Screening eucalypts for frost tolerance in breeding programs

1992 ◽  
Vol 22 (9) ◽  
pp. 1271-1277 ◽  
Author(s):  
C.A. Raymond ◽  
J.V. Owen ◽  
K.G. Eldridge ◽  
C.E. Harwood
Keyword(s):  
Data Analysis ◽  
Genetic Selection ◽  
Leaf Tissue ◽  
Frost Tolerance ◽  
Leaf Damage ◽  
Alternative Methods ◽  
Small Samples ◽  
Leaf Discs ◽  
Relative Conductivity ◽  
Highly Correlated

Improvements in a laboratory technique and statistical methods for screening eucalypts for relative frost tolerance using small samples of leaf tissue are described. As a contribution to more efficient genetic selection in a breeding program, these methods aim to provide reliable estimates of relative frost tolerance for ranking genotypes and to allow partitioning of total variation into components due to provenances, families, and individuals. Examination of sampling strategies indicated that four leaf discs per seedling at three frosting temperatures and 10 seedlings per family provided highly reliable estimates of frost tolerance. Mean relative conductivity values were found to be highly correlated with mean leaf damage sustained by a seedling across the whole range of values. Alternative methods of data analysis are compared. Estimation of LD50 values (the temperature at which 50% of leaf discs would be killed) and calculation of percent survival of leaf discs were found to be less efficient means of data analysis than directly analysing relative conductivity values. The nature of genetic control of frost tolerance and the assumptions underlying such nondestructive screening techniques are examined.

A Conductivity Method for Screening Populations of Eucalypts for Frost Damage and Frost Tolerance

1986 ◽  
Vol 34 (4) ◽  
pp. 377 ◽  
Author(s):  
CA Raymond ◽  
CE Harwood ◽  
JV Owen
Keyword(s):  
Leaf Disc ◽  
Leaf Tissue ◽  
Conductivity Measurement ◽  
Frost Damage ◽  
Field Trials ◽  
Frost Tolerance ◽  
Leaf Damage ◽  
Conductivity Method ◽  
Survival Status ◽  
Whole Plant

The assessment of frost tolerance of Eucalyptus leaf tissue by an electrical conductivity method is described. Leaf disc samples were exposed to freezing treatments in test tubes within a liquid cold bath with precise temperature control, and the conductivity of the disc leachate measured. Leaf discs were then frozen at -20°C to obtain an absolute conductivity for the tissue. A modified relative conductivity value (RC*) is presented together with calibration against visual observations of leaf damage for seedlings of E. regnans and E. delegatensis. RC* was found to be a reliable indicator of leaf survival status and the RC*-damage relationship was constant across provenances of both species. Provenance and family variation for frost tolerance were examined for both species and significant differences in tolerance levels were found for unhardened E. delegatensis and for hardened seedlings of both species at several test temperatures. Provenance rankings were identical to results from field trials reported in the literature. The effect of the period between frost treatment and conductivity measurement was assessed together with variation between leaves of the same plant and the effect of storage of cut leaves for 24 h prior to exposure to frosting treatments. The absence of any significant effects from storing leaves for 24 h indicates the potential of using the method to screen samples collected in the field. Problems of relating RC*, leaf damage and survival of the whole plant are discussed and the potential use of RC* as a simple screening technique for identifying frost-tolerant families and provenances is examined.

An Optimised Data Analysis for the Balb/c3T3 Cell Transformation Assay and its Application to Metal Compounds

2007 ◽  
Vol 20 (4) ◽  
pp. 673-684 ◽  
Author(s):  
J. Ponti ◽  
B. Munaro ◽  
M. Fischbach ◽  
S. Hoffmann ◽  
E. Sabbioni
Keyword(s):  
Data Analysis ◽  
Cell Transformation ◽  
T Test ◽  
Alternative Methods ◽  
Metal Compounds ◽  
Exact Test ◽  
Fisher's Exact Test ◽  
Transformation Assay ◽  
Carcinogenic Potential ◽  
Fisher’S Exact Test

