Post‐fire shrub recruitment in a semi‐arid grassland: the role of microsites

Question: (1) Which factors regulate post‐fire recruitment and spread of the shrub Senecio bracteolatus in Patagonian grasslands? (2) What is the role of the grass Stipa speciosa on S. bracteolatus establishment in the post‐fire succession? Location: Northwest Patagonia, Argentina. Methods: We studied the effect of fire on S. bracteolatus recruitment and density by comparing these variables between burned and unburned grasslands. In burned areas, we compared abiotic characteristics and seedling establishment under the canopy of grasses (S. speciosa) and in gaps (inter‐tussock areas). Post‐fire interactions between S. bracteolatus seedlings and S. speciosa were studied using field and greenhouse experiments. Results: Density of S. bracteolatus was higher in burned than in unburned areas. In burned sites, seedlings were more abundant under tussock grasses, whereas juveniles were more abundant in gaps. Tussocks generated more attenuated micro‐environmental conditions than gaps during stressful summers. Gaps were more abundant in burned sites, while “under tussock” microsites were more frequent in unburned sites. In burned areas, tussocks allowed higher establishment of seedlings (facilitation), but gaps allowed more seedling growth and higher persistence of juveniles. Conclusions: Fire promoted S. bracteolatus recruitment in Patagonian grasslands by increasing the availability of favourable gap microsites. Grass protection for shrub seedlings became negative with time, probably due to competition with grasses. Gaps led to better performance and persistence of shrub plants. Six years after fire, higher shrub recruitment and adult density (observed as a trend) in burned grassland provides an opportunity for potential S. bracteolatus invasion.     

NATURAL HYBRIDS BETWEEN ORYZOPSIS AND STIPA. I. ORYZOPSIS HYMENOIDES × STIPA SPECIOSA

Johnson , B. Lennart . (U. California, Los Angeles.) Natural hybrids between Oryzopsis and Stipa. I. Oryzopsis hymenoides × S. speciosa. Amer. Jour. Bot. 47(9): 736–742. Illus. 1960.—Spontaneous, sterile hybrids between Oryzopsis hymenoides and Stipa speciosa heretofore have been referred to O. bloomeri, which species in an earlier paper was shown to consist of a series of hybrids between O. hymenoides and various species of Stipa. On many morphological characters (O. hymenoides × speciosa) is intermediate between its parents and similar to the other hybrids formerly classed as O. bloomeri. It is distinct from the other hybrids on characters which reflect S. speciosa, except with respect to indument of the awn which is recessive. Somatic chromosome counts are: O. enoides, 48; S. speciosa, 64; hybrid, 56. Both parents exhibit regular bivalents at meiosis. The hybrid shows only occasional bivalents and mostly asynchronous splitting or random distribution of univalents at metaphase I. Pollen abortion is complete. No evidence of natural amphiploidy or introgression was found.     

Differential acidity tolerance of tropical legumes grown for green manure in acid sulfate soils

The growth of four tropical legumes (Cajanus cajan, Sesbania aculeata, S. rostrata, and S. speciosa) used as green manures in the tropics was studied in a glasshouse experiment. Two acid sulfate soils (Typic Sulfaquept, Bang Pakong Series; and Sulfic Tropaquept, Rangsit Series) were adjusted to four pH levels: 3.8 or 4.0 (original soil pH), 4.5, 5.5, and 6.5 (amended with lime). Dry weight was determined 49 days after sowing. Concentrations of N, P, K, Ca, Mg, Fe, Mn, and Al were also determined in aerial plant parts at harvest.The legumes responded differently to soil acidity and liming, but not to soil type. Cajanus cajan had the highest biomass production, followed by S. aculeata, S. rostrata and S. speciosa, in this order. The N concentration closely paralleled biomass production, suggesting that the growth of symbiotic rhizobia and nodulation were perhaps more susceptible to soil acidity than were the host plants. Liming to pH 5.5–6.0 was recommended for the legumes' growth based on the quadratic relationships between dry-matter yield and soil pH. In the unlimed soils, the Ca concentration in C. cajan and S. aculeata (0.32%) was twice as high as that in the two low-yielding legumes (0.15%). Furthermore, plant Ca increased exponentially (or quadratically in case of S. speciosa) as lime additions increased. It was estimated that for adequate growth, the Ca requirement in the shoot dry matter was approximately: C. cajan 1.2% Ca, S. aculeata 0.8%, S. rostrata 0.6%, and S. speciosa 0.4%. In contrast with Ca, the concentration of Fe, and to a lesser extent Mn, was significantly lower in C. cajan and S. aculeata than in S. rostrata and S. speciosa. The ratio of Ca to Al in plant tops was used to characterize plant tolerance to soil acidity, and to quantify the critical Al concentration in the plants. It appears that 90% maximum growth was attained only when Ca/Al was 150 for C. cajan and S. speciosa, 200 for S. rostrata, and 300 for S. aculeata. Cajanus cajan tolerated up to 80 mg Al kg^-1 in the shoot dry matter, whereas significant growth reduction occurred in the Sesbania species at levels > 30 mg Al kg^-1.     

