Water absorption by mucilaginous achenes of Artemisia monosperma: Floatingand germination as affected by salt concentrations

Artemisia monosperma is a dominant perennial desert shrub occurring in acti ve sand dunes and stabilized sand fields. A cyanobacterial crust develops o n stabilized sand and, as a result, runoff water may occur after rains. The mucilaginous achenes may float on the runoff water and disperse into depre ssions or cracks. In these experiments, almost half of the achenes remained afloat on distill ed water for 3 days and on different concentrations of salt solutions, more achenes remained afloat for longer. High concentrations of salt inhibit ge rmination. NO, may influence achene germination on cyanobacterial sand crus t. Mucilaginous achenes absorb water within about 60 min, and after 120 min reach their water capacity. The achenes from which the mucilage has been r emoved can float for a longer period and germinate earlier than intact ones . Seedlings that developed from achenes with mucilage had greater Vigor tha n those without. The ecological significances of mucilaginous achenes is discussed.