DIFFERENTIAL LIFE HISTORY PHASE EXPRESSION IN TWO COEXISTING SPECIES OF SCYTOSIPHON (PHAEOPHYCEAE) IN NORTHERN CHILE1

The identity of two phaeophycean taxa that monopolized the middle‐lower rocky intertidal zone of a coastal area chronically exposed to copper mine wastes in northern Chile was unraveled. One of them was preliminarily identified as the gametophytic stage of Scytosiphon lomentaria (Lyngbye) Link. The other, a dark crust, resembled the alternate stage of some Scytosiphon species. Comparative analysis of morphology, life history, and DNA sequences strongly suggests that crusts corresponded to sporophytic S. tenellus Kogame and confirm that erect thalli belonged to S. lomentaria. A clear segregation of erect and crustose thalli was found using internal transcribed spacer region 1 and RUBISCO spacer sequences. Furthermore, whereas crusts always grouped with S. tenellus, erect thalli always grouped with S. lomentaria. Life history studies failed to connect the two entities. First, field‐collected S. tenellus produced progeny that either recycled the crust, which reproduced by unilocular zoidangia, or developed into erect thalli. The latter, unlike typical gametophytic S. lomentaria, developed patchy sori of plurilocular zoidangia. Second, S. lomentaria displayed a direct‐type life cycle, in which progeny from erect individuals only developed into erect thalli and produced only plurilocular zoidangia. This constitutes the first experimental study on Scytosiphon from the Pacific coast of South America and the first report of S. tenellus on this coast. It is also the first report of the crustose stage of Scytosiphon appearing as a perennial and dominant algal species in a temperate rocky intertidal system.     

Alien plants in Chile: inferring invasion periods from herbarium records

We used 71,764 specimens (14,988 alien and 56,776 native) from the herbarium CONC at Universidad de Concepción, Chile to identify alien invasion periods. We assumed that the pattern of accumulation of specimens can be used for tracing back the distribution in time of alien species introductions in the Chilean territory. To assess this we constructed Invasion Curves (IC) of native and alien species and specimens recorded in the complete territory and we adapted this methodology to draw Proportion Curves (PC). Increments in the proportion of alien vs. native species can be interpreted as expansions in population size of alien species, either locally or by invasion of new areas. To visualize surface expansions consistent with changes in PC we arranged four maps broadly coincident with inflexions in PC: before 1900, 1940, 1980 and 2004. Invasion curves from both native and alien species produced a first step of positive and rapid increment followed by an extended, apparently stable phase. The first expansion phase of alien flora (1910–1940) coincides with a first period of strong growth of Chilean agriculture as indicated by increments in wheat and other cereals production. A more recent second maximum showed by PC (approximately between 1980 and 2000) occurs in a period when: (i) wheat surface goes down but (ii) wheat production increases, and (iii) forestry exports increases. These changes are coincident with increased mechanization making possible more wheat production in fewer surfaces. The expansions of alien plant species in Chile are evident on geographical distribution maps. In only one century alien species expanded to nearly all the territory. Both the North and South extremes however, seem to be an exception to this general trend as shown by the gaps on maps.     

A modern pollen rain study from the central Andes region of South America

Aim To provide a greater understanding of the modern pollen rain for the central Andes region of South America, thus laying the groundwork for future pollen studies and the derivation of pollen‐climate transfer functions and response surfaces. Location Peru, Bolivia and Chile. Methods Standard palynological techniques for surface soil sampling and discriminant analysis. Results Statistical analysis of the 40 surface samples revealed four palynologically distinct assemblages: (1) the Yungas on the eastern slopes of the Andes; (2) the puna grasslands of the Altiplano; (3) the Coastal Deserts to the west of the Andes; and (4) the Southern Bolivian Highlands. Main conclusions The Yungas group is characterized by high percentages of Urticaceae/Moraceae pollen and fern spores along with trace amounts of pollen from common zoophilous lowland taxa such as Piperaceae, Bignoniaceae and Malpighiaceae. The puna assemblage of the Altiplano is characterized by the dominance of grass (Poaceae) in combination with moderate frequencies of Asteraceae pollen, which tend to increase slightly towards the southern (drier) locations of the Altiplano. Lower percentages of grass pollen and the greater prevalence of Asteraceae, Solanaceae, and the Chenopodiaceae/Amaranthaceae families define the coastal deserts to the west of the Andes. Samples taken from the Southern Bolivian Highlands are characterized by the dominance of Solanaceae in the area, in combination with the pollen of other xerophytic taxa.     

