Biology Reference
In-Depth Information
Chapter 6
MOLECULAR BIOLOGY OF THE
NICOTIANA
FLORAL NECTARY
ROBERT W. THORNBURG
Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames,
Iowa 50011, USA
1
INTRODUCTION
The secretion of floral nectar in most angiosperms is under very specific de-
velopmental control. Secretion begins when the flowers open and continues
while the flowers remain receptive to pollination. Nectar flow is often in-
creased by pollinator visitation. However, after pollination, nectar secretion
ceases and the remaining nectar may be reabsorbed (Búrquez & Corbet, 1991;
Nepi et al., 1996b, 2001; Stpiczyńska, 2003).
To take advantage of the very powerful recombinant DNA methodology
that is available to today's molecular biologists, it is almost imperative that
one focuses attention on a single species, or even a single plant line that be-
comes the model plant for any given trait.
Arabidopsis thaliana
has served as
an excellent model plant for many traits and physiological measurements.
The genetic, biochemical, and molecular biological resources available for
Arabidopsis
researchers far surpass those available for any other species.
Unfortunately, while
Arabidopsis
is excellent for many traits, it is not a good
model for nectar and nectary analysis, because the nectaries are small and
inconspicuous and are lost when the flower falls. Therefore, to evaluate the
biochemistry and molecular biology of the floral nectary, we have investi-
gated many species of plants and have focused on a diploid ornamental
tobacco line. As a genetic tool, tobacco is not as desirable as
Arabidopsis
.
Still, several advantages of ornamental tobacco have led us to choose this
line as our model organism.
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