulted in smaller nodules, while inactivation of region IIa, which contains nodIJ, had no apparent effect on nodulation.     

Produits neutres et alcaloides de Myrtopsis macrocarpa,M. myrtoidea,M. novae-caledoniae et M. sellingii

Stems and leaves of Myrtopsis macrocarpa, M. myrtoidea, M. novae-caledoniae and M. sellingii yielded terpenes, sterols, coumarins, alkaloids (furoquinolines and quinolones) and amides. A new quinolone (8-methoxy flindersine) occurs in Myrtopsis macrocarpa, a new amide (N-benzoyltryptamine) in M. myrtoidea, two new coumarins (myrsellin and myrsellinol) and a new dihydrofuroquinoline (myrtopsine) in M. sellingii. Structures of the new compounds are proposed from chemical and spectroscopic evidence.     

First report of fern (Culcita macrocarpa) spore consumption by a small mammal (Apodemus sylvaticus)

Few vertebrates are known to consume ferns regularly. Several species of mammals consume leaves to some extent but the consumption of fern spores is much rare. In Galicia (Northwest Spain) we studied the seasonal variation in the consumption of Culcita macrocarpa fertile leaves (i.e. with spores) in two populations (Capelada and Eume), assessed whether consumption rate increased with fern population size, and evaluated whether the consumer was a spore predator or a spore disperser. Consumption began in December and finished by mid February, and occurred before spore release, which happened later in Capelada than in Eume, probably influenced by differences in altitude. The consumer was identified as Apodemus sylvaticus by DNA analysis of its droppings and by capture of live animals. Throughout Galicia there was a significant increase in fern consumption rate as the population size of C. macrocarpa increased. Germination tests from droppings were carried out in 14 dishes but only in two dishes 1% and 0.3% of the spores germinated. Our results suggest that woodmouse can disperse spores of C. macrocarpa, although most of the spores were digested.     

A new species of Amanita section Lepidella from South China

Amanita macrocarpa from Guangdong Province of China is described. The new species is a large, brownish orange to light brown mushroom, characterized by numerous pyramidal warts on the pileus, yellowish lamellae, a large annulus at the middle of the stipe, and amyloid ellipsoidal basidiospores. Phylogenetic analyses of the new species and related taxa based on the large subunit of nuclear ribosomal DNA (LSU) and the internal transcribed spacer (ITS) sequences are provided. Morphological and molecular data show that A. macrocarpa is a member of Amanita, section Lepidella, and clearly different from any known taxon of the section.     

Initial constraints in seedling dynamics of Juniperus macrocarpa Sm.

The micro-forests dominated by Juniperus macrocarpa inhabiting coastal dunes in the Mediterranean Basin are European priority habitats. Their conservation is hindered by both anthropic and natural causes, although the regeneration problems for J. macrocarpa are still poorly understood. In this study, several factors influencing emergence and mortality of J. macrocarpa seedlings were investigated. For this purpose, permanent plots were placed in coastal dunes of Sardinia (Italy) and periodically monitored to record seedling parameters (emergence, survival and growth), as well as several biotic and abiotic variables (solar radiation, tree cover, herbaceous plus scrub cover, number of female cones on the soil and number of herbivory traces). Linear mixed models were fitted to test the effects of several types of explanatory variables on seedling dynamics. A total of 536 seedlings were marked, most of which emerged in winter. The microhabitat was the most important factor in models explaining emergence, with the number of emerged seedlings decreasing with solar radiation. Survival was very low, reaching the highest mortality percentage in the first summer. Herbivory and location in open interspaces had significant negative effects on seedling survival. In conclusion, the recruitment of J. macrocarpa is highly limited in the initial life cycle phases, with microhabitat and herbivory constraints influencing seedling dynamics. The identification of critical stages in the recruitment process of J. macrocarpa, together with factors influencing them, suggests some implication for management as well the hypotheses for future studies about conservation and recovery of the J. macrocarpa habitat.     