Investigacion de levaduras en vulva y vagina

Resumen Se estudiaron 200 mujeres de primera consulta, sin tratamiento, que asistieron a la consulta externa de Ginecología del Hospital Universitario de Caracas, con el objeto de investigar la presencia de levaduras en vulva y vagina.Se tomaron 4 muestras de cada paciente: 2 de vulva y 2 del fondo de saco vaginal. Una muestra de vulva y una de vagina se destinaron al exámen directo (en fresco y con NaoH + tinta Parker Super Quink) y las otras muestras de vulva y vagina se utilizaron para cultivo en bilis-agar y lactritmel.Se encontraron 71 casos positivos especificados así:Trichomonas vaginalis, 38 (19 %);Candida albicans, 21 (10.5 %);Candida parapsilosis, 6 (3 %);Candida tropicalis, 5 (2.5 %);Torulopsis (holmii 2,candida 1) = 3 (1.5 %);Saccharomyces delbrueckii, 2 (1 %);Debaryomyces hansenii, 1 (0.5 %);Candida tenuis, 1 (0.5 %).Para el diagnóstico de la candidiasis y/o tricomoniasis vulvovaginal las manifestaciones clínicas no tienen ningún valor. El exámen directo, cuando es positivo, con presencia de filamentos y blastosporos, confirma el diagnóstico de candidiasis; pero su negatividad no excluye la presencia deCandida albicans como habitante de la vulvovagina en mujeres aparentemente normales.Los autores recomiendan la toma de la muestra des de la vulva para la investigación deCandida albicans, lo que facilita el exámen por no hacerse necesario el uso delspeculum; en cambio, paraTrichomonas vaginalis recomiendan la toma de la muestra desde el fondo de saco vaginal.El medio bilis-agar es el más apropiado para la rápida identificación deCandida albicans en el cultivo naciente, ya que en él se forman las clamidosporas en 24–48 horas.

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The cases of 200 women, without treatment, who attended the first gynecological external consultation at the Hospital Universitario, Caracas, Venezuela, were studied for the purpose of investigating the presence of yeast — like fungi in the vulva and in the vagina.Four samples were taken from each patient: two from the vulva and two from the posterior fornix. One sample each from the vulva and from the vagina were used, in direct examination, under microscope with NaOH + Parker/Super Quink ink; the remaining vulva and vagina samples were utilized in bilis-agar and lactritmel cultivation.71 positives cases were found, specified as follows:Trichomonas vaginalis, 38 (19 %);Candida albicans, 21 (10.5 %);Candida parapsilosis, 6 (3 %);Candida tropicalis, 5 (2.5 %);Torulopsis (holmii 2,candida 1) = 3 (1.5 %);Saccharomyces delbrueckii, 2 (1 %);Debaryomyces hansenii, 1 (0.5 %);Candida tenuis, 1 (0.5 %).In the diagnosis of vulvo-vaginal candidiasis and/or trichomoniasis the clinical signs have no significance. The direct examination, when positive, with presence of mycelium and blastospores confirms the diagnosis of candidiasis. However, if negative, it does not exclude the presence ofCandida albicans as habitant of the vulvo-vagina among apparently normal women.The authors recommended the taking of samples from the vulva for the purpose of investigation ofCandida albicans, which would facilitate the examination, inasmuch as it would be unnecessary to use the speculum. On the other hand, in the examination ofTrichomonas vaginalis the taking of samples from the posterior fornix is recommended.The bilis-agar medium is the most appropriate for the rapid identification ofCandida albicans from original cultures, as clamydospores are becoming present in 24 to 48 hours.