Editorial Board

正2009-2013The World Journal of Biological Chemistry Editorial Board consists of 529 members,representing a team of worldwide experts in biochemistry and molecular biology.They are from 40 countries,including Argentina(1),Australia(7),Austria(2),Belgium(6),Brazil(5),Bulgaria(1),Canada(18),Chile(1),China(36),Czech Republic(1),Denmark     

Growth and development of Calanus chilensis nauplii reared under laboratory conditions: testing the effects of temperature and food resources

We assessed growth and development of naupliar stages of Calanus chilensis Brodsky 1959, under a combination of three temperatures and two food levels in laboratory conditions. Both food supply and temperature significantly affected naupliar growth and development. High food, measured as chlorophyll a (Chl a) concentration, was 40 μg l⁻¹, on average, and yielded temperature-dependent growth rates in the range of 0.13-0.17 day⁻¹. Low food was about 1.2 μg chlorophyll a l⁻¹ and retarded or arrested development and drastically reduced the growth rate to the range of 0.05-0.09 day⁻¹. To test whether these experimental results were consistent with field data, we used published information on temperature and chlorophyll a variability in northern Chile and developed a combined temperature/food-dependent model to diagnose naupliar growth in the field through a 2-year seasonal cycle including the 1997-1998 El Niño conditions. We concluded that in the upwelling region off northern Chile, C. chilensis might seldom encounter conditions of food shortage, as those applied in the laboratory. Thus, naupliar growth of this species may be primarily controlled by environmental temperature and this might also be the case for the dynamics of the entire population inhabiting the coastal upwelling zone.     

The distribution of the ectoparasite fauna of Sebastes capensis from the southern hemisphere does not correspond with zoogeographical provinces of free-living marine animals

Aim We examined the ectoparasite fauna of Sebastes capensis over almost all its geographical distribution range (Chilean, Argentinean and South African coasts) to determine (1) whether the ectoparasites of this host show a zoogeographical pattern and, if so, (2) how this pattern is related to known zoogeographical patterns for free‐living organisms. Location Fish were captured from 20, 24, 30, 33, 36, 40, 45 and 52° S along the Chilean coast; 11° S on the Peruvian coast; 43° S on the Argentina coast; and 34° S on the South African coast. Methods From April to September 2003 and from April to August 2004, 626 fish were captured. The parasites were collected using standard parasitological techniques. At the component community level, zoogeographical distribution patterns were evaluated using cluster analysis. At the infra‐community level, patterns of similarity in parasite composition among localities were investigated with multivariate discriminant analyses. Results The ectoparasite fauna of S. capensis consists of six species distributed along the whole of the Chilean coast. Four other species are distributed only within the transitional zone between the northern warm temperate region (Peruvian faunistic province), extending from Peru to the northern Chilean coast up to c. 30° S, and the cold temperate region (Magellanic faunistic province). The component communities from latitudes 30 to 40° S showed higher ectoparasite species richness, while localities on the margins of the geographical range showed lower species richness. Cluster analysis indicated a grouping of localities consistent with the transitional zone. Argentina and South Africa always emerged as separate localities. Main conclusions The ectoparasite communities of S. capensis do not follow a distributional pattern concordant with the known biogeographical zones for invertebrates and/or fish along the south‐eastern Pacific. Therefore their ectoparasite fauna is not useful as a zoogeographical indicator, although it does allow us to distinguish the transitional zone of the south‐eastern Pacific. On a more extended geographical scale, it is possible to distinguish the ectoparasite communities of S. capensis in the south‐eastern Pacific (as a whole) from those of Argentina and South Africa.     

