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Accueil du site → Doctorat → Chine → 2014 → Studies of the Effects of Accumulated CaCO_3in Soil on the Phenotypic Plasticity of Artemisia Ordosica in Arid and Semi-arid Areas and Their Mechanisms

Université de Nankai (2014)

Studies of the Effects of Accumulated CaCO_3in Soil on the Phenotypic Plasticity of Artemisia Ordosica in Arid and Semi-arid Areas and Their Mechanisms

薛苹苹;

Titre : Studies of the Effects of Accumulated CaCO_3in Soil on the Phenotypic Plasticity of Artemisia Ordosica in Arid and Semi-arid Areas and Their Mechanisms

Auteur : 薛苹苹;

Grade : Doctoral Dissertation 2014

Université : Université de Nankai

Résumé
Artemisia ordosica Krasch. is an important constructive species on sandy land in the northwest of China, which is widely distributed in the Kubuqi desert, Mu Us Sandy land, Tengger Desert, Ulan Buh Desert, and Hexi Corridor sandy land in Gansu Province. A. ordosica plays an important role in desert and sandy land revegetation. Therefore, the stability of A. ordosica community is not only a significant practical problem, but also an important scientific issue. Preliminary study from the laboratory of Ecology of Nankai University showed that, A. ordosica community would be replaced by Ceratoides arborescens or Artemisia. frigida community, and the accmumulaton of calcium carbonate could affect the density of A. ordosica community. Theoretical analysis showed that, if the accumulation of calcium carbonate can affect the density of A. ordosica community, it can also affect its size and biomass. In other words, calcium carbonate would affect the phenotypic plasticity of A. ordosica plants, which needs to be confirmed by experiments.In this study, the inhibitive effects of accumulated calcium carbonate on A. ordosica seedlings were investigated by performing potting experiments, the effects of N/P ratios on the raletive growth rates of seedlings were also examined ; the effects of accumulated calcium carbonate on the RNA contents in A. ordosica were investigated by field sampling analysis. To comprehensively analyze the inhibitive effects of accumulated calcium carbonate on the phenotypic plasticity of A ordosica and their possible mechanisms, the calcium carbonate contents in arid and semi-arid areas and the features of calcium components in A. ordosica from different geographical regions, as well as the calcium component contents in A. ordosica plants from arid and semi-arid areas, were studied. The four main results of this research were summarized as follows:1. To examine the response of A. ordosica seedlings to different concentrations of soil calcium carbonate, potting experiments were performed in Greenhouse. The results showed that, with the soil calcium carbonate concentrations increased, the root length, and the increment of plant height and root reduced, and the growth of the roots were restrained. The results of determination of N and P contents in seedlings showed that, the contents of N and P of the seedlings without calcium carbonate addition were significantly higher than those with calcium carbonate addition. The N contents decreased with the calcium carbonate contents increased. The P contents exhibited the same trends as that of N contents. The regression analysis showed that, the root relative growth rates showed significant logarithmic negative correlation with the N/P ratios, while showed logarithmic positive correlation with P contents of the seedlings. This result indicated that, accumulated calcium carbonate in the soil affected the phenotypic plasticity to A. ordosica seedlings, and the N/P ratios of A. ordosica seedlings were the direct cause.2. Representative A. ordosica communities were selected from natural habitats, and the plant and soil samplings were colleted, which were analyzed in the laboratory. The soil calcium carbonate contents and RNA contents in the A. ordosica leaves were determined. The results showed that, the soil calcium carbonate contents increased as the sandy land was fixed. However, RNA contents in the leaves showed the opposite trend. The regression analysis showed the same results. This result confirmed the results of the potting experiments as mentioned above. P availability in soil is affected by the increase of calcium carbonate, which can also affect the RNA content in plants

Mots clés : Artemisa ordosica Krasch; phenotypic plasticity; soil calcium carbonate; RNA; calcium component in plant;

Présentation (CNKI)

Page publiée le 26 septembre 2017