     

Evaluation of Sesbania speciosa as a green manure for lowland rice in the dry zone,Sri Lanka

Sri Lankan rice farmers rarely practise green manuring and they depend mostly on chemical fertilizers for the nutrient requirement of their crops. With the removal of government subsidy on fertilizers since 1990, they are now faced with the dilemma of meeting the cost of production to sustain previous yield targets. Therefore the present study devotes to evaluate alternative cheaper nutrient sources like green manures for rice. Results of recent work in Sri Lanka have shown that Sesbania speciosa Taub. ex Engl. is a promising green manure for lowland rice in the dry zone. It was evaluated to adopt a suitable green manuring system for rice. Its year-round biomass production, nutrient accumulation during the vegetative growth and nitrogen fixation were monitored. Field trials were conducted to investigate its ability to suppress weed growth when grown during fallow periods and its contribution to soil fertility and effect on rice yield. Highest biomass of around 100 g dry matter per plant, was achieved when S. speciosa was seeded in August and harvested at flowering in November. When this was planted during a fallow period at a spacing of 0.25×0.25 m (16 plants m^-2), percentage weed reduction was as much as 40%. Its N₂ fixation activity was similar to that of S. sesban (L.) Merr., Nitrogen concentration in S. speciosa increased until 70 days after establishment and then decreased towards flowering. Phosphorus and K accumulation was also effective during this period. Therefore suitable time for soil-incorporation of S. speciosa is around 70 days after establishment. S. speciosa-manured and chemically fertilized rice crops were comparable in terms of grain yield, indicating the effective nutrient supplying potential of this green manure. Straw biomass was significantly high under S. speciosa, because of the high N-allocation to vegetative growth of rice under this. This evaluation shows that S. speciosa not only supplies N, but is also an effective and complete supplier of other nutrients for rice. A scheme to introduce this into rice production system is proposed, where S. speciosa is seeded/broadcast two weeks before crop harvest (around January) in Maha (major) season as well as Yala (minor) season (around June) so that its biomass can be incorporated into soil during land preparation of subsequent seasons.     

l-glutamate transport in Lactobacillus helveticus

An energy source (glucose or lactose) was required for the transport of l-glutamic acid by Lactobacillus helveticus. Mg²⁺, K⁺ and Li⁺ increased its accumulation while Ca²⁺ and Na⁺ decreased it. It was inhibited by NaF, indicating that ATP may be involved in uptake. Optimum transport was at pH 7.3 and 45°C. l-Glutamic acid transport showed a high degree of stereospecificity, as neither d-glutamate nor d-aspartate were active. Proton-conducting uncouplers, like carbonyl cyanide-m-chlorophenylhydrazone, and ionophores (nigericin, monensin and gramicidin) were strongly inhibitory. These results indicate that a proton motive force may be involved in the transport of l-glutamic acid.The authors are with the Centro de Referencia para Lactobacilos, Chacabuco 145 4000 S.M. de Tucumán, Argentina and the Cátedra de Microbiologia Superior, Universidad Nacional de Tucumán, Argentina.     

<Emphasis Type="Italic">Manayunkia speciosa</Emphasis> Leidy (Polychaeta: Sabellidae): introduction of this nonindigenous species in the Neotropical Region (Uruguay river,South America)

We report the migration of Manayunkia speciosa from its distribution in North America into the Neotropical Region (Argentina). We collected specimens from November 2007 to March 2009 in the lower Uruguay River-at 33° 5.01′S 58° 12′W, 33° 5.9′S 58°25.2′W from sediments reaching densities of 2,890 ind. m⁻², at a mean abundance of 350 ind. m⁻². Introductions of nonindigenous species, resulting intentionally or accidentally from anthropic activities, cause significant changes in ecosystems. In aquatic environments, polychaetes are a key invasive group that increases the geographical range of several species through human activities. M. speciosa may have reached the Río de la Plata Basin through a shipping vector and thereafter the Uruguay River by self-navigation.     

