Effect of Flooding Depth on Growth, Biomass, Photosynthesis, and Chlorophyll Fluorescence of Typha domingensis

We examined the growth, biomass, photosynthesis, and chlorophyll fluorescence of Typha domingensis (southern cattail) in response to a six-week period of three flooding depths: 40, 91, and 137 cm above the soil surface and a subsequent four-week period of recovery at a 40-cm flooding depth. The 91- and 137-cm flooding significantly decreased the following: number of new shoots, number of live leaves, leaf, belowground and total biomass, and belowground biomass/leaf ratio. Plants flooded to a 91- or 137-cm depth had significantly lower chlorophyll concentration, photosynthesis, and fluorescence (Fv/Fm) as well as higher dark respiration and light compensation points than those exposed to the 40-cm flooding. Following the recovery period, most adverse impacts caused by the 91-cm flooding depth were reversed in terms of biomass, photosynthesis, and chlorophyll fluorescence, while the effect of the 137-cm flooding stresses exhibited by T. domingensis were not reversed. Flooding to a 137-cm depth is detrimental to T. domingensis and needs to be avoided. Our results indicate that depth-duration thresholds for management of T. domingensis dominated marshes are necessary to minimize deepwater impacts to vegetation communities.