The Balb/c3T3 cell transformation assay (CTA) is an available in vitro system to detect the carcinogenic potential of chemicals. Currently, the European Centre for the Validation of Alternative Methods (ECVAM) is validating this test, assessing its reliability and relevance. Its endpoint is the formation of type III foci, which is, when using clone A31-1-1, a very rare event that usually does not occur at all for negative controls. The carcinogenic potential of a compound tested is assessed by comparing the number of foci in treated and untreated cells. The objective of the present work is to optimise the data analysis for this endpoint by applying the most commonly used approach by a t-test and the Fisher's exact test as an alternative approach. For this purpose selected metal compounds classified as carcinogenic (NaAsO2, CdCl2 cisPt), as suspected carcinogenic (C6H5)4AsCl, CH3HgCl), or as compounds without evidence of carcinogenic properties in humans ((NH4)2PtCl6, NaVO3) as well as a non-carcinogenic (AgNO3) were analysed. Our evaluation revealed that the t-test approach, which assumes normality of data, is not appropriate. The results demonstrated that the statistical analysis by Fisher's exact test better reflects the data properties and greatly facilitates the interpretation of Balb/c3T3 CTA data regarding carcinogenic potential.

Metabolic Detoxification of Phenmedipham in Leaf Tissue of Tolerant and Susceptible Species

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 206-214 ◽  
Author(s):  
H. Maelor Davies ◽  
Alexis Merydith ◽  
Liane Mende-Mueller ◽  
Alpo Aapola
Keyword(s):  
Oxygen Evolution ◽  
Leaf Tissue ◽  
The Other ◽  
Leaf Discs ◽  
Metabolic Detoxification

Phenmedipham metabolism in leaf tissue of sugarbeet (tolerant) and rapeseed (sensitive) was compared. Sugarbeet leaf discs metabolized phenmedipham much more rapidly than rapeseed leaf discs, forming two metabolites of relatively low polarity. The less polar of these (metabolite 21) was a precursor to the other (metabolite 11), and its properties indicate derivation from phenmedipham by a single hydroxylation and monoglycosylation. Synthetic N-hydroxyphenmedipham was converted by both species into a compound that cochromatographs with metabolite 21. Purified metabolite 21 was much less inhibitory to light-driven oxygen evolution by isolated thylakoids of both species than was phenmedipham. Hydroxylation/glycosylation without prior carbamate hydrolysis appears to be a major factor in the tolerance of sugarbeet to phenmedipham.

scholarly journals Development and Operation of the Harwell Small Counter Facility for the Measurement of 14C in Very Small Samples

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 565-575 ◽  
Author(s):  
R L Otlet ◽  
George Huxtable ◽  
G V Evans ◽  
D G Humphreys ◽  
T D Short ◽  
...  
Keyword(s):  
Data Analysis ◽  
Data Capture ◽  
Small Samples ◽  
Chemical Processing ◽  
Long Acting ◽  
Shield Design

The Harwell system for measuring milligram size samples using Brookhaven miniature gas counters is fully operative. It comprises 12 counters of different sizes which operate simultaneously within a single NaI crystal (300mm diameter × 300mm long) acting as an anti-coincidence guard counter. Brief details are given of the construction and commissioning of the system, including counter assembly, shield design, electronics, data capture, data analysis, and chemical processing and filling procedures. The performance of the system and an overall view of the fields of application for which the counters have important applications are discussed.

Alignment of milliarcsecond with arcsecond scale structure in core-dominated radio sources

1986 ◽  
Vol 64 (4) ◽  
pp. 440-444 ◽  
Author(s):  
Raymond Rusk ◽  
Ann C.M. Rusk
Keyword(s):  
Scale Structure ◽  
Small Samples ◽  
Radio Sources ◽  
Angle Distribution ◽  
Long Baseline ◽  
Relativistic Beaming ◽  
Beam Parameters ◽  
Highly Correlated ◽  
Bend Angles ◽  
Larger Sample

