Plasticity in bud demography of a rhizomatous clonal plant Leymus chinensis L. in response to soil water status

We surveyed the bud demography of Leymus chinensis L. plants along a soil-moisture gradient that was caused by a flood in 1998 on the Song-nen Plain in northeastern China. The number of vegetative buds per ramet was influenced by soil water content, with regression curves being quadratic and the opening of the parabola pointing downward. in addition, the optimum regression models for the numbers of rhizomatous buds and tiller buds relative to soil water resulted in a quadratic parabola and exponential curve, respectively. Vegetative buds flourished between August and October, with plants producing more of those buds on flooded plots than on control sites. The number of rhizomatous buds per ramet was much higher than for tiller buds throughout most of the growing season, and production of the former was more apt to be affected by soil water status. This observed superiority of rhizomatous bud production was thought to be a consequence of the whole-plant adjustment that was stimulated by an abnormally high moisture content. it could also be interpreted as a strategy for escape from disadvantageous overly wet conditions. Moreover, the position-based preference for bud emergence along the ramets could be an underlying mechanism for selective ramet placement.