Báo cáo khoa học: A new data processing system for root growth and ramification analysis: description of methods

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Báo cáo khoa học: "A new data processing system for root growth and ramification analysis: description of methods"A new data processing system for root growth and ramifi-cation analysis: description of methods Colin-Belgrand H. Joannes 2 4 L. Pages 3 DreyerM. E.1 Laboratoire des Sols ef de la Nutrition des Arbres Forestiers,2 Station de Biom6trie, and3 Laboratoire de Bioclimatologie et d’Ecophysiologie Forestiere, INRA, Centre de RecherchesForestieres, BP 35, 54280 Seichamps, and4 Station dAgronomie, INRA, Centre dAvignon, Domaine-de-Saint-Paul, 84000 Montfavet, France acquisition; 2) data storage andIntroduction data growth parameter computation; and 3) the integration of the computed parametersDirect observation of root growth in woody into a developmental model (Pages andseedlings is possible using a ’minirhizo- Aries, 1988). The technical prerequisitestron’. Root growth in this device occurs of this processing system are describedalmost exclusively at the interface be- below.tween the substrate and the lower, trans-parent, rhizotron wall. This method pro-vides a better picture of root morphologyand development, but reduces a three- Data acquisition systemdimensional root system to a plane. Rootgrowth is generally observed every 2ndday; newly formed roots are traced on a Basic principles for analyzing structuraltransparent polyethylene sheet with a dif- features of root pictures are the following:ferent color ink for each date. 1) a root is defined as a linear, un- branched structure formed through the Previous studies of root system charac- activity of a single apical meristem; 2) suc-teristics required time consuming manual cessive root orders are defined accordingprocessing. To overcome this major limita- developmental terminology (Rose,tion, we have recently developed a semi- to a 1983): the taproot originating from theautomated data acquisition system al- hypocotyl is the 1 st order root and bearslowing a quantitative analysis of root 2nd order roots and so on; 3) roots arearchitecture (Belgrand et al., 1987). This treated as sets of elementary straight seg-new data processing system consists of 3 ments, each being the increment in rootsuccessive stages: 1) semi-automatedlength between 2 successive observa- hierarchy. Coordinates and ’structural’tions; 4) each root segment is defined information stored in the data storage are the Cartesian coordinates of someby structure.characteristic points (e.g., terminal points Hardware needed for this processing is(initial and final) and branching points any IBM PC compatible computer equip-where the laterals of the order n +1 ped with a color video screen (EGA orappear); in fact, branching points are also VGA norm) and a graphics tablet. Soft-the initial points of lateral root segments. ware is written in TURBOPASCAL (ver- sion 4.0). Fig. 1 shows a simplified root systemwith 7 segments belonging to 5 different Digitizing begins at the root origin on theroots, a taproot and 4 laterals. Root seg- hypocotyl (the oldest observation). Thement records are completed with auto- observer provides some information aboutmatically computed information about the the experiment, the dates and associatedsegment position in the br ...