Critical Inuit Studies: An Anthology of Contemporary Arctic Ethnography

Critical Inuit Studies: An Anthology of Contemporary Arctic Ethnography . Pamela Stern and Lisa Stevenson, eds. Lincoln: Nebraska University Press, 2006. 302 pp.     

SOME ASPECTS OF BIG-GAME UTILIZATION OF MINERAL LICKS IN YANKARI GAME RESERVE, NIGERIA

At least ten major mineral licks occur along the Gaji River which bisects the Yankari Game Reserve. The licks show varying degrees of utilization and have craters of up to 1200m³ in volume. Three hundred and eighty five hours of observation were kept at one of the licks. Its use by different species was highly variable. Some species occurring in the reserve made no visits to the lick, whereas Western hartebeest (51 groups), waterbuck (53 groups) and warthog (276 groups) made frequent visits. Lick use was much greater in the daytime than at night, with the peak occurring around 1400 h. A limited number of soil samples (29) were analysed but no single element can be considered as the factor attracting wildlife. However, the lick areas were richer in most minerals than were samples of soil from drier habitat in the open woodland. It is possible that significantly increased lick use might in the future indicate degrading environmental conditions in the drier parts of the reserve. If hides are constructed, the commonly utilized licks will provide excellent opportunities for behaviour observatioii and photography by tourists.     

Somatic Embryogenesis from Clonal Leaf Tissues of Cassava

Leaf lobes were isolated from palmate leaves of clonal cassava(Manihot esculenta Crantz) material growing in vitro or in glasshouseconditions and subjected to a two-stage culture procedure involvingincubation on Murashige and Skoog (MS2) basal medium supplementedwith 2–12 mg l^–1 2,4-D for 20 d (Stage I) beforetransfer to MS2 basal medium supplemented with 0.01 mg l^–12,4-D and 0.1 mg l^–1 6-benzylamino purine (BAP) (StageII medium). Embryogenetic tissues, foliose structures and somatic embryosdeveloped from leaf lobes at all Stage I 2,4-D concentrations,except on those explants isolated from shoot-tip cultures incubatedon MS2 basal medium supplemented with 0.1 mg l^–1 NAA and1.0 mg l^–1 BAP. Leaf lobes isolated directly from glasshouse plants showed optimalembryogenetic competence when subjected to a Stage I cultureperiod of 17 d, although foliose structure initiation was optimalwith shorter Stage I durations. Leaf lobes of 2–4 mm lengthand those isolated from phyllotaxic leaf numbers 4 and 5 showedthe greatest embryogenetic competence. Manihot esculenta, cassava, somatic embryogenesis, tissue culture, morphogenetic competence     

Studies on the Growth in Culture of Plant Cells: I. GROWTH PATTERNS IN BATCH PROPAGATED SUSPENSION CULTURES

Techniques are described for following increases in total cellnumber, fresh weight and dry weight, and changes in mean cellsize, and in the relative number of free cells to cell aggregatesduring the growth of batch-propagated suspension cultures oftissues derived from several species of angiosperms. When totalcell number is plotted against time it is seen that there canbe distinguished in sequence a lag phase, phases of acceleration,maximum rate, and negative acceleration of cell division and,finaly, a stationary phase. Studies with Parthenocissus tricuspidatacrown-gall tissue, growing in a synthetic liquid medium, haveshown that the total cell production per culture in the firstinstance is limited by nitrate supply rather than by the supplyof other inorganic ions, sucrose supply aeration, or the releaseof endogenous inhibibors. Studies, particularly with Acer pseudoplatanustissue, have shown that during the period of high cell-divisionrate, mean cell size reached its minimum value and average numberof cells per cell aggregate its maximum value. Cell separationdoes not occur to a significant extent until cell-division activityhas almost ceased and it is dependent upon cell expansion. Thebalance between cell division and cell expansion determinesthe ‘cellular unit’ composition of the cultures.Refinement of the control of growth patterns in plant suspensioncultures calls for further study of the ‘conditioning’of media, of factors which limit the duration of the periodof high mitotic activity, and of the conditions necessary forfull and rapid cell expansion.     

