Relationship of soil moisture, temperature and alkalinity to a soybean nodulation failure

The roles of low soil moisture, high soil temperature and soil alkalinity in a soybean nodulation failure in an alkaline black soil were assessed. It is concluded that soil temperatures, although not the main cause, could lead to nodulation failure when coupled with soil alkalinity influences. Rhizobium strain selection in the field, higher inoculum levels and seed pelleting were the most promising approaches to its solution

Nodulation and nitrogen fixation in some Desmodium species

Effective nodulation of Desmodium uncinatum was obtained by inoculation with Rhizobium isolated from D. intortum and Glycine javanica, but no nodules were formed with isolates from Glycine tabacina, Stylosanthes humilis, Arachis hypogaea or Lespedeza striata. Three reputedly highly efficient strains of Rhizobium on Desmodium were tested for nitrogen fixation in five species of Desmodium. The host spectrum of effective association varied

Effect of nitrification of a black earth soil on legume nodulation

Black soil from the Darling Downs, Queensland, nitrified to 130-159 p.p.m. nitrate nitrogen in the glasshouse when subjected to 8 cycles of wetting and air-drying. The highest level in the field was 43 p.p.m. nitrate nitrogen. Nodulation inhibition in soybeans by nitrate and ammonium ions was compared. The nitrate ion was more active and nitrate levels close to 168 p.p.m. N were necessary to prevent nodulation, while ammonium ions as high as 224 p.p.m. N were only partly inhibitory. Interplanting soybean with sorghum in the field reduced the nitrate levels in the vicinity of the legume but did not overcome a nodulation failure from inoculated seed. Nitrate inhibition is an unlikely explanation for soybean nodulation failures on black soils

Effects of soil moisture on the success of soil-applied inocula for soybeans

A field trial was carried out on three sites on black soil comparing seed inoculation of soybeans with soil application of inoculum. Inoculum was applied into the furrow as a peat inoculum in a water suspension at three levels of application (80, 250, 500 l ha-1) or carried on treated alkythene granules. The soil moisture at planting varied between sites. Seed inoculation gave a consistently high level of nodulated plants (c. 70%) and treated alkythene granules consistently low (c. 50%) at all sites. Nodulation results from the water suspension depended on the level of water applied and the planting moisture. At the low moisture site only high volume application (500 l ha-1) produced satisfactory nodulation of 63%. Evidently, the tolerance of peat cultures to moisture stress is reduced by suspension in water before application to soil. The efficiency of the solid inoculant method could probably be improved by increasing the number of inoculum loci through decreased granule size

Effective natural nodulation of peanuts in Queensland

In field experilnents, peanuts nodulated naturally in both a scrub and a forest soil at Kingaroy. Seed and soil inoculations were attempted, but it was difficult to superimpose the inoculum strain on the existing soil rhizobial population. There was a yield response to some inoculation treatments on new land with lower rhizobial count but not on land cropped previously to peanuts. Glasshouse tests confirmedthat the majority of field isolates of peanut rhizobia were effective in nitrogen fixation. Natural transfer of rhizobia on seed was recorded. It was concluded that inoculation of peanuts was unlikely to be adopted in this peanut growing district

Failure of navy beans to respond to inoculation with Rhizobium

Three field experiments were conducted at four sites to select a suitable strain of Rhizobium and to gauge the response of navy beans to inoculation with Rhizobium and to ammonium nitrate. Of the seven plantings, only two had satisfactory nodulation despite the presence of effective naturalized rhizobia at all sites. Where nodulation was poor, there were no growth responses to ammonium nitrate. Soil moisture and nitrate levels seem to be implicated in the nodulation failure

Type 2 Diabetes: Hypoinsulinism, Hyperinsulinism, or Both?

The author discusses a new study reporting the birth weight of patients carrying a mutation in either of two closely related genes associated with maturity-onset diabetes of the young, testing the hypothesis that the primary defect caused by these genes results in decreased insulin secretion

Root-targeted biotechnology to mediate hormonal signaling and improve crop stress tolerance

peer reviewe

Wolcott-Rallison Syndrome

Wolcott-Rallison syndrome (WRS) is a rare autosomal-recessive disorder characterized by the association of permanent neonatal or early-infancy insulin-dependent diabetes, multiple epiphyseal dysplasia and growth retardation, and other variable multisystemic clinical manifestations. Based on genetic studies of two inbred families, we previously identified the gene responsible for this disorder as EIF2AK3, the pancreatic eukaryotic initiation factor 2α (eIF2α) kinase. Here, we have studied 12 families with WRS, totalling 18 cases. With the exception of one case, all patients carried EIF2AK3 mutations resulting in truncated or missense versions of the protein. Exclusion of EIF2AK3 mutations in the one patient case was confirmed by both linkage and sequence data. The activities of missense versions of EIF2AK3 were characterized in vivo and in vitro and found to have a complete lack of activity in four mutant proteins and residual kinase activity in one. Remarkably, the onset of diabetes was relatively late (30 months) in the patient expressing the partially defective EIF2AK3 mutant and in the patient with no EIF2AK3 involvement (18 months) compared with other patients (<6 months). The patient with no EIF2AK3 involvement did not have any of the other variable clinical manifestations associated with WRS, which supports the idea that the genetic heterogeneity between this variant form of WRS and EIF2AK3 WRS correlates with some clinical heterogeneity