Control of potato cyst-nematode, Heterodera rostochiensis, in sandy, peaty and silt loam soils by dazomet and Telone applied in different ways

Dazomet applied in the ridges in autumn or in spring, before potatoes were planted in them, controlled potato cyst-nematode (Heterodera rostochiensis), British pathotype A, better in sandy loam and peaty loam than Telone (1,3-dichloropropene mixture). In sandy loam dazomet controlled potato cyst-nematode as well when applied in spring as when applied in autumn and as well when the soil was ridged after treatment as when it was not. Telone was as effective when applied to ridges in autumn as when applied to ridges in spring. In peaty loam potato cyst-nematodes were least abundant after a crop of Maris Piper potatoes. The yields of King Edward potatoes were greatly increased and nematode multiplication was greatly reduced by dazomet incorporated in the ridges in autumn. Two equal doses of dazomet, one incorporated in the topsoil before, the other after ploughing, controlled potato cyst-nematode as well and increased the yield of King Edward potatoes more than an equivalent amount of dazomet applied after ploughing. Dazomet applied to silt loam soil in two dressings, one before, the other after, ploughing, controlled potato cyst-nematode better than an equal amount applied as a single dressing after ploughing. The nematode was controlled best by two large dressings of dazomet or by a combined treatment of dazomet and Telone.     

Recovery from clearing,cyclone and fire in rain forests of Tonga,South Pacific: Vegetation dynamics 1995–2005

Abstract In late 2001 a category 3 cyclone impacted forest plots that were established in Tonga in 1995, and additionally, one plot was accidentally burned by an escaped land‐clearing fire. Subsequent surveys provide observations of 10 years of forest dynamics in this poorly studied region, and the first reported observations of large interannual variation in juvenile (seedling and sapling) abundance in the western tropical Pacific. The severely disturbed (burned) plot was initially colonized by a non‐native early pioneer, Carica papaya L., but 3.5 years later a native pioneer, Macaranga harveyana (Muell. Arg.) Muell. Arg., was the most abundant tree species. The seedling layer included some long‐lived pioneers and shade‐tolerant species. Two mature forest plots affected only by the cyclone changed very little over a decade. Late‐successional shade‐tolerant species that dominated the overstory were also abundant as seedlings and saplings. This is in contrast with a 30‐ to 40‐year‐old, formerly cultivated, secondary forest plot that still shows no recruitment of late‐successional dominants, in spite of the proximity of remnant forest patches. This study suggests differing pathways of succession following shifting cultivation versus cyclone and fire disturbances in Tonga. Land use legacies appear to have a long‐lasting effect on community composition.     

Development of N2-fixing nodules on the wetland legume Lotus uliginosus exposed to conditions of flooding

Seeds of the wetland legume, Lotus uliginosus , were germinated and grown in vermiculite which was either continuously flooded or well-drained. Plants from both treatments were infected by Mesorhizobium loti strain DUS341 via a 'classical' root hair pathway, although some flooded plants appeared to be infected via enlarged epidermal cells. Subsequent to infection by M. loti , nodule meristems, which had developed within the root outer cortex, were penetrated by infection threads that released bacteria into the meristematic cells. The infection threads and infection droplets were immunogold labelled with monoclonal antibodies (MAC265 and MAC236) that recognize epitopes (at approx. 155/170 and 170/210 kDa, respectively) on a glycoprotein component of the matrix that surrounded the bacteria within the threads or droplets. Although labelling of infection threads or infection droplets with MAC236 was stronger than that with MAC265, both antibodies strongly labelled material occluding intercellular spaces in the cortices of developing nodules that had not yet expressed nitrogenase (as determined by a lack of signal after immunogold labelling with an antibody raised against nitrogenase component II). After 60 d, nitrogenase activity, shoot and root dry weights, and nodule fresh weight per plant did not differ between the treatments. After a further 30 d submergence, the flooded stems developed extensive aerenchyma and there was profuse development of (nodulated) adventitious roots. Nodules also formed at the junction of adventitious roots and the subtending stem and these were connected vascularly to a small stalk of tissue which gave rise to both a nodule and an adventitious root. The flooded nodules had prominent lenticels, and possible air pathways from the atmosphere to the nitrogen-fixing bacteroids are discussed.     

