Clonal water integration characteristics and ecological significance of Populus euphratica Oliv. in hyper-arid habitats

Clonal integration is one of the most important strategies of clonal plants to effectively use heterogeneous resources and adapt to adverse habitats for colonization and survival.Using Populus euphratica Oliv.from the lower reaches of Tarim River as research material,we studied its clonal water integration and ecological significance based on multiple field investigation methods,stable isotopic tracing,and ecophysiology monitoring experiments.Results showed obvious water integration between adult mother P.euphratica and young daughter ramets,which was characterized by acropetal water transport.Water integration was influenced by the physiological rhythm of the mother trees and spacer length connecting the adult and young daughter trees.Compared with P.euphratica seedlings,the young ramets could take more water from deep soil layers,like its adult mother tree,due to clonal integration.This,in turn,contributed to better water acquisition capability,better hydraulic conductivity performance,higher leaf water content,and higher leaf water potential of young ramets than that of seedlings.This water acquisition strategy in hyper-arid habitats allows young ramets to maintain higher photochemical efficiency and photosynthetic activity than that of seedlings,and consequently contributes to higher survival advantages for young ramets than for seedlings.