Field study on planted forest structures and their role in protecting communities against tsunamis: experiences along the coast of the Biobío Region,Chile

A field study using satellite images was carried out to analyze the effect of coastal vegetation in mitigating the impact of a catastrophic tsunami on coastal villages in the Biobío Region, Chile, in February 2010. Two types of stand, Pinus radiata D. Don forests and Cupressus macrocarpa Hartw. shelterbelts, appear to have protected coastal areas behind them from the direct impact of the tsunami. The impacts of the horizontal and vertical structures of these coastal forests on the drag forces were analyzed by observing the characteristics of Pinus radiata forests and Cupressus macrocarpa shelterbelts. The stands absorbed the impact of the tsunami without incurring broken stems or uprooted trees due to their diverse horizontal structure, as they contained short trees with various diameters. However, small areas of the stands were damaged by salinity after the tsunami. For this tsunami, which was less than 3 m high, the horizontal and vertical structures of the P. radiata and C. macrocarpa stands provided effective protection for coastal villages since they reduced the velocity and height of the tsunami. A shelterbelt consisting of three rows of C. macrocarpa in front of the tsunami and a P. radiata forest with a density of 11 trees/100 m² and a width of >50 m immediately behind the shelterbelt are suggested as a means of protecting communities along the coastline of the Biobío Region against tsunamis.     

Chemical constituents of Stenotaenia macrocarpa Freyn & Sint. (Apiaceae)

Phytochemical investigation of Stenotaenia macrocarpa Freyn & Sint. (Apiaceae) led to the isolation of ten known compounds: eight flavonoids (1–8) and two furanocoumarins (9–10). The chemical structures of the compounds were elucidated based on 1D and 2D NMR and MS spectra, as well as comparison with the relevant literature data. To the best of our knowledge, this is the first detailed phytochemical study about Stenotaenia macrocarpa and the first report on the isolation of all the compounds from the genus Stenotaenia, and manghaslin (2) and its methoxylated derivative typhaneoside (3) from Apiaceae. The chemotaxonomic significance of isolates was also discussed.     

What happens to the mycorrhizal communities of native and exotic seedlings when Pseudotsuga menziesii invades Nothofagaceae forests in Patagonia,Argentina?

Pseudotsuga menziesii is one of the most widely planted conifers in the Patagonian Andes of Argentina, having invading characteristics that are broadly reported. We studied the mycorrhizal status of seedlings along six Nothofagaceae + P. menziesii invasion matrices to investigate their role in the invasive process, according to these hypothesis: a) The abundance and richness of EM will be higher in seedlings grown in their own soil; b) In the presence of native EM inoculum, the invasive plant will be associated with generalist mycorrhizae (EM and/or AM), c) AM associations will be more abundant in P. menziesii seedlings grown in Interface or native forest soils, d) Mycorrhizal community differences between treatments will alter host fitness (growth and nutritional parameters). Seedlings from Nothofagus dombeyi, N. antarctica, Lophozonia alpina, L. obliqua and Pseudotsuga menziesii were set up in a soil-bioassay that included soils from non-invaded Nothofagaceae forests, pure P. menziesii plantations, and the interface between both. Pseudotsuga menziesii seedlings showed a decreasing, although never null, ectomycorrhizal (EM) colonization pattern from plantations to non-invaded forests, mainly with exotic EM species. Hebeloma mesophaeum and Wilcoxina sp. 1, two EM species with cosmopolitan distribution, were found to be shared by both tree species. Hebeloma hiemale and Wilcoxina sp. 1, common mycorrhizal partners of P. menziesii in Patagonia although not registered from Nothofagaceae forest, were found to be associated with N. antarctica, being the first report for both fungal species. Pseudotsuga menziesii seedlings showed the ability to form different arbuscular mycorrhiza (AM) colonization types (Paris-, Arum-, Both- and Intermediate-types) depending on the treatments, with significantly higher presence of Intermediate-type in the Interface treatment, where colonization was low. The shared EM species and the presence of different AM colonization types imply enhanced possibilities for invasive P. menziesii seedlings establishment and development. Seedling features and EM colonization rates evidenced that P. menziesii invasion could produce maladaptation (defined as a relative decline in host fitness due to altered mycorrhizal communities from native settings) of mycorrhizal communities, seriously injuring native ecosystem.     

Two dibenzofuran derivatives from fruits of Rhodomyrtus macrocarpa

Two new isomers of the natural dibenzofuran derivative, rhodomyrtoxin, have been isolated from Rhodomyrtus macrocarpa fruits and their structures determined by spectroscopic methods. A third compound, possibly ψ rhodomyrtoxin was isolated in smaller quantities.     