Application of immunoprecipitation techniques to the diagnosis of cutaneous and extracutaneous forms of sporotrichosis

Sporotrichosis is a mycosis which in our country has been described as only producing cutaneous and subcutaneous infections; in other countries it has been reported as causing pulmonary, bone, joint and meningeal infections.Possibly the systemic form also occurs in Venezuela since, along with the causative agent, all other factors considered as predisposing to systemic infection exist here.Through immunodiffusion (ID) and immunoelectrophoresis (IEP) and using a filamentous form metabolic antigen from Sporothrix schenckii, we were able to demonstrate precipitating antibodies against this fungus both in patients with cutaneous sporotrichosis, diagnosed by culture of the infecting agent, and in patients with pulmonary lesions. The IEP test showed the presence of an anodic arc which we have called the S arc, which could be one of the specific antigens of S. schenckii.

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Resumen En Venezuela, el diagnóstico de la esporotricosis solo se plantea ante lesiones cutáneas y subcutáneas, sin embargo, no deja de llamar la atención que siendo esta micosis la más frecuente en nuestro medio y existiendo concomitantemente en la población todos los factores predisponentes para que el S. schenckii invada órganos internos, estas localizaciones no han sido descritas.La incorporación del antígeno del S. schenckii para detectar anticuerpos circulantes en la ID en nuestros estudios serológicos de rutina, nos permitió observar la presencia de bandas de precipitación contra este antígeno en sueros de pacientes con lesiones pulmonares, igualmente fueron detectados anticuerpos en pacientes con esporotricosis cutáneas diagnosticadas por cultivo.El estudio de la estructura antigénica de este hongo, puso de manifiesto la presencia de un arco de localización anódica, que podría ser producido por uno de los antígenos específicos de este hongo; este arco que denominamos S fue visualizado en todos los casos positivos de esporotricosis cutáneas, al ser estudiados sus sueros en la IEF.Los estudios realizados en sueros de pacientes con lesiones pulmonares pusieron de manifiesto anticuerpos precipitantes en la ID e IEF, con las caractéristicas de evidenciar más de una línea de precipitación en la ID y un arco S más largo en la IEF, pudiendo ser esto originado por mayor producción de anticuerpos circulantes. Se plantea la necesidad de obtener el cultivo del S. schenckii de las posibles lesiones extracutáneas de esta micosis.

     

A test for lottery recruitment among four Banksia species based on their demography and biological attributes

A stage-by-stage protocol for identifying simple or biased lottery, or non-lottery, patterns of seedling recruitment is outlined. For a simple (weighted) lottery to apply, the proportion of total individuals accounted for by one species at one stage of recruitment plotted against the proportion accounted for at a previous stage over a wide range of recruitment conditions should obey a linear regression with a=0 and b=1. For a biased lottery to hold, the regression is significant but a0 and/or b1. Demorgraphic, size and water relations data were collected over 3 years for four co-occurring Banksia species following two contrasting experimental fires. The first summer was exceptionally wet and the second was exceptionally hot and dry. Seedlings still alive by the 3rd year relative to the fire-killed parent plants conformed to a biased lottery in the case of B. speciosa and B. baxteri, while B. coccinea and B. pulchella had no mathematical structure (mean of the proportional ratios 1). Intervening stages, beginning with seed release, showed transient deterministic or simple lottery patterns in some cases, but the overriding trend was for biased lotteries. B. speciosa dominated the responses, with greater seed release than expected, fewer initial seedlings, lottery survival of 1st year seedlings and greater survival of 2nd year seedlings, when compared with the previous stages. Large seeds and subsequent high growth rates enabled B. speciosa to exploit soil water preferentially during the severe summer drought. The trend for B. speciosa to replace other species may be cancelled by stochastic processes not operating in this particular study.     

