关键词: 土壤水, 降水, 氘同位素, 西鄂尔多斯荒漠

Abstract: The development of phenotype is restricted by the geometry of plant vascular network. In different environments, plant vascular network makes the structural and functional tradeoff between efficiency and safety, develops different network characters, and thus, induces the plastic responses of phenotype. Despite the importance of vascular network structural acclimation in modifying plant phenotype, this topic has largely been neglected. In this paper, an environmental gradient of three soil textures (sandy soil, clay soil, and 1∶1 sandy soil and clay soil) was installed to study the effects of soil texture on the geometry of root and stem xylem vessels of cotton (Gossypium herbaceum L.) plants as well as the relationships among soil texture, xylem vessel size, and biomass allocation. The results showed that long-term exposure to the soil texture gradient led to a significant change in the vessel traits. The comparison of the plants in the three treatments indicated that the structural differences of the vessels could significantly affect (or wererelated to) the root, shoot, and whole plant hydraulic conductance, end-wall resistance, leaf area, and plant height. These results demonstrated that an increased soil particle size tended to result in a safer hydraulic system rather than a more efficient hydraulic system (safety and efficiency tradeoff).

Key words: precipitation, West Ordos Desert., deuterium isotope, soil water