Models of compact radio sources as relativistic jets aligned nearly along the line of sight predict large magnifications of intrinsic jet bends due to projection effects. Several authors have examined the distribution of observed bend angles, for small samples of sources, to provide constraints on the relativistic beaming models. In this study, we examine the alignment of Very Long Baseline Interferometry scale structure with arcsecond scale structure for a much larger sample of core-dominated radio sources and compare the distribution of observed misalignment angles with theoretical distributions calculated from models using a range of intrinsic bend angles, ξ, and Lorentz factors, γ. The theoretical distributions produced by simple relativistic beam models are found to be consistent with the data. However, the values of ξ and γ required to fit the data are highly correlated, with equally good fits produced by γ = 5, ξ = 11° and γ = 10, ξ = 5°, for instance. Either ξ or γ must be known independently for an analysis of the misalignment angle distribution to provide a significant constraint on beam parameters.

scholarly journals Implications of measurement error structure on the visualization of multivariate chemical data: hazards and alternatives

2018 ◽  
Vol 96 (7) ◽  
pp. 738-748 ◽  
Author(s):  
Peter D. Wentzell ◽  
Chelsi C. Wicks ◽  
Jez W.B. Braga ◽  
Liz F. Soares ◽  
Tereza C.M. Pastore ◽  
...  
Keyword(s):  
Data Analysis ◽  
Measurement Error ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Measurement Errors ◽  
Alternative Methods ◽  
Chemical Data ◽  
Multidimensional Data ◽  
Chemical Information ◽  
Components Analysis

The analysis of multivariate chemical data is commonplace in fields ranging from metabolomics to forensic classification. Many of these studies rely on exploratory visualization methods that represent the multidimensional data in spaces of lower dimensionality, such as hierarchical cluster analysis (HCA) or principal components analysis (PCA). However, such methods rely on assumptions of independent measurement errors with uniform variance and can fail to reveal important information when these assumptions are violated, as they often are for chemical data. This work demonstrates how two alternative methods, maximum likelihood principal components analysis (MLPCA) and projection pursuit analysis (PPA), can reveal chemical information hidden from more traditional techniques. Experimental data to compare different methods consists of near-infrared (NIR) reflectance spectra from 108 samples of wood that are derived from four different species of Brazilian trees. The measurement error characteristics of the spectra are examined and it is shown that, by incorporating measurement error information into the data analysis (through MLPCA) or using alternative projection criteria (i.e., PPA), samples can be separated by species. These techniques are proposed as powerful tools for multivariate data analysis in chemistry.

Simulated frosting of tropical grasses

1974 ◽  
Vol 25 (1) ◽  
pp. 45 ◽  
Author(s):  
JB Hacker ◽  
BJ Forde ◽  
JM Gow
Keyword(s):  
Vapour Pressure Deficit ◽  
Frost Tolerance ◽  
Leaf Damage ◽  
Soluble Carbohydrates ◽  
Leaf Surfaces ◽  
Ranking Order ◽  
Simulated Field ◽  
Frost Period ◽  
Relationship Of ◽  
Tropical Grass

Ranking order for leaf damage was determined in six varieties of the tropical grass setaria after frosting in a controlled environment and was found to be similar to known field response. A frost temperature of –2.5°C provided good discrimination between populations subjected to three successive frost cycles of 4 hr under programmed conditions which closely simulated field conditions. Further experiments were carried out to investigate: (a) The relative frost tolerance of a range of varieties in the genera Setaria, Digitaria, Paspalum, and Lolium; (b) the effect of vapour pressure deficit (VPD) during frosting and rate of temperature change into the frost period on leaf damage; (c) the effect of temperatures preceding frosting and duration of frost on leaf damage; (d) the relationship of concentration of alcohol-soluble carbohydrates to susceptibility to frost. The most tolerant tropical grass tested was Paspalum dilatatum. Significant variation in frost tolerance in Setaria was related to altitude of origin, whereas in Paspalum plicatulum latitude of origin appeared to be the controlling factor. Frost tolerance was slightly increased by pre-hardening for 3 days or by growing at a lower night temperature. Frosting at a VPD of –3 mb resulted in less damage than frosting at a VPD of zero, when visible frost formed on leaf surfaces. Extending the duration of the frost resulted in an increase in leaf damage. Ranking order for frost tolerance was not attributable to differences in concentration of alcohol soluble carbohydrates and was not affected by environmental conditions either preceding or during the frost period.

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