Spatial pattern of size distribution of four fish species on Réunion coral reef flats

A comparative study of the size distribution of four fish species was performed on three geomorphological zones (back reef, inner reef flat and outer reef flat) on two comparable fringing reef areas (disturbed and non-disturbed) of Reunion Island, S. W. Indian Ocean. The species chosen Chaetodon trifasciatus, Dascyllus aruanus, Stethojulis albovittata and Ctenochaetus striatus were selected both for their abundance and their diverse diets. The method used is based on the estimation of fish size directly underwater by comparison to a graduated table, i.e. photographs of the species for which different size-classes were previously determined. For the two areas, the size of fishes increases from the back reef zone to the outer reef flat, except for D. aruanus which is not present in sufficient numbers on the outer reef flat to allow a statistical analysis. This suggests the existence of a nursery zone in the back reef from which these species might colonize the reef flat. On the back reef zone and the inner reef flat, there is a significant difference in the size distribution of fishes between the disturbed and non-disturbed areas, except for S. albovittata. The number of juveniles is significantly lower in the disturbed area, probably due to environmental perturbations.

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Résumé Une étude de la distribution des tailles de quatre espéces de poissons coralliens a été réalisée sur trois zones géomorphologiques (arriére récif, platier interne et platier externe) de deux secteurs récifaux comparables (dégradé et non dégradé) de l'île de la Réunion, océan Indien occidental. Les espéces étudiées, Chaetodon trisfaciatus, Dascyllus aruanus, Stethojulis albovittata et Ctenochaetus striatus ont été choisies pour leur abondance et leur diversité de régime alimentaire. La technique utilisée consiste á estimer la longueur du poisson directement sous l'eau á l'aide d'une tablette graduée. Des photographies de poissons de différentes tailles, préalablement définies, y ont été fixées, et ceci pour les quatre espéces. Pour les deux secteurs, une augmentation réguliére de la taille des poissons depuis l'arriére récif jusqu' au platier externe est apparue, sauf pour D. Aruanus ui n'est apas suffisamment abondante sur le platier externe pour permettre une analyse statistique. Ces observations suggérent l'existence d'une nurserie dans l'arriére récif á partir duquel pourrait s' opérer la colonisation du platier récifal. Dans les zones d' arriére récif et de platier interne, il y a par ailleurs une différence significative dans la distribution des tailles des poissons entre le secteur dégradé et le secteur non dégradé, sauf pour S. albovittata. Le nombre des juvéniles est significativement plus faible dans le secteur dégradé, ce qui pourrait être dû aux dégradations de l'environment corallien.

     