Structural Observations on the Growth of Potato Shoot-tip Cultures after Thawing from Liquid Nitrogen

High levels of plantlet regeneration can be achieved from shoot-tipcultures of the Andean potato Solanum goniocalyx thawed fromliquid nitrogen. A rapid rate of cooling and the presence ofdimethyl sulphoxide as a cryoprotectant appear to be necessary.Microscopical examination of surviving shoot-tip cultures showsthem to contain considerable numbers of damaged cells afterthawing. Structural aspects of this damage have been detailedusing transmission electron microscopy. The presence of a numberof such damaged cells in a surviving, thawed shoot-tip neednot prevent its subsequent organised growth directly into acultured plantlet. Solanum goniocalyx, potato, shoot-tip cultures, cryopreservation, plantlet regeneration     

Notes on habitat relationships of ungulates in Yankari Game Reserve, Nigeria

Yankari Game Reserve in northeastern Nigeria consists largely of savanna woodland with trees on the better soils growing to 15 m and with spreading crowns. On shallow and stony soils the tree height is generally less and the canopy is discontinuous. The Gaji River riparian zone supports a wide variety of vegetation types ranging from evergreen, closed canopy forest to sedge meadows and patches of open grassland.
Elephant ( Loxodonta africana ) range backwards and forwards along the riparian strip, feeding on perennial grasses and a variety of browse material and utilizing closed canopy forest patches for shade cover. The major movement patterns of other important herbivore species are perpendicular to the riparian strip. Areas used intensively are: waterbuck ( Kobus defassa )–open savanna woodland immediately behind the riparian strip: Western hartebeest ( Alcelaphus buselaphus major )– open grassy habitat in relatively poor woodland at middle distances from the river; Roan antelope ( Hippotragus equinus )–patches of well-developed and infrequently burned woodland, often at major distances from the river. Buffalo ( Syncerus caffer brachyceros ) during the dry season ranged between the riparian grassland areas and the more open sections of nearby savanna woodland, but travelled out to distant sections of the reserve after rainwater pools had formed.
A major problem in management was the development of a burning policy that would maintain an appropriate balance between perennial and annual grasses and the shade providing trees.     

The Regulation of Synthesis of Phenolics in Stationary Phase Cell Cultures of Acer pseudoplatanus L.

The addition of 2/ (w/v) sucrose to stationary phase suspensioncultures of sycamore (Acer pesudoplatanus) in medium depletedof nitrogen and phosphorus leads to the accumulation of highlevels of phenolics after a 5 d lag period. Urea and 2,4-D inhibitthis accumulation of phenolics. Urea results in a stimulationin cell protein content coincident with phenolics in hibition,and leads to a substantial diversion of the common precursorphenylalanine from phenolics synthesis into protein synthesis.2,4-Dichlorophenoxyacetic acid (2,4-D) does not lead to proteinaccumulation since the cultures are nitrogen-limited, but stimulatesan increase in protein turnover coincident with phenolics inhibition.The role of protein synthesis in the regulation of phenolicsmetabolism through competition for common precursors is discussed.     

Organization and Alkaloid Production in Tissue Cultures of Hyoscyamus niger

Callus and cell suspension cultures were established from Hyoscyamusniger seedlings and their growth requirements investigated.Stock suspensions were more aggregated in the earlier passagesbut became finer as the cultures were serially sub-cultured.On transfer to auxin-free medium, the cultures formed rootsand shoots were rarely noted. Callus initiated from differentparts of the seedlings showed no differences in alkaloid levels.Alkaloid contents were slightly increased on transfer to auxin-freemedium. Both alkaloid content and composition changed duringserial propagation. Different parts of the intact plant werealso analysed for alkaloids.