Full TGIF Record # 98741
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Web URL(s):http://www.wsweedscience.org//wp-content/uploads/proceedings-archive/2004.pdf#page=45
    Last checked: 12/10/2013
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Publication Type:
Content Type:Abstract or Summary only
Author(s):Wang, Ke; Murray, Leigh W.; Schroeder, Jill; Thomas, Stephen H.
Author Affiliation:Wang: Colorado State University, Fort Collins, Colorado; Murray, Schroeder, and Thomas: New Mexico State University, Las Cruces, New Mexico
Title:Techniques of topological anaylsis for examining purple and yellow nutsedge root architecture
Section:Basic science
Other records with the "Basic science" Section
Meeting Info.:Colorado Springs, Colorado: March 9-11, 2004
Source:Proceedings of the Western Society of Weed Science. Vol. 57, 2004, p. 43-44.
# of Pages:2
Publishing Information:Newark, CA: Western Society of Weed Science
Keywords:TIC Keywords: Nematoda; Roots; Cyperus rotundus; Cyperus esculentus; Root length; Parasites; Root systems
Abstract/Contents:"Root-knot nematodes are important plant parasites that attack nearly all crop and weed species. Much work has been done to examine root-knot nematode effect on plant above- and below-ground biomass. In order to have a better understanding of the interaction between southern root-knot nematode and nutsedge species, a non-destructive mini-rhizotron experiment was conducted to compare the geometric and topological properties of roots for the purple nutsedge and yellow nutsedge in the presence or absence of root-knot nematode. The objective of this poster is to discuss how to apply the concept of topological trees to compare root architecture, which can be described in terms of two extreme cases (herringbone and binary structures) and their intermediates. Data extracted from rhizotron root images include the topological parameters, magnitude (n), altitude (a), and total exterior pathlength (pe), and geometric measures of link counts and lengths, and root depth. We found Generalized Linear Models with Gamma distributions suitable for non-normally distributed length variables. Topological parameters and count variables were analyzed using Generalized Linear Models with Poisson distributions. Usual Analysis of Variance was used for root depth since this data was Normally distributed and hence satisfied the assumptions of Linear Models. We also used a simple linear regression model to obtain the topological index, which is the slope of regressing either log(pe) or log(a) on log(n) (denoted as pe-slope or a-slope respectively). The theoretical maximum value of a-slope is one for a perfect herringbone structure and the theoretical minimum value of pe-slope approaches one for a complete dichotomous structure. The results of our study showed presence of root-knot nematode had some effect on nutsedge root architecture. The presence of root-knot nematode reduced both link length and link numbers, especially in yellow nutsedge root systems. High values of topological indices indicated that both purple and yellow nutsedge favored a more herringbone-like root system, which implied that nutsedge root systems are adapted to poor soil environments where resources are scarce and patchy. We also discovered a potential problem with the regression analysis to obtain topological indices. Without forcing the intercept to be zero, we found that the fitted a-slope can be greater than the theoretical maximum of one with a negative intercept or can be less than one but with a positive intercept which is biologically impossible."
Note:"This article appears as abstract only."
ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Wang, K., L. W. Murray, J. Schroeder, and S. H. Thomas. 2004. Techniques of topological anaylsis for examining purple and yellow nutsedge root architecture. Proc. West. Soc. Weed Sci. 57:p. 43-44.
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    Last checked: 12/10/2013
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    Notes: Item is within a single large file
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MSU catalog number: SB 610 .W43 v.49
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