Growth rates in diameter,basal area,and height of Pilgerodendron uviferum; relationship between growth index and germination

Summary Increment borer samples taken at breast height in Pilgerodendron uviferum (Cupressaceae) trees growing in two Chilean forest stands near latitude 42° south were used to study growth rates in diameter, basal area, and height. Radial average growth is 0.51 mm/year in Santa Luci 0.44 mm/year in the Piuchué stand; the correlation between diameter and age is 0.79 in Santa Lucía and 0.64 in Piuchué. Similar results were obtained in the basal area/age relationship. Both groups of trees have a low rate of growth compared to rates obtained in other studies. Maximum values for radial growth (culmination age) are reached at 110 years of age in Santa Lucia and 50 years in Piuchue. Growth in height, averaging 5.8 cm/year, appears to be similar in all trees analyzed; occasional differences can be attributed to understory position of some trees. Comparison of radial growth and germination of Pilgerodendron plants shows a synchronous relationship, suggesting an influence of climate on the pattern of forest regeneration.     

Pollen grain morphology of Nolana L. (Solanaceae: Nolanoideae: Nolaneae) and related genera of southern South American Solanaceae

Nolana comprises 89 species almost entirely restricted to the Atacama and Peruvian deserts. These species are adapted to the arid lomas environment of northern Chile and southern Peru, where they depend on marine fog locally known as garúa or camanchaca for their development. Recent molecular phylogenetic studies provide support for the placement of Nolana in the Solanaceae rather than Nolanaceae. Additionally, a sister relationship with the tribe Lycieae has been suggested. The pollen morphology of 111 species from 18 genera of southern South American Solanaceae was investigated under light and scanning electron microscopes in order to establish the palynological affinities of Nolana within the Solanaceae and to investigate if pollen morphology is congruent with the phylogenetic relationships and former taxonomic classification of the species of Nolana. The following genera were studied: Nolana, Cestrum, Combera, Dunalia, Fabiana, Jaborosa, Latua, Lycium (incl. Grabowskia, Phrodus), Nicandra, Nicotiana, Nierenbergia, Petunia, Physalis, Reyesia, Salpiglossis, Schizanthus, Solanum and Vestia. Two pollen types that differ in exine structure were distinguished within Nolana; these pollen types are congruent with recent phylogenetic studies, thus, we propose to reinstate Nolana sect. Sorema.     

Cold resistance mechanisms in high desert Andean plants

Freezing tolerance and freezing avoidance were studied, during the growing season, in plant species from two different elevations (3200 m and 3700 m) in a desert region of the high Andes (29° 45S, 69° 59W) in order to determine whether there was a relationship between plant height and cold resistance mechanisms. Freezing injury and supercooling capacity were determined in plants of different height, from ground-level (<20 cm tall) to tall shrubs (27–90 cm). All ground-level plants showed freezing tolerance as the main mechanism for resistance to freezing temperatures. Tall shrubs avoided freezing temperatures, mainly through supercooling. Supercooling was only present in plants occupying the lower elevation (i.e., 3200 m). Both avoidance and tolerance mechanisms are present in a single genus (i.e., Adesmia).     

Cultivation of Gracilaria on the sea-bottom in southern Chile: a review

This review contains information about the cultivation techniques, strategies, problems and new challenges faced as well as an economic analysis of the income-producing capacity of Gracilaria farming, considering the variability of environmental systems where this alga is cultivated in southern Chile. The development of Gracilaria farming in Chile was made possible by an increased market demand, as well as the existence of basic knowledge that permitted the management of wild stocks and the initiation of cultivation practices. Subtidal cultivation systems appear to be more productive than intertidal systems and are less susceptible to wave action than intertidal cultivation areas. In relation to farming practices, this difference implies that planting and harvesting methods and strategies vary between habitats where cultivation is being carried out on a commercial scale. Several problems such as the environmental impact of different cultivation methods adopted by the farmers, the management of contaminating organisms and strain selection appear to be important and new areas for future research. Finally, an analysis of the income-producing capacity indicates that environmental differences also have important consequences for the management strategies of Gracilaria cultivation.