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Accueil du site → Doctorat → Chine → 2013 → Studies on Morphology and Function of Root of Typical Desert Plant and Its Drought-resistant Physiology Characteristics on Northwest China

Gansu Agricultural University (2013)

Studies on Morphology and Function of Root of Typical Desert Plant and Its Drought-resistant Physiology Characteristics on Northwest China

单立山; Dan Li Shan

Titre : Studies on Morphology and Function of Root of Typical Desert Plant and Its Drought-resistant Physiology Characteristics on Northwest China

Auteur : 单立山; Dan Li Shan

Grade : Doctoral Dissertation 2013

Université : Gansu Agricultural University

Résumé partiel
The root system is the vegetative organ from which the plants absorb water and nutrition ;moreover, it offers the partial material base for photosynthesis. The root system’smorphological characteristics, spatial distribution and architecture show a great difference indifferent habitats conditions. The study of morphology structure, nutrition characteristics andphysiological characteristics against drought of root system in different habitats conditionsplay a significant role in understanding the root morphological structure and functions inresponding mechanism to environmental factors and the strategy of physiological adaptationwithin the different environments.Based on the typical desert plants Reaumuria soongorica and Nitraria tangutorun in aridand semi-arid regions of northwestern China, according to the precipitation gradient, themethod which combined trenching with root-tracking method were used to mine thewhole-plant roots in this research, and its morphological characteristics and architectureparameters were measured, and its root distribution was drew. At the same time, fine rootsunder different habitats were collected and classificated according to the Pregitzer,sclassification method, and then the root analysis software was used to measure themorphology parameters, and the nutrient characteristics(the content of C、N)of the fine rootwas measured. Under different habitats, morphological characteristics and architectureparameters of two desert plants were discussed, and the response mechanism of them toenvironmental variations was revealed, fine root architecture and morphology and functionalcharacteristics were also clarified. Combined with the water gradient experiment of artificialcontrol conditions, the morphology and function of R. soongorica root were compared underdifferent soil moisture conditions. We further prove the response strategy of the morphologycharacteristics and functions of R. soongorica root to soil moisture variations.1. The taproot growth of the two types of desert plants was restrained with the decrease inprecipitation and increase in drought stress. However, there were some discrepancies amongdifferent species, among which the taproot growth of R.soongorica is evidently restrained.These two types of desert plants can adapt the environmental stress through the morphologicalchange in arid and semi-arid regions in Northwest, China. These two types of desert plants inloess hilly and gully region can adapt the environmental stress through the increase of lateralbranches, the increase of the number of lateral branches and the total root length. Nevertheless, these two types of desert plants in sandy area of Hexi Corridor can adapt the bioticenvironment mainly through prolong the average connecting length which demonstrate theobvious morphological plasticity of the two types of desert plants.2. The root topological indices of the two desert plants were small, and the root branchingpatterns were herringbone-like. The roots of the two desert plants had obvious fractalcharacteristics, with the fractal dimension of R.soongorica and N.tangutorum being (1.18±0.04) and (1.3±0.06), respectively. The root fractal dimension and fractal abundance weresignificantly positively correlated with the root average link length. The root average linklengths of the two plants were long,which enlarged the plants’ effective nutrition space,andthus, made the plants adapt to the dry and infertile soil environment.

Mots clés : Topological indices; Fractal dimension; Specific root length (SRL); Specific root surface area (SRA); C/N ratio; Root order; Root activity;

Présentation (CNKI)

Page publiée le 6 septembre 2014, mise à jour le 29 septembre 2017