PS 86-124 - Growth and ecophysiological characteristics of an exotic woody invasive plant

Friday, August 12, 2011
Exhibit Hall 3, Austin Convention Center
Tosin A. Sekoni1, Thomas W. Boutton2, Cristine L. Morgan3, Georgianne W. Moore2 and Robert Knight1, (1)Ecosystem Science and Management, Texas A&M University, College station, TX, (2)Ecosystem Science and Management, Texas A&M University, College Station, TX, (3)Department of Soil and Crop Science, Texas A&M University, College station, TX

Chinese tallow tree (Triadica sebifera) is invading the coastal prairies of the Gulf of Mexico, altering the structure and function of these endangered ecosystems.  The purpose of this study was to examine the response of this exotic invasive tree to different levels of water stress, and to determine the stress threshold that may inhibit tallow’s growth and establishment.  In addition, we sought to determine if tallow’s water-use efficiency (WUE) would change in response to water stress.  The study was conducted in a semi-green house at the University of Houston Coastal Center, (La Marque, Texas).  Tallow seeds were planted in 3.8-L pots containing local soil.  Plants were then grown under three water stress levels (high, intermediate, and low, n = 25 plants/treatment).  After six months, we recorded shoot height, shoot diameter, and leaf count.  Leaf tissues were analyzed for δ13C by isotope ratio mass spectrometry to assess WUE. 


Shoot height, shoot diameter and leaf count all decreased significantly under high water stress (p<0.0001).  Foliar δ13C values increased significantly with increasing water stress (p<0.05), suggesting greater WUE under water limited conditions.  Results indicate that, while this invasive tree’s growth is significantly reduced under intense drought conditions, its ability to tolerate and survive drought may be enhanced by increased WUE, suggesting one mechanism by which this woody invader may be able to tolerate soil water limitations in subtropical coastal prairies. 

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