Description de Syphabulea mascomai n. sp. et analyse du genre Syphabulea

Syphabulea mascomai n. sp., parasite de Sciurus vulgaris (L.) en Espagne, est décrite. S. mascomai se distingue des autres espèces du genre par: (i) la grande taille de ses oeufs; (ii) la taille relativement réduite de l'opercule de ces oeufs; (iii) par les particularités de l'ornementation du crochet accessoire au gubernaculum. La systématique et la répartition géographique des espèces du genre Syphabulea Gubanov, 1964 sont discutées. L'espèce type du genre est Syphabulea tjanschani (Ablasov, 1962) n. comb. [= Syphacia sp. d'Ablasov in Skrjabin et al. (1960); =Syphacia tjanschani Ablasov, 1962; =S. toschevi Petrov & Bayanov, 1962; =S. thompsoni sensu Li (1933); =S. thompsoni sensu Gubanov (1964); = Syphabulea sobolevi Gubanov, 1964]. Le genre Syphabulea n'était jusqu'ici connu que dans le région orientale, la région néarctique, et l'Est de la région paléarctique. La découverte d'un nouveau Syphabulea dans la péninsule ibérique, dont la faune parasitaire présente des caractères endémiques et relictuels, montre que la présence de ce genre dans la région paléarctique est probablement ancienne. Le genre Syphabulea est sympatrique du genre Rodentoxyuris Quentin & Tenora, 1975, lui aussi spécifique de Rongeurs Sciuroidea, dans une partie importante de la région holarctique. Syphabulea mascomai n. sp., parasitic in the caecum and large intestine of Sciurus vulgaris (L.) in Spain, is described. S. mascomai is characterised by: (i) its very large eggs; (ii) a shorter operculum on the eggs; and (iii) by the peculiar shape of the ornamentation of the accessory piece of gubernaculum. The systematics and the zoogeographical range of the genus Syphabulea Gubanov, 1964 are discussed. The type-species of the genus is: Syphabulea tjanschani (Ablasov, 1962) n. comb. [=Syphacia sp. of Ablasov in Skrjabin et al. (1960); =Syphacia tjanschani Ablasov, 1962; =S. toschevi Petrov & Bayanov, 1962, = S. thompsoni sensu Li (1933); =S. thompsoni sensu Gubanov (1964); =Syphabulea sobolevi Gubanov, 1964]. Until now the genus Syphabulea was known only from the Oriental region, from the Nearctic region and from the asiatic part of the Palearctic region. The discovery of a new species from Spain, an area in which the parasitological fauna exhibits endemic and relictual characteristics, indicates that this genus has probably been present in this part of Europe for quite a long time. The zoogeographical range of genus Syphabulea involves most of the Holarctic region, where it is sympatric with Rodentoxyuris Quentin & Tenora, 1975, another genus parasitic in the Sciuroidea.Se describe a Syphabulea mascomai n. sp. como parásito de Sciurus vulgaris (L.) en España. S. mascomai se distingue de las otras especies del género por: (i) el gran tamaño del los huevos; (ii) el tamaño, relavitamente reducido, del operculo de los huevos; (iii) las características de la ornemantación del gancho accesorio del gubernáculo. Se discute la sistemática y la repartición geográfica de las especies del género Syphabulea Gubanov, 1964. La especie tipo es: Syphabulea tjanschani (Ablasov, 1962) n. comb. [= Syphacia sp. del Ablasov in Skrjabin et al. (1960); =Syphacia tjanschani Ablasov, 1962; =S. toschevi Petrov & Bayanov, 1962; =S. thompsoni sensu Li (1933); =S. thompsoni sensu Gubanov (1964); = Syphabulea sobolevi Gubanov, 1964]. Hasta el presente se tenían datos del género Syphabulea en la Región Oriental, la Región Neártica y en el este de la Región Paleártica. El hallazgo de Syphabulea en la Península Ibérica, donde las parasitofaunas presentan características endémicas y relictuales, viene a sugerir que la presencia del género en la Región Paleártica es muy antigua. El género Syphabulea es simpátrico del género Rodentoxyuris Quentin & Tenora, 1975, tambien específico de Roedores Sciuroidea en la mayor parte de la Región Holártica.     

A presumed case of functional convergence between the flowers of Schizolobium parahyba (Fabaceae) and species of Malpighiaceae

Flowers of Malpighiaceae have a flag petal with a sturdy base that Centridini bees clasp with their mandibles to free their legs and thus be able to harvest oil. We found that the yellow, nectariferous flowers of Schizolobium parahyba (Fabaceae) have a forward-flexed upper petal with a sturdy claw and an adnate filament. Two Centris species were among the most frequent bee visitors to S. parahyba flowers. These bees clasped the adnate filament and the claw of the upper petal with their mandibles and extended their mouthparts into the corolla to take nectar. During the visit they leaned on, or loosely grabbed, the stamens. Blooming in the same area and period were two yellow-flowered Stigmaphyllon species (Malpighiaceae) whose pollen was also found on loads carried by the Centris bees. The flexion and the sturdiness of the upper petal claw of Schizolobium parahyba flowers may be viewed as a trait that suits the mandible clasp of Centris bees. Although this clasp is not needed when the bees visit S. parahyba flowers, it is vital when the bees exploit flowers of the Malpighiaceae. We suggest that the sturdy claw and the adnate filament of S. parahyba may be viewed as an instance of presumed functional convergence with the upper petal of Malpighiaceae.     

Contribution to the taxonomy and phylogeny of Sarcocapnos DC. (Fumariaceae)

 To solve problems concerning the status of the taxa described in the genus Sarcocapnos, we have conducted a study using morphological, pollen morphology (light microscopy), cytogenetic and molecular techniques. Focusing on the last technique, we have sequenced ITS-1 and ITS-2 of nuclear rDNA. The species differ basically according to 5 morphological traits (leaf shape, flower spur, corolla colour, corolla size, and crest of the stigmatic surface). The cytogenetic analyses indicated n=16 to be the standard chromosome number. The ITS analyses showed that the genus is monophyletic, defining two main well-supported clades, one containing S. saetabensis and S. enneaphylla, and one containing the rest of the species. In this second clade, S. speciosa, S. pulcherrima, and S. baetica subsp. ardalii are related, as are S. integrifolia, S. crassifolia subsp. crassifolia, and S. crassifolia subsp. atlantis; S. baetica subsp. baetica forms a trichotomy with the foregoing groups. S. speciosa is shown to be a species separate from S. crassifolia subsp. crassifolia, as in the case of S. baetica with respect to S. integrifolia. Palynologically, the parameters used enabled us to establish clear differences between the taxa, often corroborating the macromorphological and genetic data. The flower spur has been reduced several times in different groups of the genus, for which the classifications established on the basis of this trait are paraphyletic. Received July 16, 2002; accepted December 11, 2002 Published online: March 31, 2003     

