Water relations of Chusquea ramosissima and Merostachys claussenii in Iguazu National Park, Argentina

Bamboos are prominent components of many tropical ecosystems, yet little is known about the physiological mechanisms utilized by these gigantic forest grasses. Here, we present data on the water transport properties of Chusquea ramosissima and Merostachys claussenii, monocarpic bamboo grasses native to the subtropical Atlantic forests of Argentina. C. ramosissima and M. claussenii differed in their growth form and exhibited contrasting strategies of water transport. Maximum xylem hydraulic conductivity of C. ramosissima culms was 2-fold higher than that of M. claussenii. C. ramosissima cavitated at relatively high water potentials (50% loss of conductivity at >or=1 MPa), whereas M. claussenii was more drought tolerant (50% loss at <or=3 mpa).="" both="" species="" exhibited="" significant="" loss="" of="" hydraulic="" conductivity="" during="" the="" day,="" which="" was="" reversed="" overnight="" due="" to="" generation="" root="" pressure.="" photosynthetic="" capacities="" bamboo="" species,="" estimated="" based="" on="" electron="" transport="" rates,="" were="" moderate,="" reflecting="" large="" amount="" leaf="" area="" supported="" by="" culms="" and="" diurnal="" cavitation.="" conductance="" also="" relatively="" low="" for="" congruent="" with="" their="" modest="" capacities.="" within="" its="" native="" range,="" c.="" ramosissima="" is="" highly="" invasive="" ability="" colonize="" persist="" in="" forest="" gaps="" land="" cleared="" agriculture.="" we="" propose="" that="" a="" vulnerable="" vasculature,="" coupled="" pressure="" an="" allometry="" allows="" substantial="" be="" slender="" culms,="" are="" key="" traits="" contributing="" ecological="" success="" ramosissima.<="" div="">