@Article{phyton.2008.77.297,
AUTHOR = {Castellanos-Pérez E, AG de  Soyza, GB  Donart},
TITLE = {Photosynthesis and water use efficiency of the association between <i>Larrea tridentata</i> (DC) Cov. and <i>Muhlenbergia porteri</i> Scribn},
JOURNAL = {Phyton-International Journal of Experimental Botany},
VOLUME = {77},
YEAR = {2008},
NUMBER = {all},
PAGES = {297--320},
URL = {http://www.techscience.com/phyton/v77nall/36910},
ISSN = {1851-5657},
ABSTRACT = {The study was conducted in the Chihuahuan Desert Rangeland Research Center, 32 km north of Las Cruces, NM, USA. Physiological responses of the shrub <i>Larrea tridentata </i>(DC) Cov. and the perennial grass <i>Muhlenbergia porteri</i> Scribn were determined from the summer 1997 to the winter 1998-99 when they grew together. In the summer 1997, <i>Larrea tridentata</i> competed for water with <i>M. porteri</i>, as shrubs growing alone showed higher integrated photosynthesis than shrubs in competition with <i>M. porteri</i> following a heavy rainfall event. <i>Larrea tridentata</i> had lower water use efficiency (WUE) than <i>M. porteri</i> plants. In the summer 1998, <i>M. porteri</i> had greater pre-dawn xylem water potentials (ψ<sub>L</sub>) than <i>L. tridentata</i> when soil water potentials were above -3 MPa. <i>Larrea tridentata</i> showed a higher photosynthetic activity when <i>M. porteri</i> was defoliated than when it remained undefoliated. <i>Muhlenbergia porteri</i> presented a higher WUE. While green in the fall, plants of <i>M. porteri</i> had higher ψ<sub>L</sub> and WUE than those of <i>L. tridentata.</i> Net assimilation was similar between shrub and grass plants. Both species responded to soil moisture availability in this season. <i>Muhlenbergia porteri</i> had higher net assimilation when growing alone than when growing under creosotebush. In the winter season, and while being small, creosotebush had higher photosynthetic activity when growing alone than when growing with <i>M. porteri</i> (p<0.005). Small and large plants of <i>L. tridentata</i> growing alone showed higher photosynthetic activity than <i>L. tridentata</i> growing with <i>M. porteri</i> (p<0.01). In the spring, <i>M. porteri</i> and <i>L. tridentata</i> had the same net assimilation. At this time, however, water loss was lower in <i>M. porteri</i> than in <i>L. tridentata.</i> When soil water potential decreased below -7 MPa, <i>L. tridentata</i> still showed net assimilation.},
DOI = {10.32604/phyton.2008.77.297}
}