Seasonal development of secondary xylem and phloem in <Emphasis Type="Italic">Schizolobium parahyba</Emphasis> (Vell.) Blake (Leguminosae: Caesalpinioideae)

The cambial activity and periodicity of secondary xylem and phloem formation have been less studied in tropical tree species than in temperate ones. This paper describes the relationship between seasonal cambial activity, xylem and phloem development, and phenology in Schizolobium parahyba, a fast growing semideciduous seasonal forest tree from southeastern Brazil. From 2002 to 2003, wood samples were collected periodically and phenology and climate were recorded monthly in the same period. S. parahyba forms annual growth increments in wood, delimited by narrow initial parenchyma bands. The reduction of the cambial activity to a minimum correlates to the dry season and leaf fall. The higher cambial activity correlates to the wet season and the presence of mature leaves. In phloem, a larger conductive region was observed in the wet season, when the trees were in full foliage. The secondary phloem did not exhibit any incremental zone marker; however, we found that the axial parenchyma tends to form irregular bands.     

Using tree population size structures to assess the impacts of cattle grazing and eucalypts plantations in subtropical South America

To evaluate the effects of distinct management of the matrix in which forest fragments are found upon plant populations thriving in forest remnants in south Brazil, we assessed the conservation status of populations of four woody species (Campomanesia rhombea, Diospyros incontans, Myrciaria cuspidata and Sebastiania commersoniana) through analyses of size structure. Analyzes were carried out at two scales. At a local scale, we consider populations in fragments surrounded by pastures or eucalypts forest plantations, and at a regional scale we also consider larger forest tracts taken as reference areas (Rio Grande do Sul Forest Inventory databank). Population size structures were summarized using the symmetry of height distributions. Small individual size classes prevailed at the local scale in fragments surrounded by eucalypts plantations, whereas in areas exposed to cattle ranching, populations of the same species consistently lack small individuals. At the regional scale, populations in fragments surrounded by pastures presented greater skewness (prevalence of small plants) than populations in reference areas, while populations surrounded by eucalypts plantations presented intermediate skewness. These results reinforce the notion that plantations have a higher conservation value for forest ecosystems than other commercial land uses, like cattle ranching.     

Organellar DNA restriction fragment length polymorphism (RFLP) and nuclear random amplified polymorphic DNA (RAPD) analyses of morphotypes of Gracilaria (Gracilariales,Rhodophyta) from Chile

The extreme phenotypic variability recognized among the species of Gracilaria has highlighted the need for the application of refined methods to help solve taxa identifications. In Chile, there still exists uncertainty about the exact number of Gracilaria species. Our investigations are centered on DNA analyses of morphotypes collected from different geographical locations, namely Lenga and Isla Santa María, Region VIII (36°00 S to 38°00 S), and Maullín, Region X (39°30 S to 43°40 S). These two regions of Chile are considered as areas of confluence of G. chilensis, G. verrucosa, and a species of Gracilariopsis. In this study four morphotypes, from a natural bed located in Maullín, were analyzed for RFLP of plastid DNA and the results compared with data of four morphotypes from a bed in Lenga. The DNA banding patterns from each enzyme digest were identical irrespective of morphotypes and/or locations. In an attempt to unravel the nature of the morphological differences found among Lenga and Maullín morphotypes, RAPD analyses of nuclear DNA were also performed; however, no polymorphism has been found yet. Therefore, the data of this study, as well as concurrent data from preliminary interfertility tests, suggest that all morphotypes belong to a single taxon, Gracilaria chilensis.Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas     

Rupicolous vegetation of the betic ranges (south Spain)

