土壤水分对入侵植物节节麦表型可塑性和化感作用的影响

采用盆栽试验方法，研究土壤含水量在75%～80%（CK）、55%～60%（MD）和45%～50%（SD）土壤田间持水量条件下对入侵植物节节麦植株表型可塑性及化感作用的影响，探讨节节麦对土壤水分变化的响应机理，为其入侵机制研究提供理论依据。结果表明：节节麦植株总生物量随土壤含水量的降低呈下降变化，至SD时，较CK减少21.19 %。此外，叶生物量比、平均叶面积、相对生长速率及净同化效率均随土壤含水量的降低而减小，而根、穗生物量比、根冠比及水分利用效率则呈逐渐增大变化。化感效应指数显示，随土壤含水量的降低，节节麦不同部位水浸提液的化感作用整体呈先升后降的变化。研究表明，节节麦通过生物量分配模式及对化感物质投入的改变对土壤水分变化有一定的适应能力。

Effects of Soil-water Conditions on Morphological Plasticity and Allelopathic Potential of Invasive Plant Aegilops tauschii Coss.

Studying the responses of plant morphology and biomass allocation under different soil water conditions could help to reveal the mechanism of exotic plant invasion. Pot experiment was conducted to study the morphological plasticity and synthetical allelopathic effect of the invasive alien plant Aegilops tauschii in three different soil water contents which corresponded to relative soil water content 75%~80% (CK), 55%~60% (MD) and 45%~50% (SD). The results showed that the total biomass of A. tauschii decreased with the decrease of soil water content. In addition, as soil water content decreased, growth rate, net assimilation rate, leaf area ratio, leaf mass ratio, stem mass ration and root cap ratio were reduced in varying degrees, while root mass ration, ear mass ratio and water use efficiency showed a gradually increasing trend. According to the inhibition synthesis effect, the allelopathic potential of aqueous leachates of different parts of A. tauschii were increased first and decreased afterwards with the decreased of soil water. These results indicated that A. tauschii have certain adaptability to soil moisture changes by biomass allocation patterns and allelochemicals inputed.