Reconstruction of Laser-scanned 3D Torso Topography and Stereoradiographical Spine and Rib-cage Geometry in Scoliosis

Assessments of scoliosis are routinely done by means of clinical examination and full spinal x-rays. Multiple exposure to ionization radiation, however, can be hazardous to the child and is costly. Here, we explain the use of a noninvasive imaging technique, based on laser optical scanning, for quantifying the three-dimensional (3D) trunk surface topography that can be used to estimate parameters of 3D deformity of the spine. The laser optical scanning system consisted of four BIRIS laser cameras mounted on a ring moving along a vertical axis, producing a topographical mapping of the entire torso. In conjunction with the laser scans, an accurate 3D reconstruction of the spine and rib cage were developed from the digitized x-ray images. Results from 14 scoliotic patients are reported. The digitized surfaces provided the foundation data to start studying concordance of trunk surface asymmetry and spinal shape in idiopathic scoliosis.     

Further studies on the evolution of land and freshwater nemerteans: generic relationships among the paramonostiliferous taxa

The costs and benefits of fighting in bovids are high in terms of injury and reproductive success, respectively. The breakage of a horn would curtail reproductive success permanently. Therefore, the horns of bovids should include sufficient material so that they are strong enough to be unlikely to break in fighting but without being too heavy to carry around. The forces developed during fighting were measured in a computerized analysis of film of blackbuck and bighorn sheep. All possible modes of failure were investigated using a mechanical analysis to see how the horns are most likely to fail.
The maximum possible force developed during fighting is 3400 N for the bighorn sheep and 456 N for the blackbuck. Bending stress, shear stress, deflection, strain energy and critical crack lengths were calculated for the horns of these two bovids. Horns are most likely to fail in bending as indicated by safety factors. Most of the force is taken in compression due to the curvature of horns. Shear stresses are insignificant and deflections are negligible during the most forceful encounters.
The safety factor in bending of the horn of the bighorn sheep is greater (10) than that of the horn of the blackbuck (3.4) because the forces are probably more variable and unpredictable in the fighting of the former.
All of the energy of fighting is absorbed by the body musculature because horns store less than 1% of the energy produced in fighting as strain energy when they bend. Cracks and scratches mustbe more than 60% of the transverse basal dimensions of horns in order for there to be catastrophic failure at the maximum stresses developed during fighting.
The horns of the blackbuck and the bighorn sheep appear to be minimum weight structures given the variability of the forces acting on them and are unlikely to break in fighting given the forces calculated from the analyses of films.     

USE OR REFUSE REPRODUCTIVE GENETIC TECHNOLOGIES: WHICH WOULD A ‘GOOD PARENT’ DO?

A number of authors have objected to potential parents' use of reproductive genetic technologies on the grounds that the use of these technologies reflects a morally problematic attitude toward parenting. More specifically, proponents of this view have argued that such a choice is inconsistent with the unconditional acceptance that lies at the heart of praiseworthy parental attitudes. This paper offers a rebuttal of this view by arguing that it is possible for a parent to exhibit unconditional acceptance of the child herself without accepting each of that child's traits. If this is true, the use of reproductive genetic technologies does not inherently undermine appropriate parental attitudes. Further, by working to change some of a child's specific traits, a parent may instead exemplify an aspirational aspect of praiseworthy parenting and so demonstrate appropriate parental attitudes.     

Effects of potato genotype, oxamyl and the numbers of potato cyst-nematodes, Globodera rostochiensis or G. pallida on tuber yields and nematode increase