On rupicolous vegetation (cl. Asplenietea trichomanis) of the Betic ranges in south Spain. The endemic alliance Saxifragion camposii developed in the upper zones of this area is here thoroughly examined. Phytosociological tables with records of all the syntaxa and biogeographical, ecological and floristic data among others are shown. Finally, as a result of a profound syntaxonomical discussion and the last data available the synopsis of this alliance is completed with four new associations: Hieracio texedensi-Moehringietum tejedensis, Athamanto hispanicae-Sideritetum stachydioidis, Sileno andryalifoliae-Saxi-fragetum camposii, Jasiono minutae-Saxifragetum rigoi.

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Resumen Se estudia la vegetación rupícola (cl. Asplenietea trichomanis) de las Cordilleras Béticas, emplazadas en el sur de España. En los territorios más elevados de estas se desarrolla la alianza endémica Saxifragion camposii, cuya revisión completa se realiza en este trabajo. Se aportan tablas fitosociológicas de todos los sintáxones, así como datos de tipo biogeográfico, ecológico, florístico, etc. Como resultado de una profunda discusión sintaxonómica y con los nuevos datos disponibles, se completa el esquema de la mencionada alianza con cuatro asociaciones nuevas (ver resumen en inglés).

     

Leaf anatomy inTigridieae (Iridaceae)

A biometric study of theSarcocapnos crassifolia complex from eastern Andalusia (Spain), Algeria, and Morocco was carried out. Twentytwo populations were used in a principal components analysis based on 14 variables. The results support the recognition of two species,S. crassifolia andS. pulcherrima, spec. nova. The taxon described byBoissier asS. speciosa (S. crassifolia subsp.Speciosa) is maintained inS. crassifolia.     

PREDATION IN INSULAR PLANT DYNAMICS: AN EXPERIMENTAL ASSESSMENT OF POSTDISPERSAL FRUIT AND SEED SURVIVAL,ENEWETAK ATOLL,MARSHALL ISLANDS

We studied predation upon the fruits of four common terrestrial plant species of atolls by excluding: 1) all predators; 2) large predators only; and 3) no predators. Each of these treatments was located within the vegetation at three distances from the shore: beach edge of fringing thicket; middle of the thicket; and inner forest. The plants were Terminalia catappa, Messerschmidia argentea, Scaevola taccada, and Guettarda speciosa. Predation loss over the year was significant (P > 0.01) for all four species. Location contributed significantly only for S. taccada. Amount of loss and predominant type of seed predator for a plant species were related to size and conspicuousness. The largest fruits, those of the widespread tree T. catappa, were destroyed completely at all sites; the damage was done by both insects and terrestrial crabs. The large fruits of G. speciosa were destroyed by insects inland and by crabs at the beach edge. The small fruits of M. argentea, a plant which is common along the beach, tended to have greater losses away from the beach edge; those losses were caused primarily by insects. For S. taccada, which occurred at the beach edge, fruit survival was highest in the middle of the fringe thicket; average damage and disappearance were high and caused primarily by large predators. In sum, the experiment demonstrated that predation by widespread, omnivorous large animals and insects on an atoll island was important in survival of fruits and enclosed seeds. We conclude that this interaction could have a significant influence on the dynamics of plants on atolls.     

Bacterial protein production from corn cob pre-treated with NaOH at room temperature

Corn cobs were treated at room temperature with NaOH at a ratio of 100:3 (w/w), but with different volumes of water from 3 to 0.25 ml/g corn cob. The biomasses obtained from a mixture culture of Cellulomonas sp. and Bacillus subtilis under each condition were similar (5.5 to 6.0 g/l) and protein only varied between 30% and 40% (w/w biomass) or 1.9 and 2.2 g/l. Low volumes and low amounts of NaOH can therefore be used in a cost-effective manner.N. Pece is with the Cátedra de Quimica Orgánica, Universidad Nacional de Santiago del Estero, Argentina. N. Perotti and O. Molina are with the Cátedra de Microbiologia Industrial, Universidad Nacional de Tucumán, y PROIMI, Planta Piloto de Procesos Industriales Microbiológicos, Av. Belgrano y Pje Caseros, 4000 Tucumán, Argentina