On the ecology of some species of genus <Emphasis Type="Italic">Stuckenia</Emphasis> (Potamogetonaceae) in lakes of Zabaykalsky krai and the Republic of Buryatia

This paper clarifies the distribution and ecology of representatives of the genus Stuckenia (S. chakassiensis (Kaschina) Klinkova, S. pectinata (L.) Börner, S. macrocarpa (Dobroch.) Tzvelev, and S. vaginata (Turcz.) Holub) in brackish and saline lakes in eastern Russia. It is shown that S. chakassiensis grows in most Transbaikal lakes with a high salinity instead of S. pectinata, as was described earlier. Therefore, the range of this interesting and still insufficiently known taxon significantly extends to the east of Russia. Being very common in the mineralized waters of West Siberia, S. macrocarpa was not observed in Transbaikalia. In soda waters of Transbaikalia, S. chakassiensis forms thickets with a rather high productivity.     

Comparative study of the sympatric ferns Culcita macrocarpa and Woodwardia radicans: Sexual phenotype

The sexual phenotypes of 1152 gametophytes from four populations of Culcita macrocarpa and Woodwardia radicans were monitored over a 1-year period. Gametophytes were maintained under three experimental conditions: (1) isolated, (2) pairs from the same sporophyte, or (3) pairs from different sporophytes. The frequencies of the sexual phenotypes did not vary significantly among these three conditions, and although there were some quantitative differences between populations, the sexual-phenotype sequences observed were species-specific. Gametophytes of C. macrocarpa were first male and then hermaphrodite: this sequence, together with the absence of antheridiogens, favours intragametophytic selfing. Natural populations of C. macrocarpa are presumably androdioecious. Gametophytes of W. radicans were first female and then hermaphrodite: this sequence and antheridiogen activity favour intergametophytic and even xenogamous mating. Despite these laboratory findings, populations of W. radicans are probably trioecious (because of the effects of antheridiogen). Few sporophytes of W. radicans were obtained in the present study, and none of C. macrocarpa: this is attributable to limiting illumination or substrate.     

A new subspecies and two new combinations of Nothofagus Blume (Nothofagaceae) from Chile

One new subspecies ofNothofagusBlume,Nothofagus obliquasubsp.andina, is described from Chile, and two new combinations have been madeNothofagus obliquasubsp.valdivianaandNothofagus macrocarpacomb. nov.     

The Importance of Large-Diameter Trees to Forest Structural Heterogeneity

Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥1 cm dbh, all 1,966 snags ≥10 cm dbh, and all shrub patches ≥2 m². Basal area of the 26 woody species was 62.18 m²/ha, of which 61.60 m²/ha was trees and 0.58 m²/ha was tall shrubs. Large-diameter trees (≥100 cm dbh) comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR) up to 9 m (P≤0.001). Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla), or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata). Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses.     

(+)-9α-Hydroxymatrine from Sophora macrocarpa

A new quinolizidine alkaloid, (+)-9α-hydroxymatrine, was isolated from the leaves of Sophora macrocarpa. Its structure was determined by a combination of spectroscopic methods, among which nuclear Overhauser enhancement experiments played a crucial role. Some generalizations are made regarding the mass spectra of matrinoids.     

An extract of Ulmus macrocarpa improves cellular immunity in immuno-suppressed models

An extract of Ulmus macrocarpa Hance, commonly known as the large-fruited elm, has been prescribed as a traditional medicine. In this study, we aimed to investigate the cellular immune effects of U. macrocarpa stem cortex extracts on cyclophosphamide (CY)-treated splenocytes and mice. A methanol extract showed an improved survival rate of splenocytes after 72?h. The extract was successively partitioned with dichloromethane, ethyl acetate, n-butanol, and water; and the fractions so obtained were also examined for their proliferative activity. Among them, the water fraction of U. macrocarpa showed the highest proliferation of splenocytes and was used throughout the present study. We tested the survival rate of splenocytes through dose-dependent treatment of CY and the suppression of the survival effect by CY was recovered by treatment with the water extract of U. macrocarpa. To determine the mechanism involved, we examined the expression of B-cell lymphoma-extra large (Bcl-xL) anti-apoptotic protein. CY decreased Bcl-xL protein levels in resting splenocyte cultures, whereas splenocytes were exposed to water extracts of U. macrocarpa in the presence of CY; however, elevations in Bcl-xL were observed at 96?h. Mice splenocytes treated with water extract of U. macrocarpa for cellular immunity showed an increase in the activity of the mixed lymphocyte reaction (MLR), cytotoxic T lymphocytes (CTLs), and natural killer (NK) cells. In addition, mice receiving a water extract of U. macrocarpa recovered the CTL, NK, and MLR activities suppressed by CY administration. Consequently, U. macrocarpa improves the cell-mediated immune response and provides an insight on cell-based tonic materials.