Characterization of Rice (Oryza sativa L.) Roots Versus Root Pulling Resistance as Selection Indices for Draught Tolerance

A technique described as Root Pulling Resistance (RPR) was used to evaluate genotypic differences in root growth and development of 50 rice germplasm accessions and cultivars. Several root characteristics in rice are associated with drought tolerance and avoidance capability of plants. The RPR measurements showed a significant positive correlation with maximum root length (r=0.69), root thickness (r=0.75), branching number (r=0.75), and root dry weight (r= 0.82). Rice genotypes that had a high RPR value were identified as having longer, thicker, and denser root systems. The data indicated that high RPR measurements are strongly correlated with greater root penetration. Munji Sufaid Pak, IR52 (IR5853-1 18-5) and Saunfia or Mabla Pak 329 had a significantly greater root length, root thickness, root number, root branching and dry weight as compared to IR 36. Also, there was no correlation between plant height and RPR. Furthermore, the data demonstrated that the RPR technique is ideal for selecting superior root systems and potential drought tolerant rice germplasm and cultivars

Screening Rice (Oryza Sativa L.) Genotypes for Drought Tolerance Under Field Conditions

We evaluated the root pulling resistance (RPR) technique developed at the International Rice Research Institute (IRRI) for transplanted rice (Oryza sativa L.) to determine its applicability for assessing the drought tolerance of direct seeded rice. Experiments were conducted in 1988 and 1989 at the University of Arkansas at Pine Bluff Agricultural Research Farm. Fifty genotypes from four countries were grown with and without irrigation. The genotypes identified as drought tolerant germplasm by the RPR method in both years were significantly correlated. In both 1988 and 1 989, RPR was directly related to maximum root length, root number, and root dry weight. Root dry weight (RWT) had the highest correlation with RPR in both 1988 (r= 0.82 ** ) and 1989 (r=0.46 * * ). Cultivars with the greatest root lengths and root dry weights had the highest root pulling resistances

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Fractional order analysis of Sephadex gel structures: NMR measurements reflecting anomalous diffusion

We report the appearance of anomalous water diffusion in hydrophilic Sephadex gels observed using pulse field gradient (PFG) nuclear magnetic resonance (NMR). The NMR diffusion data was collected using a Varian 14.1 Tesla imaging system with a home-built RF saddle coil. A fractional order analysis of the data was used to characterize heterogeneity in the gels for the dynamics of water diffusion in this restricted environment. Several recent studies of anomalous diffusion have used the stretched exponential function to model the decay of the NMR signal, i.e., exp[−(bD)(α)], where D is the apparent diffusion constant, b is determined the experimental conditions (gradient pulse separation, durations and strength), and α is a measure of structural complexity. In this work, we consider a different case where the spatial Laplacian in the Bloch-Torrey equation is generalized to a fractional order model of diffusivity via a complexity parameter, β, a space constant, μ, and a diffusion coefficient, D. This treatment reverts to the classical result for the integer order case. The fractional order decay model was fit to the diffusion-weighted signal attenuation for a range of b-values (0 < b < 4,000 s-mm(−2)). Throughout this range of b values, the parameters β, μ and D, were found to correlate with the porosity and tortuosity of the gel structure