A new technique is described for establishing different numbers of the potato cyst-nematode Globodera rostochiensis in field soil, which leaves the soil homogeneous in nutrient status. Field plots established in this way were used to compare yield losses in four potato cultivars (Maris Piper, Pentland Crown, Pentland Dell and Désirée) associated with different numbers of G. rostochiensis. Over the range of 7.4 to 148.4 eggs g^-1 soil at planting, yield losses were 18.7% (Maris Piper), 53.2% (Désirée), 55.7% (Pentland Crown) and 63.5% (Pentland Dell). Similar results were obtained in another experiment on the same field in a different year using only lightly and heavily infested plots. Treating the seedbed soil with oxamyl before planting prevented significant injury to potatoes by G. rostochiensis but increased the yield of Pentland Dell and perhaps Désirée (but not Maris Piper or Pentland Crown) more than expected from nematode control alone. Treating heavily infested soil with such a nematicide cannot therefore be recommended as part of a valid procedure for establishing lightly and heavily infested plots for comparing tolerances of attack by potato cyst-nematodes in a range of potato genotypes. In peaty loam soils moderately or heavily infested with G. pallida, oxamyl at 5.6 kg a.i. ha^-1 incorporated into the seedbed before potatoes were planted generally increased tuber yields, though the effects varied considerably with the cultivar grown. Increase of G. pallida in these soils was controlled better by growing potatoes bred for resistance to it (ZB 35 – 29, Caxton, Santé, Morag, 11233 ab 22, Fingal, A27/23, Cromwell). Increase of G. pallida on susceptible cultivars varied greatly and Romano increased G. pallida no more than the resistant Morag. G. pallida is probably controlled best in peaty loam by growing a resistant cultivar in soil treated with a granular (non-fumigant) nematicide.     

Stem canker (Rhizoctonia solani) on five early and seven maincrop potato cultivars I. Infection of shoots, stolons and tubers

In 1983 and 1984, potato seed tubers of five early and seven maincrop cultivars were inoculated with cultures of Rhizoctonia soluni during planting to simulate severe seed infection. Shoot and stolon infection was assessed in June-August and black scurf on tubers recorded after harvest in October. Almost all shoots of all cultivars had stem canker in both years and disease on shoots, stolons and tubers was more severe in 1984 than in 1983. In 1983 similar amounts of disease developed on all early cultivars and between 11% (Ulster Sceptre) and 32% (Maris Peer) shoots were pruned off. Maris Peer had a stem canker score lower than other cultivars in 1984 but more than half the shoots were pruned off. Shoot pruning on Estima, Ulster Prince and Ulster Sceptre was more common on plants from sprouted than non-sprouted seed. Between 30 and 50% of stolons were pruned off. After harvest in 1985, black scurf was least prevalent on Arran Comet and Maris Peer tubers and in 1984 on Arran Comet and Estima tubers from non-sprouted seed. Of the maincrop cultivars, King Edward plants from sprouted seed had many shoots pruned off in both years. Shoot pruning was also prevalent on Maris Piper and Pentland Squire plants from non-sprouted seed. Record had fewest pruned shoots and stolons and the lowest stem canker score. The disease was more severe on Pentland Crown and Maris Piper plants from non-sprouted than sprouted seed. Black scurf was most common on Cara and King Edward tubers in 1983 and on King Edward and Record tubers in 1984. In both years few shoots but many tubers were infected on plants from non-inoculated seed and the significance of this is discussed.     

Comparison of measured and EF5-r-derived N2O fluxes from a spring-fed river

There is considerable uncertainty in the estimates of indirect N₂O emissions as defined by the intergovernmental panel on climate change's (IPCC) methodology. Direct measurements of N₂O yields and fluxes in aquatic river environments are sparse and more data are required to determine the role that rivers play in the global N₂O budget. The objectives of this research were to measure the N₂O fluxes from a spring‐fed river, relate these fluxes to the dissolved N₂O concentrations and NO₃‐N loading of the river, and to try and define the indirect emission factor (EF5‐r) for the river. Gas bubble ebullition was observed at the river source with bubbles containing 7.9 μL N₂O L^?1. River NO₃‐N and dissolved N₂O concentrations ranged from 2.5 to 5.3 mg L^?1 and 0.4 to 1.9 μg N₂O‐N L^?1, respectively, with N₂O saturation reaching 404%. Floating headspace chambers were used to sample N₂O fluxes. N₂O‐N fluxes were significantly related to dissolved N₂O‐N concentrations (r²=30.6) but not to NO₃‐N concentrations. The N₂O‐N fluxes ranged from 38–501 μg m^?2 h^?1, averaging 171 μg m^?2 h^?1 (±SD 85) overall. The measured N₂O‐N fluxes equated to an EF5‐r of only 6.6% of that calculated using the IPCC methodology, and this itself was considered to be an overestimate because of the degassing of antecedent dissolved N₂O present in the groundwater that fed the river.