Ecological adaptation strategies of the clonal plant Phragmites australis at the Dunhuang Yangguan wetland in the arid zone of northwest China

Abstract

The adaptation strategies of plants are the key scientific issues for studying the mechanism of community formation and restoration of wetland vegetation in arid areas. But there are still unclear areas in the research on the adaptability of Phragmites australis. We studied the differences in physiological, morphological and behavior adaptation of clonal plant P. australis in high, medium and low coverage areas and their driving forces in Inland river wetland of Dunhuang Yangguan, China. The results showed that: 1) Non-structural carbohydrates and starch concentration gradually decreased, while the content of soluble sugar concentration gradually increased during the process from high coverage to low coverage. 2) The stem diameter, node number, and tiller number showed the obvious downward trends, while rhizome internode length, spacer length and branch angle showed the obvious upward trends. 3) From the high coverage area to the low coverage area, the spatial distribution pattern changed from mainly clustered distribution to random distribution, and the clustering intensity significantly decreased (p < 0.05). 4) Driving force research showed that soil water content was significantly positively correlated with starch concentration, stem diameter, node number, tiller number, and aggregation intensity (p < 0.05), and soil water content was negatively correlated with spacer length and branch angle (p < 0.05), but soil salt content was the opposite of soil water content. The physiological, morphological, and behavioral adaptation indicators of P. australis have all changed under different gradients, and more attention should be paid to artificially strengthening water management.