OBSERVATIONS ON CHYTRIDIACEOUS PARASITES OF PHANEROGAMS. XI. A PHYSODERMA ON AGROPYRON REPENS

Sparrow , Frederick K. (U. Michigan, Ann Arbor), Joyce E. Griffin , and Robert M. Johns . Observations on chytridiaceous parasites of phanerogams. XI. A Physoderma on Agropyron repens. Amer. Jour. Bot. 48(9): 850–858. Illus. 1961.—A Physoderma has been found in Michigan on Agropyron repens, which produces dark-brown, non-erumpent streaks up to 20 mm (usually 4–6 mm) in length by 0.5 mm in width and very local discoloration of the leaf blades and sheaths. There is no systemic infection, and plants parasitized are normal in size and bear flowers. Resting spores upon germination produce zoospores which may develop either into the endobiotic, poly-centric, resting spore-bearing thallus or into monocentric, epibiotic, ephemeral sporangia. The latter bear either colorless or orange globuled zoospores. These zoospores may give rise to new epibiotic sporangia, or, apparently without fusing in pairs, to the endobiotic system. Comparison with other congeneric fungi reported on Agropyron repens reveals the Michigan fungus to be distinct from them. Whether it can be embraced within Physoderma graminis (Büsgen) de Wild. or other described taxa on grasses awaits the results of future cross-inoculation studies.     

Screening of diatoms for heterotrophic eicosapentaenoic acid production

Nine strains of diatoms (representing four species) were screened for their ability to produce eicosapentaenoic acid (EPA) when cultured heterotrophically on glucose. Four strains were able to produce EPA heterotrophically using glucose as its carbon and energy source. Of the four,Nitzschia laevis was the best EPA producer, yielding 0.017 g g^–1 dry cell weight.N. laevis was the only species tested which synthesised more EPA heterotrophically than photosynthetically. This study shows thatN. laevis is a potential source of EPA production using heterotrophic culture conditions with glucose as the carbon and energy substrate.Author for correspondence     

Food plants of the Luo of Siaya district,Kenya

Plants used for food by the Luo-speaking people of Siaya District, Kenya, were surveyed as part of a comprehensive ethnobotanical study. Fifty-two crops were observed under cultivation in the district; 69 species are gathered from the wild. Wild fruits, underground portions, leaves, and fungal fruiting bodies are probably important in Siaya as dietary supplements. These non-cultivated resources, particularly important in the driest areas of the district, warrant evaluation for their role as a buffer against periods of food shortage.     

Lucky rugose corals on crinoid stems: unusual examples of subepidermal epizoans from the Devonian of Morocco

Berkowski, B & Klug, C. 2011: Lucky rugose corals on crinoid stems: unusual examples of subepidermal epizoans from the Devonian of Morocco. Lethaia, Vol. 45, pp. 24–33. In the fossil record, evidence for true epizoans, i.e. living animals inhabiting other living host‐animals, is rather rare. A host reaction is usually needed to proof the syn vivo‐settling of the epizoan. Herein, we provide a first report of such an epizoan biocoenosis from various strata of the Early Devonian of Hamar Laghdad, the world‐renowned Moroccan mud‐mound locality. In this case, solitary rugose corals settled as larvae on crinoid stems, perhaps at a spot where the epidermis was missing for some reason (injury, disease). Both the crinoid and the coral began to grow around each other. By doing so, the affected crinoid columnals formed a swelling, where ultimately only an opening slightly larger than the coral orifice remained. We discuss both macroecological and small‐scale synecological aspects of this biocoenosis. The coral profited from its elevated home because it reached into more rapid currents providing the polyp with more food than at the densely populated seafloor, which was probably covered by a coral‐meadow around the mounds and hydrothermal vents. □Corals, crinoids, Early Devonian, epizoans, Morocco, Rugosa.     

Laki-laki (Dennstaedtia glauca,polypodiaceae): A green manure used in traditional andean agriculture

Dennstaedia glauca is used as a green manure in specific agricultural contexts in Puno, Perü. It is applied in conjunction with animal manure and prior to potato cultivation in the first year after a period of fallow. Fronds ofD. glauca, while containing average or low amounts of micronutrients, are high in nitrogen, phosphorus, and potassium in comparison with other fern species and plant material in general. We suggest this fern contributes to fertility of soil used for tuber crops. The plant grows in abundance along watercourses and may play an important role as a recycler of nutrients leached from terraced fields.     

The effect of graded renal nerve stimulation on renal function in the anaesthetized rabbit

The renal nerves of the rabbit were stimulated to cause less than 5, 9 or 22% reduction in renal blood flow. Glomerular filtration rate was reduced by 0, 3 and 11% respectively when the renal nerves were stimulated at these increasing rates. At low and moderate rates of renal nerve stimulation absolute and fractional sodium excretions were reduced by between 17 and 22%, but at the highest rates they were reduced by 55 and 53% respectively. At increasing rates of renal nerve stimulation plasma renin activity was increased by 40, 70 and 180%.