Environmental Engineering Reference
In-Depth Information
Current regulations restricting field releases of all transgenes in time and space need to be
replaced with regulations that recognize different levels of risk (as determined by the origin of the
transgene, its impact on reproductive fitness, and nontarget impacts) and assign a commensurate level
of confinement. The next step in determining the acceptability of transgene technology for forest tree
improvement is the unconfined release of constructs that pose little risk in terms of gene escape and
nontarget impacts (e.g., lignin-altered poplar or pine) to permit evaluation of ecological risks and
environmental or agronomic benefits at relevant scales (van Frankenhuyzen and Beardmore 2004).
2 7. 7 s u m m a r y
It is clear from the literature that
Paulownia
species have been used as a multipurpose tree in many
countries in the east. There has been a growing interest in Paulownia in the western world since the
1970s. Countries that lack large forested areas and must therefore import timber can use Paulownia
to help establish a local supply program around it (El-Showk and El-Showk 2003). It is a highly
sought after companion tree in many agroforestry models in China. Further, it is well known for
its fast growth and high biomass accumulation. Because of this property, it will it very well in the
present scene of lignocellulosic feedstock production.
Genetic modifications by plant transformation allow for stable alterations in biochemical
processes that direct traits such as increased yield, disease and pest resistance, increased vegetative
biomass, herbicide tolerance, nutritional quality, drought and stress tolerance, and genes to improve
the production of ethanol from lignocellulosic biomass. In these methods, foreign constructs are
introduced into the plant cell, followed by isolation of cells containing the foreign DNA integrated
into the cell's DNA, to produce stably transformed plant cells. To date Paulownia has been selected
primarily to enhance its growth rate and wood quality value. Thus, it has been managed primarily as
a forest crop for which these traits are important. These targets are quite different from the criteria
for biofuel crops for which high biomass yield, high cellulose, and traits involved with bioprocessing
to ethanol are essential. Paulownia provides a great opportunity to develop transgenic Paulownia
trees with desirable characteristics including higher cellulose and lower lignin content, disease
resistance, and tolerance to a wide variety of biotic and abiotic stress conditions. Multipurpose
attributes of the Paulownia tree justify thorough research for the deeper understanding of the plant
biology related to medicinal properties, biomass production, and positive environmental and eco-
nomic impact. In addition to this, a resource that has not been tapped to its full potential is marginal
farmland, specifically its use for growing tree crops. More than 30 million acres of woodland and
idle pasture and cropland exist in the Southeast, and much of this land could be producing valuable
tree crops (Clatterbuck and Hodges 2004), with Paulownia being one of them.
acknoWledGments
Paulownia research at Fort Valley State University (FVSU) is being carried out through an Evans
Allen grant (GEOX 5213) funded to the author. Author expresses gratitude to Dr. K. C. Das at
the Bioengineering Department (University of Georgia, Athens) for analyzing Paulownia wood,
Vicki Owen for maintaining “Paulownia Demonstration Plot” at FVSU and Scot Corbett (World
Paulownia Institute, Lenox, GA) for sharing information and pictures, and assisting in setting up
“Paulownia Demonstration Plot” Paulownia demonstration farm at FVSU.
REFERENCES
Ates S, Ni Y, Akgul M, Tozluoglu A (2008) Characterization and evaluation of
Paulownia elongata
as a raw
material for paper production.
Afr J Biotechnol
7:4153-4158
Bergmann BA (1998) Propagation method influences first year field survival and growth of Paulownia.
New
Forests
16(3):251-264
Bergmann BA, Moon H-K (1997) Adventitious shoot production in
Paulownia
.
Plant Cell Rep
16:315-319
