Implication Of Plant Clonality For Eco-Remediation

Clonal growth may contribute greatly to plants'adaptation to habitat heterogeneity. Clonal plants may be of important resource value in the studies and practices of eco-remediation. In this thesis, the mechanisms of clonal plants'resistance to drought and wind erosion and their implications for eco-remediation of degraded land are investigated using both field and greenhouse experiments. In the experiments, clonality and its related traits, their plasticity in response to water, and resistance/remediation to wind erosion to wind erosion were compared among two rhizomatous grass species, Leymus secalinus and Psammochloa villosa (hereafter, their genus name are used only), in Ordos Plateau, a semiarid area of China.The results show that number of newly produced ramets was significant correlated with initiation of clonal growth and clonal growth rate, suggesting that initiation of clonal growth (ICG) and the clonal growth rate (CGR) are good indicators for clonality, that Leymus had greater clonality than Psammochloa for its early ICG and high CGR and this difference might be modified by water condition, and that clonality was very plastic in response to water conditions and the plasticity was species-depended. Psammochloa could adapt the habitat better than Leymus.Clonal plants can have two types of propagule: one is seedling and the other ramet. Growth traits and clonality traits were compared between Leymus and Psammochloa as well as between seedlings and ramets in an experiment with water supply as treatment. The results show that: water availability enhances growth of Leymus, whatever from ramet or seed as propagule. However, in Psammochloa water availability suppressed ramet growth but promoted seedling growth. Clonality could be well manifested in full water availability. There was no difference in clonality traits between seedlings and ramets in Leymus. In contrast, water availability had no significant effect on ramet growth, but promoted seedling growth in Psammochloa. It suggested that clonality traits of seedlings and ramets may differ in response to water availability. Psammochloa ramets had better adaptation to drought than seedlings.