Ecophysiological Responses of C3 Forbs and C4 Grasses to Drought and Rain on a Tallgrass Prairie in Northeastern Kansas

Abstract

Ecophysiological responses to drought and a 3-cm rain were measured in seven C3 forb and five C4 grass species on a tallgrass prairie in northeastern Kansas. In general, midday leaf water potentials and conductances increased after rain to a greater extent in the C3 forbs, although exceptions occurred. In particular, the deeply rooted Silphium laciniatum showed little or no change in water potential and three of the five grass species exhibited no change in conductance. Although the above differences in species and life-form responses were noted, few of the species exhibited signs of severe stress at the height of the drought, emphasizing the degree to which both C3 forbs and C4 grasses are adapted to occasional severe droughts in the prairies of North America.