The nematode Goezia spinulosa (Diesing, 1839) (Raphidascarididae) is redescribed based on specimens found in the stomach and intestine of the naturally infected arapaima Arapaima gigas (Schinz) from the Mexiana Island, Amazon River Delta, Brazil. Light and electron microscopy examinations revealed some previously unreported or inaccurately described morphological features in the species, such as the position of the excretory pore, phasmids in the male or the number (4) of postanal papillae. The morphology of G. spinulosa is compared with that of other four congeneric species parasitizing freshwater fishes in South America. This nematode seems to be one of the most pathogenic parasites of A. gigas in the Mexiana Island, which are responsible for a high mortality of cultured arapaima fingerlings. Apparently, the source of G. spinulosa infection for arapaima fingerlings cultured in tanks was the infected plankton collected in the localities inhabited by wild arapaimas. Therefore, control measures should include the sterilisation of the plankton before its use as food for fish. A rare infection of Eustrongylides sp. larvae (Dioctophymatidae) in arapaima fingerlings was also found (new host record); the larvae were inside swellings on the body surface.
So called small basins were originally specified with the aim to obtain more accurate data about the hydrological and hydrometeorological regimes of an extensive region. Later on the attention was also paid to the monitoring of chemical components and geochemical processes. Gradually it was discovered that small basins can also supply valuable information about the ecological stability and social and economic processes in relation to the ethnic features and local history of the studied region. Obviously, a decision about the size of small basins should be adapted to the nature of solved problems and with respect to the size of the region under consideration. A proposal how to define a small basin is presented as one of the conclusions. and Malá povodí byla původně zakládána s cílem získat zpřesněná data o hydrologickém a hydrometeorologickém režimu v rámci širšího regionu. Později se pozornost soustředila i na sledování chemismu a geochemických procesů. Postupně se ukázalo, že povodí poskytují další významné informace o ekologické stabilitě, a o procesech sociálních a ekonomických ve vztahu k etnickému složení populace; také o místní historii. Rozhodování o velikosti povodí je postupně podřizováno povaze řešených úloh a lze je posuzovat především ve vztahu k velikosti povodí, pro něž se informace získávají. Proto je návrh možné definice malého povodí uveden až v samém závěru tohoto příspěvku. V následujícím příspěvku jsou diskutovány některé typické úlohy, při jejichž řešení se významně uplatnily různé informace získané z malých povodí.
We assessed the effect of the exposure to full sunlight (5, 35, and 120 min, i.e. T5, T35, and T120) on fluorescence parameters of two young tropical trees, Swietenia macrophylla, a gap-demanding species, and Minquartia guianensis, a shade tolerant species. Fluorescence parameters (F0, Fm, Fv/Fm) were recorded before treatments and after the transition to low irradiance (LI). Recovery from photoinhibition (measured as Fv/Fm) was monitored for 24 h at LI. In Swietenia, an almost complete restoration of the Fv/Fm values occurred in T5 and T35 plants, when a rise in F0 was observed after the transition to LI. This was inferred as indicative of dynamic photoinhibition. T120 led to a decline in F0 in Minquartia, but not in Swietenia. The plants of both species were unable to recovery from photoinhibition after 24 h at LI, when F0 declined or remained unchanged. This was interpreted as indicative of chronic photoinhibition. Compared with Swietenia, Minquartia was more susceptible to photoinhibition, as indicated by lower Fv/Fm values. and D. P. Dias, R. A. Marenco.
In Ochroma pyramidale (Cav. ex Lam.) Urb., photon-saturated photosynthetic capacity (PNmax) was 13 μmol(CO2) m-2 s-1. Average stomatal conductance (gs) and water-use efficiency (WUE) were greater at high irradiance, about 260 mmol(H2O) m-2 s-1 and 2.15 g(C) kg-1(H2O), respectively. In the dark, gs values were about 30% of maximum gs. Leaf nutrient contents on a leaf area basis were 131, 15, 36, 21, and 12 mmol m-2 for N, P, K, Ca, and Mg, respectively. Ochroma also accumulated a greater amount of soluble saccharides than starch, 128 versus 90 g kg-1 (DM). The availability of N and Mg, but not P, Ca, or K, may limit photosynthetic rates of Ochroma in this site. and R. A. Marenco, J. F. de C. Gonçalves, G. Vieira.